A flow direction level resilience evaluation method and system for highland wide area single channel

Abstract

The application relates to the fields of traffic engineering and intelligent traffic technology, and discloses a flow direction level resilience evaluation method and system for a plateau wide-area single-channel. The method comprises the following steps: obtaining target plateau area evaluation data and identifying the traffic demand range of a single-channel traffic structure; directionally dividing the traffic demand according to the traffic demand range to form a flow direction unit; extracting basic operation parameters in the flow direction unit to form traffic operation state parameters of each flow direction unit; monitoring the traffic operation state parameters of each flow direction unit to obtain time sequence operation data of each flow direction unit in a full disturbance cycle; obtaining a response feature set and a performance index of each flow direction unit according to the time sequence operation data; and weighting and fusing the performance index to obtain a flow direction level resilience evaluation value and a resilience level division. The application finely depicts the sensitivity difference of different direction traffic flows to disturbance under the constraint condition of a plateau wide-area single-channel, and provides a basis for traffic organization optimization and emergency support.

Description

Technical Field

[0001] This invention relates to the fields of traffic engineering and intelligent transportation technology, specifically to a flow-oriented resilience assessment method and system for wide-area single-channel traffic in plateau regions. Background Technology

[0002] With the continuous development of regional transportation networks, the transportation system in plateau regions plays a vital role in regional connectivity, resource transportation, and emergency response. Constrained by topography, climate, and ecological environment, the road network structure in plateau regions generally exhibits a limited number of routes and a scarcity of alternative paths. Some road sections bear a highly concentrated traffic function in the region, and disruptions such as road closures, traffic control, or severe weather can easily trigger large-scale traffic disruptions, seriously affecting regional traffic safety and efficiency.

[0003] To enhance the ability of transportation systems to cope with disturbance events, various methods for assessing the resilience of transportation systems have been proposed in the existing technology. These methods typically analyze the performance changes of transportation systems under disturbance conditions from the perspectives of traffic operation efficiency, network connectivity, or system reliability. However, existing resilience assessment methods mostly use the segment level or road network level as the assessment object, focusing on changes in the overall performance of the transportation system, and are difficult to reflect the differentiated operational characteristics exhibited by different traffic flows in a single-lane traffic structure.

[0004] In high-altitude, wide-area single-channel traffic scenarios, different traffic flows exhibit significant differences in their dependence on the single channel. Furthermore, the impact range, intensity, and recovery process of disturbance events vary across these flows. Using only segment-level or network-level resilience assessments can easily obscure the vulnerability characteristics of key flows and make it difficult to promptly identify sensitive flows that have a decisive impact on regional traffic operations. This limits the practical application value of the assessment results in traffic organization optimization and emergency management.

[0005] In addition, some existing technologies focus on the instantaneous operating status or a single performance index after a disturbance occurs when conducting resilience assessments. They lack a systematic characterization of the response characteristics of the traffic system throughout the entire process before, during, and after a disturbance, resulting in the need to further improve the completeness and accuracy of the assessment results.

[0006] Therefore, there is an urgent need for a method that is suitable for high-altitude, wide-area, single-channel traffic scenarios and can comprehensively assess the resilience, adaptability, and recovery capabilities of traffic systems under disturbance conditions from the perspective of flow direction, so as to achieve a refined characterization and effective identification of the resilience of traffic systems. Summary of the Invention

[0007] To address the shortcomings of existing traffic resilience assessment methods, which are mostly based on road segment or road network levels and are difficult to adapt to the characteristics of wide-area single-channel traffic structures in plateau regions, and also difficult to characterize the differences in operation of different traffic flows under disturbance conditions, this invention proposes a flow-oriented resilience assessment method and system for wide-area single-channel traffic in plateau regions. By comprehensively assessing the resistance, adaptability, and recovery capacity of the traffic system under disturbance conditions from the perspective of traffic flow, this invention achieves a refined characterization of the traffic system's resilience and provides support for traffic operation management and emergency response.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0009] This invention provides a method for assessing the flow-oriented toughness of a wide-area single channel in high-altitude regions, comprising the following steps: S1. Obtain the data to be evaluated for the target plateau area, establish a road network topology model based on the data to be evaluated, and identify single-channel or quasi-single-channel traffic structures from the road network topology model, as well as the traffic demand range of the single-channel or quasi-single-channel traffic structures. The data to be evaluated includes road network structure data, traffic operation data, and environmental constraint data. S2, based on the scope of traffic demand, the relationship between traffic origin and destination, the direction of road traffic and the main traffic routes, the traffic demand is directionally divided to form several flow units; S3, extract the basic operating parameters from the flow direction unit, calculate the flow direction characteristic parameters, and form the traffic operation status parameters of each flow direction unit; S4 monitors the traffic operation status parameters of each flow unit to obtain the time-series operation data of each flow unit during the entire disturbance cycle; S5, construct the flow direction operation performance function of each flow direction unit based on the time-series operation data, and form the corresponding flow direction operation performance curve. Based on the flow direction operation performance curve, obtain the response feature set of each flow direction unit. S6. Based on the response feature set and flow feature parameters of each flow unit, calculate the anti-interference index, adaptability index and resilience index of each flow unit. S7, the disturbance rejection index, adaptability index and resilience index of each flow unit are weighted and fused to obtain the flow-level toughness evaluation value of the flow unit, and the toughness level is classified according to the flow-level toughness evaluation value of the flow unit.

[0010] Furthermore, single-lane or quasi-single-lane traffic structures are identified from the road network topology model, specifically including: The effective number of target channels, the number of alternative paths, the comprehensive impedance of alternative paths, and the total available capacity of alternative channels are extracted from the road network topology model to obtain initial channel data; based on the initial channel data and preset conditions, single-channel or quasi-single-channel traffic structures are identified. The preset conditions include preset conditions for single-lane traffic structure identification and preset conditions for quasi-single-lane traffic structure identification. Preset conditions for single-lane traffic structure identification include: The number of valid channels does not exceed the preset number, and the number of alternative paths is lower than the preset threshold; or, The total available capacity of alternative channels is lower than the preset capacity threshold; The preset conditions for identifying quasi-single-lane traffic structures include: Alternative routes exist, but the overall impedance of these alternative routes exceeds a preset impedance threshold, and the total available capacity of the alternative routes is insufficient to support a preset proportion of traffic demand.

[0011] Furthermore, step S2 specifically includes: Within the range of traffic demand, a preliminary classification is performed based on the traffic origin-destination relationship and the direction of road traffic to obtain preliminary classification results; Based on the preliminary classification results, traffic demand in the same direction is further subdivided according to the main travel routes, resulting in a detailed classification result. Traffic demands with the same or similar directions of travel and with the same or similar main travel routes are grouped into the same flow direction unit.

[0012] Furthermore, step S3 specifically includes: Set the time window length; Within each time window, basic operating parameters are statistically analyzed for each flow unit. These basic operating parameters include flow rate, speed, travel time, and congestion status. The congestion status is determined based on the rate of speed decrease, the rate of travel time extension, or a service level threshold. Calculate the flow direction characteristic parameters for each flow direction unit, including flow direction channel dependence, detour accessibility, and alternative channel availability.

[0013] Furthermore, step S4 specifically includes: Construct a main channel disturbance scenario for a single-channel or quasi-single-channel transportation structure in the plateau region; Traffic operation parameters of each flow unit are monitored in three stages: before the disturbance occurs, during the disturbance duration, and during the recovery period. This yields time-series operation data for each flow unit throughout the entire disturbance cycle. The stage before the disturbance occurs is used to obtain stable operation status, the stage during the disturbance duration is used to reflect the degradation process after the channel is disturbed, and the recovery period is used to reflect the recovery process after the disturbance is resolved.

[0014] Furthermore, step S5 specifically includes: After standardizing the traffic operation status parameters of each flow direction unit, a weighted sum is calculated to construct the flow direction operation performance function, which is used to calculate the flow direction operation performance value of each flow direction unit at a certain moment. Connect the flow direction performance values ​​of the same flow direction unit in chronological order before the disturbance occurs, during the disturbance duration, and during the recovery period to form the flow direction performance curve of that flow direction unit.

[0015] Furthermore, the immunity index of each flow element is used to characterize the first... The performance retention capability of each flow unit during the main channel disturbance process is calculated using the following formula:

[0016] in, For the interference immunity index of each flow element, The baseline performance value before the disturbance occurred. This represents the lowest performance value during the disturbance process.

[0017] Furthermore, the adaptability index is used to characterize the first... The ability of a flow unit to maintain traffic connection by relying on detour routes and alternative routes under the condition that the main channel is disturbed is calculated by the following formula:

[0018] in, As an adaptive indicator, For flow-direction channel dependence, For detour accessibility, To replace channel availability, , and Let be the weighting coefficient, and satisfy... .

[0019] Furthermore, the restorative index is used to characterize the first... The performance recovery capability of each flow element after disturbance removal is calculated using the following formula:

[0020] in, The performance value at the end of the recovery phase. The time corresponding to the lowest performance value, To restore the completion time.

[0021] Secondly, this invention proposes a flow-oriented resilience assessment system for a wide-area single channel in plateau regions, including a data acquisition module and a data processing module. The data acquisition module is used to acquire the data to be evaluated in the target plateau area, including road network structure data, traffic operation data, and environmental constraint data. The data processing module is used to obtain the flow-direction level toughness assessment value of the flow-direction unit and classify the toughness level by using the flow-direction level toughness assessment method for a wide-area single channel in plateau as described above.

[0022] Compared with existing technologies, the beneficial effects of this invention are as follows: Addressing the limitations of existing technologies in adapting to the characteristics of wide-area single-channel traffic structures in plateau regions and in characterizing the differences in traffic flow operation under disturbance conditions from a flow direction perspective, this invention provides a flow direction-level resilience assessment method for wide-area single-channel traffic systems in plateau regions. This method enables a refined assessment of the traffic system's resistance to disturbance, adaptability, and recovery capabilities under disturbance conditions, and identifies low-resilience or critically sensitive flow directions. It is used to quantitatively assess the operational stability and recovery capabilities of different traffic flow directions under disturbance conditions in complex environments of plateau regions, providing a basis for traffic operation management and emergency response. Attached Figure Description

[0023] Figure 1 This is a flow-oriented toughness assessment method for a wide-area single channel in plateau regions, as described in Example 1. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0025] To address the shortcomings of existing traffic resilience assessment methods, which often focus on road segments or road networks and are ill-suited to the characteristics of wide-area single-channel traffic structures in plateau regions, and fail to characterize the differences in traffic flow under disturbance conditions, this invention provides a flow-oriented resilience assessment method for wide-area single-channel traffic in plateau regions. This method addresses road traffic scenarios in plateau regions characterized by a limited number of channels, scarce alternative routes, significant detour resistance, and limited traffic capacity. First, it constructs a road network topology model of the target area and identifies single-channel or quasi-single-channel traffic structures within the area that serve as the primary traffic links, taking into account the terrain, meteorological, and traffic capacity conditions of the plateau region. Based on this, it determines the range of traffic demand affected by the target channel according to traffic origin-destination needs and main travel routes. This traffic demand is further divided into several flow-oriented units with the same or similar travel directions and main route characteristics, which serve as the basic objects for subsequent resilience assessment.

[0026] After forming flow direction units, this invention further extracts traffic operation status parameters for each flow direction unit at a preset time scale. These parameters include, on the one hand, basic operation parameters such as flow rate, speed, travel time, and congestion status, reflecting the actual operation status of each flow direction unit at each moment; on the other hand, they include flow direction characteristic parameters such as flow direction channel dependence, detour accessibility, and alternative channel availability, reflecting the dependence of different flow direction units on target channels, detour conditions after the main channel is disrupted, and the carrying capacity of alternative channels. Thus, a joint characterization of the differences in traffic demand operation and structure in different directions can be achieved.

[0027] Furthermore, this invention constructs a main channel disturbance scenario for plateau single-channel or quasi-single-channel traffic structures. This disturbance scenario simulates the process of traffic interruption, reduced capacity, or increased impedance of the target channel under the influence of road closures, traffic accidents, traffic control, road construction, severe weather conditions, or geological disasters. For this disturbance scenario, the traffic operation status parameters of each flow unit are continuously monitored before the disturbance occurs, during the disturbance duration, and during the recovery period, obtaining time-series operation data for each flow unit throughout the entire disturbance process.

[0028] Based on the aforementioned time-series operational data, this invention constructs a flow direction operational performance function for each flow direction unit and generates a corresponding flow direction operational performance curve. The flow direction operational performance curve characterizes the entire process of each flow direction unit transitioning from a stable state to a degraded state and gradually recovering under the influence of main channel disturbance. Furthermore, based on the descent-recovery process of the flow direction operational performance curve, response features such as disturbance trigger time, minimum performance point, degradation duration, performance loss area, recovery completion time, and recovery rate are extracted, thereby achieving a dynamic characterization of the disturbance response process of different flow direction units.

[0029] After obtaining the above response characteristics, this invention quantifies the resilience of each flow direction unit from three dimensions: immunity, adaptability, and resilience. Immunity characterizes the flow direction unit's ability to maintain performance during main channel disturbances; adaptability characterizes the flow direction unit's ability to maintain traffic connections using detour paths and alternative routes under main channel disturbance conditions; and resilience characterizes the flow direction unit's ability to recover performance after the disturbance is resolved. Finally, the above three types of indicators are standardized and weighted to obtain the flow direction-level resilience assessment value for each flow direction unit. Based on the assessment value, resilience levels are classified to identify low-resilience flow directions or critically sensitive flow directions.

[0030] Unlike existing resilience assessment methods that focus on road segments or road networks, this invention uses flow direction units affected by the target corridor as the basic assessment granularity. This allows for the revelation of differences in degradation depth, substitution capacity, and recovery speed of traffic demand in different directions under the same main corridor disturbance conditions, thereby achieving a refined assessment of the resilience of a plateau wide-area single-channel transportation system.

[0031] The identification of single-lane or quasi-single-lane traffic structures is based on the number of effective lanes, the number of alternative routes, the comprehensive impedance of alternative routes, and the total available capacity of alternative lanes. When the number of effective lanes carrying the main traffic connection function does not exceed a preset number, and the number of alternative routes is lower than a preset threshold, or the total available capacity of alternative lanes is lower than a preset capacity threshold, it can be identified as a single-lane traffic structure. When alternative routes exist, but the comprehensive impedance of the alternative routes is higher than a preset impedance threshold, and the total available capacity of alternative lanes is insufficient to support a preset proportion of traffic demand, it can be identified as a quasi-single-lane traffic structure.

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0033] Example 1 A flow-oriented resilience assessment method for wide-area single-channel applications in plateau regions, flowchart as follows: Figure 1 As shown, it includes the following steps: S1. Obtain road network structure data, traffic operation data, and environmental constraint data for the target plateau region, and construct a road network topology model. Combining the terrain, weather, and traffic guarantee conditions of the plateau region, based on the number of effective channels, the number of alternative routes, the impedance of alternative routes, and the availability of alternative channels, assess the availability and substitutability of channels that undertake the main traffic connection functions in the region, identify single-channel or quasi-single-channel traffic structures, and determine the scope of traffic demand affected by the single-channel or quasi-single-channel traffic structures based on traffic origin and destination demands and main traffic routes.

[0034] S2. Within the scope of traffic demand affected by the single-channel or quasi-single-channel traffic structure, traffic demand is directionally divided based on traffic origin-destination relationships, road traffic directions, and main traffic routes, forming several flow units with the same or similar traffic directions and main traffic route characteristics.

[0035] S3. Under a preset time scale, extract basic operating parameters for each flow unit and calculate flow characteristic parameters to form traffic operation status parameters for each flow unit; wherein, the basic operating parameters include one or more of flow rate, speed, travel time and congestion status, and the flow characteristic parameters include one or more of flow channel dependence, detour accessibility and alternative channel availability.

[0036] S4. Construct a main channel disturbance scenario for a single-channel or quasi-single-channel traffic structure in the plateau region. The disturbance scenario includes event scenarios that cause the target channel to be interrupted, its capacity to decrease, or its impedance to increase. Continuously monitor the traffic operation status parameters of each flow unit before the disturbance occurs, during the disturbance duration, and during the recovery period to obtain the time-series operation data of each flow unit during the disturbance process.

[0037] S5. Construct the flow direction operation performance function of each flow direction unit based on the traffic operation state parameters, obtain the flow direction operation performance value of each flow direction unit during the disturbance process, and form a flow direction operation performance curve characterizing the process before disturbance, degradation and recovery; extract the response features of each flow direction unit based on the descent-recovery process of the flow direction operation performance curve, the response features include one or more of the following: disturbance trigger time, minimum performance point, degradation duration, performance loss area, recovery completion time and recovery rate.

[0038] S6. Based on the response characteristics and combined with the flow characteristic parameters of each flow unit, calculate the disturbance immunity index, adaptability index, and recoverability index of each flow unit; wherein, the disturbance immunity index is used to characterize the performance maintenance capability of the flow unit during the disturbance of the main channel, the adaptability index is used to characterize the ability of the flow unit to maintain traffic connection by relying on detour paths and alternative channels under the condition of disturbance of the main channel, and the recoverability index is used to characterize the performance recovery capability of the flow unit after the disturbance is removed.

[0039] S7. The disturbance rejection index, adaptability index and resilience index of each flow unit are standardized and fused according to preset weights to obtain the flow-level toughness assessment value corresponding to each flow unit; the toughness level is divided according to the flow-level toughness assessment value using the preset threshold method or quantile method, and the flow-level toughness assessment value below the preset threshold is identified as a low toughness flow or a critical sensitive flow.

[0040] As a specific embodiment, the plateau region is a region with an average altitude higher than a preset threshold; the single-channel or quasi-single-channel traffic structure refers to a road traffic structure in which the number of effective channels undertaking the main traffic connection function in a given area does not exceed a preset number, and the number of alternative paths, overall impedance, or available traffic capacity are limited.

[0041] Furthermore, the identification of single-lane or quasi-single-lane traffic structures includes: extracting the number of effective channels, the number of alternative paths, the comprehensive impedance of alternative paths, and the total available capacity of alternative channels for the target channel; when the number of effective channels carrying the main traffic connection function does not exceed a preset number, and the number of alternative paths is lower than a preset threshold, or the total available capacity of alternative channels is lower than a preset capacity threshold, it is identified as a single-lane traffic structure; when alternative paths exist, but the comprehensive impedance of the alternative paths is higher than a preset impedance threshold, and the total available capacity of alternative channels is insufficient to support a preset proportion of traffic demand, it is identified as a quasi-single-lane traffic structure.

[0042] The overall impedance of alternative routes refers to the comprehensive quantitative value of the travel cost of all alternative routes from the starting point to the end point of the target corridor. It is not merely a matter of route length, but a broad cost that integrates multiple dimensions such as travel time, turning complexity, road grade, toll conditions, and the number of traffic lights. Its core function is to reflect the efficiency and convenience of alternative routes. A lower overall impedance indicates that the alternative route is closer to the traffic quality of the main corridor and has a stronger diversion capacity; conversely, a higher impedance means that the alternative route is a longer detour, takes longer, or has poorer road conditions.

[0043] Typical approaches to calculating the combined impedance of alternative paths include: Simple form: the average or minimum impedance of each alternative path.

[0044] More comprehensive form: Total impedance = ∑(path length × w 1 + free flow time × w 2 + number of turns × w 3+…).

[0045] Commonly used alternative indicators: travel time, generalized cost (time + fuel consumption + toll), detour factor, etc.

[0046] The total available capacity of alternative routes primarily refers to the maximum additional traffic flow diverted from the target route that all alternative routes can handle per unit of time (e.g., per hour). Its core function is to measure the upper limit of the diversion capacity of the alternative route network. The higher this value, the stronger the system's ability to absorb traffic and the better its resilience when the main route experiences disturbances. It is typically the remaining capacity, i.e., the difference between the current occupied traffic and the designed capacity of the alternative routes themselves. ; in, It is the total available capacity. Let be the throughput of the q-th alternative path. For current traffic, if an alternative path is saturated ( ≥ Its available capabilities are 0.

[0047] By combining the two indicators of alternative path integrated impedance and alternative channel total availability, it is possible to quantitatively determine whether the target channel is in a "unique or nearly unique" critical position in the network.

[0048] Furthermore, the flow direction unit is a set of traffic flows that have the same or similar traffic origin and destination directions, main travel paths, and traffic demand characteristics within the traffic demand range affected by single-channel or quasi-single-channel traffic structures.

[0049] Furthermore, the flow-direction channel dependence is used to characterize the first... The degree of dependence of each flow unit on the target channel is calculated using the following formula:

[0050] in, For the first The flow channel dependency of each flow unit For the first Traffic demand for each flow unit via the target channel For the first Total traffic demand for each flow unit.

[0051] Furthermore, the detour reachability is used to characterize the first The reachability of a flow unit to maintain passage via alternative paths under conditions where the target channel is disrupted is calculated using the following formula:

[0052] in, For the first Accessibility of each flow unit via bypass, For the first The number of alternative paths corresponding to each flow unit For the first The reachability identifier of the alternative path, when the first A value of 1 is assigned if an alternative path is feasible, otherwise a value of 0 is assigned. The target channel corresponds to the main path impedance. For the first Alternative path impedance.

[0053] Furthermore, the availability of the alternative channel is used to characterize the effectiveness of the alternative channel for the first... The carrying capacity of traffic demand in each flow unit is calculated using the following formula:

[0054] in, For the first Availability of alternative channels for each flow unit For the first Available capacity of alternative routes or alternative passages. For the first Total traffic demand for each flow unit.

[0055] Furthermore, the main channel disturbance scenario includes event scenarios that cause the target channel to be interrupted, its capacity to decrease, or its impedance to increase. The event scenarios include one or more of the following: road closure, traffic accident, traffic control, road occupation due to construction, severe weather conditions, or geological disaster.

[0056] Furthermore, the flow direction operation performance function is obtained by weighting the traffic operation state parameters of each flow direction unit after standardization, and its calculation formula is as follows:

[0057] in, For the first Each flow unit at time The flow direction performance value, For the first The first flow unit Standardized indicators at time The value of , For the first The weights of the indicators, and satisfying: .

[0058] Furthermore, the response features are extracted based on the decline-recovery process of the flow direction operation performance curve of each flow direction unit; wherein, the disturbance trigger time is the moment when the flow direction operation performance value drops more than a preset threshold relative to the benchmark performance value, the performance minimum point is the minimum value of the flow direction operation performance value during the disturbance process, and the recovery completion time is the moment when the flow direction operation performance value recovers to the benchmark performance value by a preset proportion and continues for a preset duration.

[0059] Furthermore, the disturbance immunity index is used to characterize the first... The performance retention capability of each flow unit during the main channel disturbance process is calculated using the following formula:

[0060] in, For the first The immunity index of each flow unit For the first The baseline performance values ​​of each flow element before the disturbance occurs. This represents the lowest performance value during the disturbance process.

[0061] Furthermore, the adaptability index is used to characterize the first... The ability of a flow unit to maintain traffic connection by relying on detour routes and alternative routes under the condition that the main channel is disturbed is calculated by the following formula:

[0062] in, For the first Adaptability indicators of each flow unit For flow-direction channel dependence, For detour accessibility, To replace channel availability, , and Let be the weighting coefficients, and satisfy:

[0063] Furthermore, the restorative index is used to characterize the first... The performance recovery capability of each flow element after disturbance removal is calculated using the following formula:

[0064] in, For the first The recovery index of each flow unit, The performance value at the end of the recovery phase. This represents the lowest performance value during the disturbance process. The time corresponding to the lowest performance value, To restore the completion time, This represents the baseline performance value before the disturbance occurred.

[0065] Furthermore, the flow-level resilience assessment value is obtained by weighted fusion of immunity index, adaptability index, and resilience index, and its calculation formula is as follows:

[0066] in, For the first The flow-level toughness assessment value of each flow element. , and Let be the weighting coefficients, and satisfy: .

[0067] Example 2 This embodiment provides a flow-level resilience assessment method for a wide-area single-channel road network in a plateau region. Taking a wide-area trunk corridor in a plateau mountainous area as an example, this region is constrained by high altitude, complex terrain, severe weather, and traffic guarantee conditions. The road network contains target corridors that undertake major inter-regional traffic connections, but the number of alternative routes is limited, the detour distance is long, and the alternative capacity is insufficient, exhibiting typical single-channel or quasi-single-channel traffic structure characteristics. The method process of this invention is described below.

[0068] Step (1) Road network topology modeling, single-channel identification and traffic demand range determination In this embodiment, road network structure data, traffic operation data, and environmental constraint data for the target plateau region are first acquired. The road network structure data includes road segments, nodes, road connectivity, corridor composition, and alternative route information; the traffic operation data includes flow rate, speed, travel time, congestion status, and traffic origin-destination demand; and the environmental constraint data includes altitude, slope, meteorological conditions, geological disaster impacts, and traffic guarantee capabilities.

[0069] A road network topology model is constructed based on the road network structure data. ,in, Represents a set of nodes. This represents the set of connecting edges. Each connecting edge is assigned attributes such as travel capacity, free-flow time, actual travel time, and path impedance to form a basic network that can be used for path search and channel identification.

[0070] After the road network topology model is constructed, the availability and substitutability of candidate channels that undertake the main traffic connection functions in the region are analyzed. Specifically, the number of effective channels corresponding to the candidate channels is first counted; then, under the conditions of target channel failure, capacity reduction, or impedance increase, an alternative path set is extracted based on the path search method to obtain the number of alternative paths, and the comprehensive impedance of each alternative path and the total available capacity of the alternative channels are further calculated.

[0071] The comprehensive impedance of the alternative route can be calculated based on the length of the alternative route, travel time, road grade, and traffic conditions; the total available capacity of the alternative route can be obtained by summing up the available capacity of all feasible alternative routes.

[0072] Furthermore, the number of effective channels, the number of alternative routes, the overall impedance of alternative routes, and the total available capacity of alternative channels are compared with preset thresholds. When the number of effective channels carrying the main traffic connection function does not exceed the preset number, and the number of alternative routes is lower than the preset threshold, or the total available capacity of alternative channels is lower than the preset capacity threshold, the candidate channel is identified as a single-channel traffic structure. When alternative routes exist, but the overall impedance of the alternative routes is higher than the preset impedance threshold, and the total available capacity of alternative channels is insufficient to support a preset proportion of traffic demand, the candidate channel is identified as a quasi-single-channel traffic structure.

[0073] After identifying single-lane or quasi-single-lane traffic structures, the scope of traffic demand affected by the structure is further determined based on traffic origin-destination demand and main travel routes. Specifically, the main travel routes corresponding to each traffic origin-destination demand within the area are searched. When the main travel route of a certain traffic origin-destination demand passes through the target lane, or when the proportion of the traffic origin-destination demand passing through the target lane to its total demand exceeds a preset threshold, that traffic origin-destination demand is included in the scope of affected traffic demand.

[0074] After the above processing, the road network topology model of the target area, the identified single-channel or quasi-single-channel traffic structure, and the range of traffic demand affected by the channel structure are obtained, which serve as the basis for subsequent flow direction unit division.

[0075] Step (2) Flow direction unit division Within the aforementioned affected traffic demand range, traffic demand is directionally divided based on traffic origin-destination relationships, road traffic directions, and main traffic routes, forming several flow direction units.

[0076] Specifically, traffic origin and destination demands are first initially classified according to the direction of travel, and then traffic demands within the same direction are further subdivided according to the main travel routes; traffic demands with the same or similar directions of travel and the same or similar main travel routes are grouped into the same flow unit.

[0077] In this embodiment, the flow direction unit is not a simple set of road segments, nor is it a unified evaluation object for the entire road network. Instead, it is a set of directional traffic demands influenced by the target corridor. Through this division, traffic demands in different directions that were originally mixed in the same road network can be decomposed into multiple analysis objects with independent traffic characteristics and substitution characteristics, thereby providing a foundation for subsequent flow direction-level resilience assessment.

[0078] After the above processing, the flow direction unit set is obtained. Each flow unit corresponds to a type of traffic flow with the same or similar travel direction and main travel path characteristics.

[0079] Step (3) Extraction of traffic operation status parameters Under a preset time scale, basic operating parameters are extracted for each flow direction unit, and flow direction characteristic parameters are calculated to form traffic operation status parameters for each flow direction unit.

[0080] First, set the time window length. Within each time window, basic operating parameters, including flow rate, are statistically analyzed for each flow unit. ,speed Travel time and congestion status Congestion can be determined based on the magnitude of speed reduction, the extent of travel time extension, or a service level threshold.

[0081] Next, the flow direction characteristic parameters of each flow direction unit are calculated.

[0082] No. Flow channel dependence of each flow unit The formula used to characterize the dependence of the flow unit on the target channel is as follows: ; in, For the first Traffic demand for each flow unit via the target channel For the first Total traffic demand for each flow unit. The larger the value of , the higher the dependence of the flow unit on the target channel.

[0083] No. Accessibility of each flow unit via bypass The formula used to characterize the accessibility of a flow unit to maintain passage via alternative paths under conditions where the target channel is disrupted is as follows: ; in, For the first The number of alternative paths corresponding to each flow unit For the first The reachability identifier of the alternative path, when the first A value of 1 is assigned if an alternative path is feasible, otherwise a value of 0 is assigned. The target channel corresponds to the main path impedance. For the first Alternative path impedance. The larger the value of , the stronger the ability of the flow unit to maintain contact through alternative paths after the main channel is disturbed.

[0084] No. Availability of alternative channels for each flow unit The formula used to characterize the capacity of alternative corridors to carry traffic demand in this flow direction unit is as follows: ; in, For the first Available capacity of alternative routes or alternative passages. The larger the value of , the stronger the capacity of the alternative channel to meet the traffic demand of the flow unit.

[0085] After completing the above calculations, the basic operating parameters and flow direction characteristic parameters are summarized to form a set of traffic operation status parameters for each flow direction unit under each time window. Unlike assessments based solely on road segment operating status, this embodiment further characterizes the differentiated sensitivity characteristics of different flow direction units under main channel disturbance conditions through flow direction channel dependence, detour accessibility, and alternative channel availability.

[0086] Step (4) Construction of main channel disturbance scenario and process monitoring In this embodiment, a main channel disturbance scenario is constructed for a single-channel or quasi-single-channel traffic structure in plateau areas. The disturbance scenario includes event scenarios that lead to traffic interruption, reduced traffic capacity, or increased traffic impedance of the target channel.

[0087] Specifically, the disturbance scenarios may include one or more of the following: road closures, traffic accidents, traffic control, road construction, severe weather conditions, or geological disasters. For example, scenarios such as reduced traffic capacity of the target passage due to snowfall and icing, temporary interruption of the target passage due to landslides and rockfalls, and increased traffic resistance of the target passage due to temporary traffic control may be set up.

[0088] After the disturbance scenario is set up, the traffic operation status parameters of each flow unit are continuously monitored in three stages: before the disturbance occurs, the duration of the disturbance, and the recovery period. The stage before the disturbance occurs is used to obtain the stable operation status, the duration of the disturbance is used to reflect the degradation process after the channel is disturbed, and the recovery period is used to reflect the recovery process after the disturbance is removed.

[0089] After the above monitoring, the time-series operational data of each flow unit over the entire disturbance period were obtained. This time-series operational data serves as the direct input for constructing flow performance curves and extracting response features.

[0090] Step (5) Construction of flow direction performance function and extraction of response features Based on the time-series operational parameters of each flow unit's disturbance process extracted in step (3) and continuously monitored in step (4), this step selects the basic operational parameters used to characterize operational performance and constructs the flow operational performance function. Since the basic operational parameters such as flow rate, speed, travel time, and congestion status differ in dimensions, magnitude, and quality, they cannot be directly weighted and fused. Therefore, it is necessary to first process the basic operational parameters within each time window to be homogenized and dimensionless. For benefit-type indicators such as flow rate and speed, the larger the standardized value, the better the operational status. For cost-type indicators such as travel time and congestion status, a reverse conversion is performed first, followed by standardization, so that all standardized indicators meet the evaluation direction of "the larger the value, the better the operational performance".

[0091] Standardization mainly refers to the dimensionless and homogenization transformation of basic operating parameters to ensure consistency in dimensions, magnitude, and evaluation direction, which facilitates subsequent weighted fusion to construct the operating performance function.

[0092] Specifically, it includes two steps: Homogenization Conversion: Convert all indicators to a benefit-oriented direction where "the larger the value, the better the performance." For indicators such as flow rate and speed, which are inherently benefit-oriented, maintain the original values ​​or directly standardize them. For cost-oriented indicators such as travel time and congestion status, first perform a reverse conversion (e.g., take the reciprocal or use the difference between the maximum values).

[0093] Dimensionless standardization: This method maps homogenized data to a uniform scale (such as the [0,1] interval or a standard normal distribution with a mean of 0 and a standard deviation of 1), eliminating differences in dimensions and magnitudes. Common methods include min-max normalization or Z-score standardization.

[0094] After standardization, the standardized indicators are weighted and summed according to preset weights to obtain the first standardization index. Each flow unit at time Flow direction operation performance value The calculation formula is as follows: ; in, For the first The first flow unit Standardized operational indicators at any time The value of , The corresponding indicator weights, and satisfying .

[0095] After obtaining the flow direction performance values ​​at each moment, the same flow direction unit is compared with the values ​​before the disturbance occurs, during the disturbance duration, and during the recovery period. Connecting them in chronological order forms the flow direction performance curve of the flow direction unit. This flow direction performance curve characterizes the entire process of the flow direction unit transitioning from a stable state to a degraded state and then gradually recovering from the degraded state under the influence of main channel disturbances. By constructing the flow direction performance curves for each flow direction unit separately, the differentiated degradation and recovery processes of different flow direction units under the same disturbance can be depicted.

[0096] Furthermore, to extract response features, a baseline performance value is first determined based on the flow direction performance value within a preset time window before the disturbance occurs. In this embodiment, the average value of the flow to the operating performance value within a consecutive time window before the disturbance occurs can be used as the benchmark performance value.

[0097] Subsequently, when the decrease in the flow performance value relative to the baseline performance value exceeds a preset threshold, the corresponding moment is determined as the disturbance trigger moment. From the moment the disturbance is triggered, the minimum value of the flow direction performance curve is searched during the duration of the disturbance, and this minimum value is determined as the lowest performance value. And its corresponding time is determined as the time corresponding to the lowest performance. .

[0098] After determining the minimum performance value, the area between the baseline performance value and the actual flow direction performance curve between the disturbance trigger time and the recovery completion time is calculated to obtain the performance loss area. Specifically, this can be calculated using a discrete accumulation method, and its expression is as follows: ; in, For the first The performance loss area of ​​each flow unit This represents the length of the time window.

[0099] Furthermore, the flow direction performance curve during the recovery phase is analyzed. When the flow direction performance value recovers to a preset percentage of the baseline performance value and remains so for a preset duration, the corresponding moment is determined as the recovery completion moment. Subsequently, the recovery rate is calculated based on the performance recovery magnitude and recovery duration between the time corresponding to the lowest performance value and the time of recovery completion.

[0100] After the above processing, the first result can be obtained. The response feature set of each flow unit includes at least the disturbance trigger time, minimum performance value, degradation duration, performance loss area, recovery completion time, and recovery rate. This response feature set serves as the basic input for subsequent calculations of immunity and recovery metrics.

[0101] Step (6) Calculation of three types of resilience indicators In this embodiment, based on the response characteristics obtained in step (5) and combined with the flow direction characteristic parameters obtained in step (3), the anti-interference index, adaptability index and recovery index of each flow direction unit are calculated.

[0102] Among them, the anti-interference index Used to characterize the The performance retention capability of each flow unit during the main channel disturbance process is calculated using the following formula: ; in, The baseline performance value before the disturbance occurred. This represents the lowest performance value during the disturbance process. After calculation, The larger the value, the higher the performance level of the flow element under disturbance, and the stronger its immunity to disturbance.

[0103] Adaptability Indicators Used to characterize the The ability of a flow unit to maintain traffic connection by relying on detour routes and alternative routes under the condition that the main channel is disturbed is calculated by the following formula: ; in, For flow-direction channel dependence, For detour accessibility, To replace channel availability, , and Let be the weighting coefficient, and satisfy... After calculation, The larger the value, the stronger the alternative passage capability and traffic connection capability of the flow unit when the main passage is disturbed.

[0104] Restorative indicators Used to characterize the The performance recovery capability of each flow element after disturbance removal is calculated using the following formula: ; in, The performance value at the end of the recovery phase. The time corresponding to the lowest performance value, To restore the completion time. After calculation, The larger the value, the faster the flow unit recovers and the higher the degree of recovery.

[0105] After the above processing, the disturbance resistance index, adaptability index, and resilience index of each flow direction unit are obtained. This yields three types of resilience components corresponding to each flow direction unit, rather than a unified evaluation result for a specific road segment or the entire road network.

[0106] Step (7) Calculation of flow - level resilience evaluation value and identification of sensitive flows In this embodiment, the resistance index, adaptability index, and recovery index of each flow unit are pre - processed to eliminate the differences in dimension and value scale.

[0107] Subsequently, the three types of indexes are weighted and fused according to the preset weights to obtain the flow - level resilience evaluation value of the th flow unit , and its calculation formula is: ; where , and are weight coefficients, and satisfy .

[0108] In this embodiment, after obtaining the flow - level resilience evaluation values of all flow units, the flow - level resilience evaluation values of each flow unit are denoted as R, and the R values of all flow units are sorted from low to high. This embodiment uses the quantile method to divide the flow - level resilience levels.

[0109] Specifically, calculate the 10th percentile P10, 25th percentile P25, median P50, and 75th percentile P75 of the flow - level resilience evaluation values of all flow units respectively. When R ≤ P10, the corresponding flow unit is determined as an extremely low - resilience flow and is identified as a key sensitive flow; when P10 < R ≤ P25, the corresponding flow unit is determined as a relatively low - resilience flow and is identified as a low - resilience flow; when P25 < R ≤ P50, the corresponding flow unit is determined as a medium - resilience flow; when P50 < R ≤ P75, the corresponding flow unit is determined as a relatively high - resilience flow; when R > P75, the corresponding flow unit is determined as a high - resilience flow.

[0110] The reason for using the quantile method to set the resilience level threshold in this embodiment is that the core purpose of flow - level resilience evaluation is not only to judge whether a certain flow reaches a fixed numerical standard, but to identify the traffic flows that are relatively more sensitive, have weaker substitution ability, or poorer recovery ability within the same plateau wide - area single - channel traffic system. The quantile threshold can adaptively determine the level boundary according to the distribution characteristics of the actual evaluation samples, avoiding the distortion of the identification results caused by differences in regional traffic conditions, disturbance intensity, or sample size for a fixed threshold.

[0111] Thus, this embodiment can identify relatively low - resilience flows and key sensitive flows under different application scenarios, providing a basis for traffic organization optimization, emergency support plan formulation, and priority resource allocation. [[ID=***]]

[0112] Further explanation In some implementations, the index weights in step (5) Adaptive weights in step (6) , , and the fusion weights in step (7) , , The value can be determined using a pre-set weighting method, entropy weighting method, analytic hierarchy process, or calibration method based on historical disturbance samples.

[0113] In some implementations, the recovery completion time in step (5) can be defined as the time when the flow performance value recovers to 80%, 85%, 90% or other preset ratios of the baseline performance value and continues for several time windows.

[0114] In some implementations, the main channel disturbance scenario in step (4) can be set as a single disturbance event or as multiple consecutive disturbance events, depending on actual needs.

[0115] Example 3 This invention provides a method for assessing the flow-oriented toughness of a wide-area single channel in high-altitude regions, comprising the following steps: S1. Obtain road network structure data, traffic operation data, and environmental constraint data for the target plateau region, and construct a road network topology model. Considering the characteristics of limited number of plateau road network channels, scarcity of alternative routes, and limited traffic guarantee capacity, identify single-channel or quasi-single-channel traffic structures that undertake the main traffic connection functions based on the number of effective channels, the number of alternative routes, the impedance of alternative routes, and the availability of alternative channels, and determine the scope of traffic demand affected by them.

[0116] S2. Within the stated traffic demand range, based on traffic origin-destination relationships, road traffic directions, and main traffic routes, traffic demand is directionally divided to form several flow direction units with the same or similar traffic directions, main traffic routes, and demand characteristics. This division decomposes the traffic demand that might be averaged under the same main corridor disturbance into different flow direction objects, reflecting the differences in the dependence of traffic flows in different directions on the main corridor.

[0117] S3. For each flow direction unit, extract basic operating parameters such as flow rate, speed, travel time, and congestion status, and calculate flow direction characteristic parameters such as flow direction channel dependence, detour accessibility, and alternative channel availability. The basic operating parameters are used to describe the actual operating status of the flow direction unit, while the flow direction characteristic parameters are used to describe its structural vulnerability and alternative maintenance capability after the main channel is disturbed.

[0118] S4. In response to scenarios such as road closures, traffic accidents, road construction, traffic control, severe weather, or geological disasters that cause the main channel to be interrupted, its capacity to decrease, or its impedance to increase, the traffic operation status parameters of each flow unit are continuously monitored before the disturbance occurs, during the disturbance duration, and during the recovery period to obtain time-series operation data for the entire disturbance cycle.

[0119] The full disturbance cycle typically refers to the complete period from the occurrence of a disturbance event (such as a traffic accident, severe weather, or construction) until the traffic system fully recovers to its normal or new stable operating state. This cycle generally includes three key phases: the pre-disturbance stabilization period (normal system operation), the disturbance impact period (system performance degrades and reaches its lowest point), and the recovery period (the system gradually recovers to an acceptable level of stability). By monitoring the time-series operational data throughout this complete cycle, the resilience characteristics of the flow units before and after the disturbance, such as resistance, adaptability, and recovery capabilities, can be comprehensively assessed.

[0120] S5. Based on the time-series operation data, the basic operation parameters are processed to be oriented and dimensionless, a flow direction operation performance function is constructed, a flow direction operation performance curve is formed, and response features such as disturbance trigger time, minimum performance point, degradation duration, performance loss area, recovery completion time and recovery rate are extracted to characterize the performance degradation degree and recovery process of each flow direction unit under the main channel disturbance.

[0121] S6. Based on the response characteristics and flow characteristic parameters of each flow direction unit, calculate the disturbance immunity index, adaptability index, and recovery index respectively. Among them, disturbance immunity characterizes the performance maintenance capability of the flow direction unit when the main channel is disturbed, adaptability characterizes its ability to maintain traffic connection by relying on detour paths and alternative channels, and recovery characterizes the performance recovery capability after the disturbance is removed.

[0122] S7. The anti-interference, adaptability, and resilience indices are standardized and weighted to obtain the flow-level resilience assessment value for each flow unit. Resilience levels are then classified according to threshold, quantile, or historical sample calibration methods to identify low-resilience or critically sensitive flow directions. The "standardization" here is similar to the previous processing of basic operating parameters, but the object changes to three resilience dimensions (interference resistance, adaptability, and resilience). Its core purpose remains the same: to eliminate differences in dimensions, magnitude, and direction, enabling them to be weighted and fused into a comprehensive flow-level resilience value.

[0123] Furthermore, single-lane or quasi-single-lane traffic structures are identified from the road network topology model, specifically including: The effective number of target corridors, the number of alternative paths, the comprehensive impedance of alternative paths, and the total available capacity of alternative corridors are extracted from the road network topology model to obtain initial corridor data. Based on the initial corridor data and preset conditions, single-channel or quasi-single-channel traffic structures are identified. The preset conditions include preset conditions for single-lane traffic structure identification and preset conditions for quasi-single-lane traffic structure identification. Preset conditions for single-lane traffic structure identification include: The number of valid channels does not exceed the preset number, and the number of alternative paths is lower than the preset threshold; or, The total available capacity of alternative channels is lower than the preset capacity threshold; The preset conditions for identifying quasi-single-lane traffic structures include: Alternative routes exist, but the overall impedance of these alternative routes exceeds a preset impedance threshold, and the total available capacity of the alternative routes is insufficient to support a preset proportion of traffic demand.

[0124] Furthermore, step S2 specifically includes: Based on traffic origin and destination demands, a preliminary classification is performed according to the direction of travel, resulting in a preliminary classification. Based on the preliminary classification results, traffic demand in the same direction is further subdivided according to the main travel routes, resulting in a detailed classification result. Traffic demands with the same or similar directions of travel and with the same or similar main travel routes are grouped into the same flow direction unit.

[0125] Furthermore, step S3 specifically includes: Set the time window length; Within each time window, basic operating parameters are statistically analyzed for each flow unit. These basic operating parameters include flow rate, speed, travel time, and congestion status. The congestion status is determined based on the rate of speed decrease, the rate of travel time extension, or a service level threshold. Calculate the flow direction characteristic parameters for each flow direction unit, including flow direction channel dependence, detour accessibility, and alternative channel availability.

[0126] Furthermore, step S5 specifically includes: Construct a main channel disturbance scenario for a single-channel or quasi-single-channel transportation structure in the plateau region; Traffic operation parameters of each flow unit are monitored in three stages: before the disturbance occurs, during the disturbance duration, and during the recovery period. This yields time-series operation data for each flow unit throughout the entire disturbance cycle. The stage before the disturbance occurs is used to obtain stable operation status, the stage during the disturbance duration is used to reflect the degradation process after the channel is disturbed, and the recovery period is used to reflect the recovery process after the disturbance is resolved.

[0127] Furthermore, step S5 specifically includes: The flow operation performance function is constructed by standardizing and weighting the traffic operation status parameters of each flow unit. The flow operation performance function is used to calculate the flow operation performance value of each flow unit at a certain moment. Connect the flow direction performance values ​​of the same flow direction unit in chronological order before the disturbance occurs, during the disturbance duration, and during the recovery period to form the flow direction performance curve of that flow direction unit.

[0128] Furthermore, the immunity index of each flow element is used to characterize the first... The performance retention capability of each flow unit during the main channel disturbance process is calculated using the following formula: ; in, The baseline performance value before the disturbance occurred. This represents the lowest performance value during the disturbance process.

[0129] Furthermore, the adaptability index is used to characterize the first... The ability of a flow unit to maintain traffic connection by relying on detour routes and alternative routes under the condition that the main channel is disturbed is calculated by the following formula: ; in, For flow-direction channel dependence, For detour accessibility, To replace channel availability, , and Let be the weighting coefficient, and satisfy... .

[0130] Furthermore, the restorative index is used to characterize the first... The performance recovery capability of each flow element after disturbance removal is calculated using the following formula: ; in, The performance value at the end of the recovery phase. The time corresponding to the lowest performance value, To restore the completion time.

[0131] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for assessing the flow-oriented toughness of a single channel over a wide area in plateau regions, characterized in that, Includes the following steps: S1. Obtain the data to be evaluated for the target plateau area, establish a road network topology model based on the data to be evaluated, and identify single-channel or quasi-single-channel traffic structures from the road network topology model, as well as the traffic demand range of the single-channel or quasi-single-channel traffic structures. The data to be evaluated includes road network structure data, traffic operation data, and environmental constraint data. S2, based on the scope of traffic demand, the relationship between traffic origin and destination, the direction of road traffic and the main traffic routes, the traffic demand is directionally divided to form several flow units; S3, extract the basic operating parameters from the flow direction unit, calculate the flow direction characteristic parameters, and form the traffic operation status parameters of each flow direction unit; S4 monitors the traffic operation status parameters of each flow unit to obtain the time-series operation data of each flow unit during the entire disturbance cycle; S5, construct the flow direction operation performance function of each flow direction unit based on the time-series operation data, and form the corresponding flow direction operation performance curve. Based on the flow direction operation performance curve, obtain the response feature set of each flow direction unit. S6. Based on the response feature set and flow feature parameters of each flow unit, calculate the anti-interference index, adaptability index and resilience index of each flow unit. S7, the disturbance rejection index, adaptability index and resilience index of each flow unit are weighted and fused to obtain the flow unit's flow-level toughness assessment value, and the toughness level is classified according to the flow unit's flow-level toughness assessment value. The immunity index of each flow element is used to characterize the first... The performance retention capability of each flow unit during the main channel disturbance process is calculated using the following formula: in, For the interference immunity index of each flow element, The baseline performance value before the disturbance occurred. This represents the lowest performance value during the disturbance process; The adaptability index is used to characterize the first... The ability of a flow unit to maintain traffic connection by relying on detour routes and alternative routes under the condition that the main channel is disturbed is calculated by the following formula: in, As an adaptive indicator, For flow-direction channel dependence, For detour accessibility, To replace channel availability, , and Let be the weight coefficient, and satisfy... ; The recovery index is used to characterize the first... The performance recovery capability of each flow element after disturbance removal is calculated using the following formula: in, The performance value at the end of the recovery phase. The time corresponding to the lowest performance value, To restore the completion time.

2. The flow-oriented toughness assessment method for a wide-area single channel in plateau regions as described in claim 1, characterized in that, Identifying single-lane or quasi-single-lane traffic structures from the road network topology model specifically includes: The effective number of target channels, the number of alternative paths, the comprehensive impedance of alternative paths, and the total available capacity of alternative channels are extracted from the road network topology model to obtain initial channel data; single-channel or quasi-single-channel traffic structures are identified based on the initial channel data and preset conditions. The preset conditions include preset conditions for single-lane traffic structure identification and preset conditions for quasi-single-lane traffic structure identification. Preset conditions for single-lane traffic structure identification include: The number of valid channels does not exceed the preset number, and the number of alternative paths is lower than the preset threshold; or, The total available capacity of alternative channels is lower than the preset capacity threshold; The preset conditions for identifying quasi-single-lane traffic structures include: Alternative routes exist, but the overall impedance of these alternative routes exceeds a preset impedance threshold, and the total available capacity of the alternative routes is insufficient to support a preset proportion of traffic demand.

3. The method for assessing the flow-oriented toughness of a wide-area single channel in plateau regions as described in claim 1, characterized in that, Step S2 specifically includes: Within the range of traffic demand, a preliminary classification is performed based on the traffic origin-destination relationship and the direction of road traffic to obtain preliminary classification results; Based on the preliminary classification results, traffic demand in the same direction is further subdivided according to the main travel routes, resulting in a detailed classification result. Traffic demands with the same or similar directions of travel and with the same or similar main travel routes are grouped into the same flow direction unit.

4. The flow-oriented toughness assessment method for a wide-area single channel in plateau regions as described in claim 1, characterized in that, Step S3 specifically includes: Set the time window length; Within each time window, basic operating parameters are statistically analyzed for each flow unit. These basic operating parameters include flow rate, speed, travel time, and congestion status. The congestion status is determined based on the rate of speed decrease, the rate of travel time extension, or a service level threshold. Calculate the flow direction characteristic parameters for each flow direction unit, including flow direction channel dependence, detour accessibility, and alternative channel availability.

5. The method for assessing flow-oriented toughness in a wide-area single channel on plateaus as described in claim 1, characterized in that, Step S4 specifically includes: Construct a main channel disturbance scenario for a single-channel or quasi-single-channel transportation structure in the plateau region; Traffic operation parameters of each flow unit are monitored in three stages: before the disturbance occurs, during the disturbance duration, and during the recovery period. This yields time-series operation data for each flow unit throughout the entire disturbance cycle. The stage before the disturbance occurs is used to obtain stable operation status, the stage during the disturbance duration is used to reflect the degradation process after the channel is disturbed, and the recovery period is used to reflect the recovery process after the disturbance is resolved.

6. The method for assessing flow-oriented toughness in a wide-area single channel on plateaus as described in claim 1, characterized in that, Step S5 specifically includes: After standardizing the traffic operation status parameters of each flow direction unit, a weighted sum is calculated to construct the flow direction operation performance function, which is used to calculate the flow direction operation performance value of each flow direction unit at a certain moment. Connect the flow direction performance values ​​of the same flow direction unit in chronological order before the disturbance occurs, during the disturbance duration, and during the recovery period to form the flow direction performance curve of that flow direction unit.

7. A flow-oriented resilience assessment system for wide-area single-channel applications in high-altitude regions, characterized in that, It includes a data acquisition module and a data processing module; The data acquisition module is used to acquire the data to be evaluated in the target plateau area, including road network structure data, traffic operation data, and environmental constraint data. The data processing module is used to classify the toughness level by obtaining the flow-direction toughness assessment value of the flow-direction unit through the flow-direction toughness assessment method for wide-area single channel in plateau as described in any one of claims 1-6.

Images