A method for evaluating traffic risk of mountainous highway network in multiple scales and dimensions

Abstract

The present application belongs to the technical field of expressway traffic risk assessment, and discloses a method for multi-scale and multi-dimensionally evaluating traffic risk of mountainous expressway network, comprising the following steps: S1. constructing a unified dimension framework for evaluating traffic risk of mountainous expressway network; S2. based on the dimension framework for evaluating traffic risk constructed in step S1, establishing a longitudinal and through risk evaluation scale framework for three spatial scales of structure point, road section and road network; S3. multi-scale risk evaluation coupling; S4. based on the evaluation model of each scale, outputting corresponding traffic risk value and risk level. The method can provide basis for customized management and control strategy of infrastructure, effectively reduce single-point accident risk; can provide basis for optimizing the layout of traffic safety facilities, adjusting law enforcement points, and timely releasing road condition information, and guarantee smooth and orderly traffic flow on road section; can provide basis for road network safety operation management and planning upgrade, and effectively improve the safety and management efficiency of mountainous expressway operation.

Description

Technical Field

[0001] This invention belongs to the field of highway traffic risk assessment technology, specifically involving a method for multi-scale and multi-dimensional assessment of traffic risks in mountainous highway networks. Background Technology

[0002] Due to complex geological conditions and frequent extreme weather, the operation of mountain expressways faces multiple risks, including geological disasters, floods, deterioration of road infrastructure technology, and emergencies, posing a severe challenge to driving safety, smooth traffic flow, road network resilience, and management efficiency.

[0003] To address the shortcomings of existing risk assessments for mountain expressways, which often focus on a single scale and lack systematic analysis, it is necessary to consider the multidimensional causes of traffic risks and establish a systematic traffic risk assessment system that integrates "points, lines, and networks" to meet the practical needs of safe operation management of mountain expressways in Chongqing.

[0004] Patent CN120823728A describes a risk assessment model that selects road alignment, traffic flow, meteorological, and environmental resilience indicators. It constructs a risk assessment model using fuzzy comprehensive evaluation and calculates the traffic safety risk level for each road segment. This addresses, to some extent, the problem of one-sided risk identification caused by single-factor analysis in existing technologies and provides a systematic characterization of complex risk scenarios. However, it only focuses on isolated road segment-level risk assessment and does not consider the transmission effect of risks across different scales, failing to characterize risk chain reactions. Furthermore, the prevention and control strategies lack adaptability to risk characteristics at different scales, leaving room for improvement in overall systemicity and practicality. Patent CN109191828B provides a traffic participant accident risk prediction method based on ensemble learning, enabling automatic identification of high-risk individuals and improving the targeting of traffic safety management. However, it only considers raw traffic violation and accident data, lacking correlation analysis of multi-dimensional factors such as road technical conditions, meteorological conditions, and traffic flow, thus failing to characterize complex risk scenarios and limiting the accuracy and practicality of risk prediction. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method for multi-scale and multi-dimensional assessment of traffic risks in mountainous expressway networks. This invention aims to quantitatively assess traffic risks caused by multiple factors along mountainous expressways, including natural disasters, topography, road infrastructure technical conditions, meteorological conditions, and traffic flow. It achieves a multi-scale assessment of expressway point-line-network traffic risks from a local to a holistic perspective, analyzes high-risk situations, and supports a comprehensive judgment on expressway operational safety.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for assessing traffic risks in mountainous expressway networks at multiple scales and dimensions includes the following steps:

[0008] S1. Construct a unified framework for assessing traffic risks on mountainous expressway networks;

[0009] S2. Based on the risk assessment dimension framework constructed in step S1, a vertically integrated risk assessment dimension framework is established for the three spatial scales of structural points, road segments, and road networks.

[0010] Structural points refer to key locations that are highly susceptible to geological disasters. These are high-risk disaster locations identified through the Ministry of Transport's "Technical Guidelines for Comprehensive Risk Assessment of Highway Disaster-Bearing Bodies in Natural Disasters." Among these, key locations highly susceptible to geological disasters include bridge sections, tunnel sections, slope sections, and roadbed and pavement sections.

[0011] A road segment refers to a management unit within the mountainous expressway network, divided according to the expressway routes managed by each operating company; the structural points are distributed within the road segments.

[0012] The road network refers to the expressway network composed of various road segments;

[0013] S3. Multi-scale risk assessment coupling;

[0014] S4. Based on the assessment models at each scale, output the corresponding passage risk value and risk level.

[0015] Furthermore, the risk assessment dimension framework in step S1 includes basic risk dimensions, dynamic risk dimensions, and additional risk dimensions;

[0016] The basic risk dimension characterizes the inherent static risk of the assessment object;

[0017] The dynamic risk dimension represents external environmental risks that change dynamically over time and affect the probability or consequences of the occurrence of basic risks.

[0018] Additional risk dimensions characterize the control and event factors that have a suppressive or amplifying effect on risk.

[0019] Furthermore, the basic risk dimension includes at least one road natural attribute feature;

[0020] The basic risk factors of structural points include the natural disaster risk of structural points, technical conditions, and road structural characteristics, reflecting the inherent risks of structural points;

[0021] Basic risk factors for road sections include high-risk disaster structures within the road section, poor alignment characteristics of the road section, and traffic risks arising from adverse weather conditions.

[0022] Basic risk factors of the road network include the traffic risk of the road segments contained in the road network, as well as the impact of road network connectivity and road network density on the traffic risk of the road network.

[0023] Furthermore, the dynamic risk dimension includes at least one of meteorological conditions and traffic flow status;

[0024] Dynamic risk factors at structural points include weather conditions and traffic flow status;

[0025] The dynamic risk factor indicators for road sections include the longitudinal stability coefficient of traffic flow, the lateral stability coefficient of traffic flow, congestion, the proportion of large vehicles, and the frequency of various adverse weather warnings.

[0026] The indicators of dynamic risk factors in the road network include average saturation and traffic flow balance coefficient.

[0027] Furthermore, the additional risk dimension includes at least one factor that objectively occurs and has a suppressive or amplifying effect on the risk;

[0028] Structural point-specific control factors include infrastructure-specific control factors and traffic flow-specific control factors;

[0029] Additional risk factors for road sections include traffic accidents and road section characteristics.

[0030] Additional risk factors for road networks include two aspects: the speed of emergency response and the efficiency of emergency rescue.

[0031] Furthermore, the specific content of step S3 is as follows: Based on the multi-dimensional classification framework of "basic risk-dynamic risk-additional risk" and the multi-scale hierarchical framework of "structural point-road segment-road network", corresponding traffic risk assessment models are established for the three spatial scales, and they are coupled to form a three-layer integrated multi-scale multi-dimensional mountain expressway network traffic risk assessment system.

[0032] Among them, the assessment results of structural points are weighted and aggregated as part of the basic risks of road segments; the assessment results of road segments are weighted and aggregated as part of the basic risks of the road network.

[0033] The coupling process in step S3 is as follows:

[0034] I. Structural points;

[0035] The structural point access risk value is constructed by adjusting the basic risk value with dynamic risk factors and then correcting it with control factors. The calculation formula is as follows:

[0036]

[0037] In the formula, The value represents the traffic risk of the assessed structural point; n, m, and s are the number of basic risk indicators, dynamic risk indicators, and special control indicators included in the assessment, respectively. This serves as the baseline for background risk, used to avoid situations where the risk value is 0. This represents the quantified risk value of the i-th basic risk indicator. is the adjustment coefficient for the j-th dynamic risk indicator; This is the correction coefficient for the k-th specific control measure;

[0038] II. Road Section;

[0039] The basic risk of a road segment represents its inherent risk. It is based on the traffic risk at structural points, and then superimposed with risks from poor alignment characteristics and adverse weather conditions to arrive at the basic risk value of the road segment. The formula for calculating the basic risk value of a road segment is as follows:

[0040]

[0041] In the formula, This represents the basic risk value of the road segment corresponding to the i-th basic risk factor, and its value ranges from [0, 100]. This represents the original risk value of the i-th basic risk factor, including the traffic risk value of the structural point, the poor alignment characteristics of the road segment, and the adverse weather characteristics of the road segment;

[0042] The formula for calculating the traffic risk value of a road segment is as follows:

[0043]

[0044] In the formula, This represents the traffic risk value of the assessed road segment; The number of structural points and basic risk factors included in the road sections to be assessed; is the dynamic adjustment coefficient of the j-th traffic volume dynamic risk factor, used to reflect the amplification or reduction effect of dynamic factors on risk; The adjustment factor is for additional risk factors;

[0045] III. Road network;

[0046] The quantification of basic road network risk is based on the traffic risk of road segments, and the basic road network risk value is obtained by superimposing the road network connectivity and road network density.

[0047] The comprehensive risk value of a road segment is calculated using the following formula:

[0048]

[0049]

[0050] In the formula, R is the comprehensive traffic risk value of the entire road network, which is the weighted sum of the risks of each road segment; This indicates the total number of road segments in the road network; Let be the index of the road segment, representing the i-th road segment; Indicates the first Traffic risk value for this road section; Indicates the first Average hourly traffic volume of the road segment; Indicates the first The dynamic weighting coefficient of road segment i is determined by the proportion of traffic volume of road segment i to the total traffic volume of the road network. ; Indicates the first This section of road; Indicates the first Average hourly traffic volume of the road segment;

[0051] Basic risk value of road network The calculation formula is as follows:

[0052]

[0053] In the formula, The values ​​of various basic risk factors to be considered include the road segment traffic risk value. Road network connectivity Road network density The first fundamental risk Take directly The following Allocation is based on the remaining risk capacity and is carried out proportionally.

[0054] The road network traffic risk value is calculated using the following formula:

[0055]

[0056] in, Represents the road network traffic risk value; The number of basic risk indicators to be included in the assessment; Indicates the first The risk value of each basic risk indicator These constitute the basic risk values ​​of the road network, reflecting the inherent risk level of the road network structure; This is the dynamic risk adjustment coefficient for the road network. This is an additional risk correction factor.

[0057] Furthermore, the specific content of step S4 is as follows:

[0058] By inputting data from three dimensions—basic risk, dynamic risk, and additional risk—into the model system, the output yields quantitative traffic risk values ​​and corresponding risk levels at three scales: structural points, road segments, and road networks.

[0059] Risk level classification;

[0060] when When the value is greater than 100, the risk level is Level 1, which is a major risk and the acceptable level is unacceptable.

[0061] When 80 < When the value is ≤100, the risk level is Level 2, which is relatively high risk, and the acceptable level is not expected.

[0062] When 60 < When the risk level is ≤80, the risk level is Level 3, which is considered moderate risk, and the acceptable level is considered acceptable.

[0063] when When the risk level is ≤60, the risk level is level four, which is low risk and the acceptable level is acceptable.

[0064] Where P represents the traffic risk value of the corresponding structural point / road segment / road network.

[0065] Beneficial effects:

[0066] 1. This study investigated the "point-line-network" traffic risk assessment problem for mountainous expressways. "Point" traffic risk assessment helps to understand the traffic risk situation at high-risk locations such as bridge sections, tunnel sections, slope sections, and roadbed / pavement sections that are highly susceptible to geological disasters, providing a basis for customized infrastructure management strategies and effectively reducing the risk of single-point accidents. "Line" traffic risk assessment helps to identify potential risk points caused by weather, traffic, and alignment conditions, providing a basis for optimizing the layout of traffic safety facilities, adjusting enforcement points, and timely disseminating road condition information, effectively ensuring smooth and orderly traffic flow on road sections. "Network" traffic risk assessment helps to comprehensively assess the traffic situation of the road network, providing a basis for road network safety operation management and planning upgrades, effectively improving the safety and management efficiency of mountainous expressway operations.

[0067] 2. A multi-scale, multi-dimensional traffic risk assessment system that integrates structural points, road segments, and road networks, combining "basic risk, dynamic risk, and additional factors" is proposed. An indicator system and its quantitative method for assessing traffic risks at structural points, road segments, and road networks are established.

[0068] 3. By combining data on natural disasters, road infrastructure technical conditions, weather conditions, traffic flow, traffic accidents, and traffic control obtained through equipment sensing, maintenance inspections, and cross-departmental data dissemination, quantitative assessment of traffic risks at three scales—structural points, road sections, and road networks—was achieved.

[0069] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0070] Figure 1 Factors affecting the risk of passage through structural points;

[0071] Figure 2 Factors affecting traffic risk on the road section;

[0072] Figure 3 Factors affecting road network traffic risks;

[0073] Figure 4 A point-to-point network traffic risk assessment system for mountainous expressways;

[0074] Figure 5 A risk assessment system for highway traffic in mountainous areas;

[0075] Figure 6 Flowchart for quantifying the risks of passage through structural points;

[0076] Figure 7 Flowchart for quantifying traffic risks on road sections;

[0077] Figure 8 A flowchart for quantifying road network traffic risks. Detailed Implementation

[0078] To make the technical solutions, advantages, and objectives of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the protection scope of this application.

[0079] This invention provides a method for assessing traffic risks in mountainous expressway networks at multiple scales and dimensions, comprising the following steps:

[0080] S1: Construct a unified risk assessment framework for mountainous expressway networks. The framework includes basic risk dimensions, dynamic risk dimensions, and additional risk dimensions. The basic risk dimension represents the inherent static risk of the assessment object, the dynamic risk dimension represents the external environmental risks that occur dynamically over time and affect the probability or consequences of the basic risk, and the additional risk dimension represents the control and event factors that inhibit or amplify the risk.

[0081] I. The basic risk dimension includes at least one natural attribute characteristic of the road;

[0082] The basic risk factors of structural points include natural disaster risks (such as landslides, collapses, debris flows, water damage, etc.), technical conditions, and road structural characteristics (such as circular curves, longitudinal slopes, mainline entrances and exits, ramp alignment or sight distance, etc.), reflecting the inherent risks of structural points.

[0083] Basic risk factors for road sections include high-risk disaster structures within the road section, poor alignment characteristics of the road section, and traffic risks arising from adverse weather conditions.

[0084] The basic risk factors of the road network mainly include the traffic risk of the road segments contained in the road network, as well as the impact of road network structure such as road network connectivity and road network density on the traffic risk of the road network.

[0085] II. The dynamic risk dimension includes at least one of meteorological conditions and traffic flow status;

[0086] The dynamic risk factors of structural points include meteorological conditions (such as dense fog, water accumulation, icing, and crosswinds) and traffic flow conditions (such as average daily peak hour congestion, average daily proportion of large vehicles, operating speed V, and average daily peak hour vehicle speed dispersion D).

[0087] The dynamic risk factor indicators for road sections include the longitudinal stability coefficient of traffic flow, the lateral stability coefficient of traffic flow, congestion, the proportion of large vehicles, and the frequency of various adverse weather warnings.

[0088] The indicators of dynamic risk factors in the road network include average saturation and traffic flow balance coefficient.

[0089] III. Additional risk dimensions should include at least one factor that objectively occurs and has a suppressive or amplifying effect on the risk, such as control measures or historical events.

[0090] Structural point-specific control factors include infrastructure-specific control factors (such as whether emergency escape lanes, drainage devices, or safety warning signs are reasonably laid out) and traffic flow-specific control factors (such as speed monitoring, and control of passenger vehicles, dangerous goods vehicles, and freight vehicles).

[0091] Additional risk factors for road sections mainly include traffic accidents and road section attribute factors;

[0092] Additional risk factors for road networks mainly include two aspects: emergency response speed and emergency rescue efficiency.

[0093] S2: Based on the aforementioned unified risk assessment dimension framework, a vertically integrated risk assessment scale framework is established for the three spatial scales of structural points, road segments, and road networks; the structural points, road segments, and road networks refer to:

[0094] S2-1 Structural Point

[0095] Structural points refer to high-risk locations of bridge sections, tunnel sections, slope sections, and roadbed and pavement sections that are highly susceptible to geological disasters, as determined by the Ministry of Transport's "Technical Guidelines for Comprehensive Risk Assessment of Highway Disaster-Bearing Bodies in Natural Disasters" through the investigation of major disaster risks and hidden dangers on highways.

[0096] At the structural point scale, the factors affecting the traffic risk at structural points of mountainous expressways were analyzed, such as... Figure 1 As shown.

[0097] S2-2 section

[0098] A road segment refers to a section within a mountainous expressway network, defined according to the different expressway routes operated by various companies. The structural points are distributed within these road segments.

[0099] At the road segment level, the factors affecting traffic risk on mountainous expressway segments were analyzed, such as... Figure 2 As shown.

[0100] S2-3 road network

[0101] The road network refers to the expressway network composed of various road segments.

[0102] At the road network scale, the factors affecting traffic risks on mountainous expressway networks were analyzed, such as... Figure 3 As shown.

[0103] S3: Conduct multi-scale risk assessment coupling, wherein the basic risk at the road segment scale is at least partially based on the risk assessment results of the structural points it contains, and the basic risk assessment at the road network scale is at least partially based on the risk assessment results of the road segments it contains.

[0104] Road segments include structural points. When assessing the traffic risk of a road segment, the traffic risk value of the structural points is included as part of the basic risk of the road segment. If a road segment contains high-risk structural points, the road segment will be directly identified as a high-risk road segment. Similarly, in the road network assessment, the traffic risk value of the included road segments is included as part of the quantification of the basic risk of the road network. This achieves the unification of evaluation dimensions and the unification of quantification standards.

[0105] In step S3, the coupling method includes: weighting and aggregating the evaluation results of the lower-level scale (structural points) as part of the basic risk of the upper-level scale (road segments); and weighting and aggregating the evaluation results of the middle-level scale (road segments) as part of the basic risk of the top-level scale (road network).

[0106] The basic risk value of a road segment is obtained by integrating the traffic risk of structural points, the adverse alignment characteristics of the road segment, and the adverse weather characteristics of the road segment, and then weighting them.

[0107] The road network basic risk value is obtained by integrating the comprehensive road segment traffic risk value R, road network connectivity C, and road network density B, which are calculated from the road segment traffic risk value and then weighted.

[0108] Based on a multi-dimensional classification framework of "basic risk - dynamic risk - additional risk" and a multi-scale hierarchical framework of "structural point - road segment - road network", corresponding traffic risk assessment models are established for the three spatial scales, and these models are coupled to form a three-layered, multi-scale, multi-dimensional traffic risk assessment system for mountainous expressways. The mountainous expressway traffic risk assessment system is as follows: Figure 4 , 5 As shown.

[0109] The detailed coupling process is as follows:

[0110] The structural point access risk value is constructed by adjusting the basic risk value through dynamic risk factors, and then further correcting it through control factors. The structural point access risk quantification process is as follows: Figure 6 As shown; its calculation formula is as follows:

[0111]

[0112] Where P represents the traffic risk value of the assessed structural point; n, m, and s are the number of basic risk indicators, dynamic risk indicators, and special control indicators included in the assessment, respectively. This serves as the baseline for background risk, and its purpose is to avoid a risk value of 0. Referring to the "Guidelines for Traffic Safety Risk Assessment on Highways", the value is generally set at 5.0 for mountainous highways. Let i be the risk quantification value of the i-th basic risk indicator. This represents the total base risk value at this structural point. The addition reflects the cumulative effect of basic risks; Let j be the adjustment coefficient for the j-th dynamic risk indicator. The multiplication factor reflects the amplifying effect of weather and traffic flow on traffic risks; Let k be the correction coefficient for the k-th specific control measure. The multiplicative relationship reflects the inhibitory effect of control measures on traffic risks.

[0113] The basic risk of a road segment represents its inherent risk. It is based on the traffic risk at structural points, superimposed with risks from poor alignment characteristics and adverse weather conditions to arrive at the basic risk value of the road segment. The calculation formula is as follows:

[0114]

[0115] in, The basic risk factors to be considered include the traffic risk value of structural points, the poor alignment characteristics of road sections, and the adverse weather characteristics of road sections. To comprehensively consider the risk values ​​of each factor, an overall basic risk value within the range [0, 100] is obtained, avoiding excessive numerical inflation when multiple factors are superimposed. Therefore, the design logic of this formula is: the first basic risk... Take directly The following The remaining risk capacity (100 - allocated risk value) is allocated proportionally to reflect the competitive relationship and mutual influence among various structural points, highlighting the structural point with the highest risk.

[0116] The process for quantifying traffic risks on road sections is as follows: Figure 7 As shown; the formula for calculating the traffic risk value of a road segment is as follows:

[0117]

[0118] in, This represents the traffic risk value of the assessed road segment. The number of structural points and basic risk factors included in the road sections to be assessed. For the first section of the road The assessment risk value of each structural point or the basic risk factors of the road section. This represents the dynamic adjustment coefficient for dynamic risk factors related to traffic volume. This is a correction factor for additional risk factors.

[0119] The basic risk quantification of the road network is based on the traffic risk of road segments, and the basic risk value of the road network is obtained by superimposing the road network connectivity and road network density. In order to characterize the high risk of high traffic segments, this system uses the traffic volume of road segments as the basis for weight allocation, assigns higher weight coefficients to road segments with larger traffic volumes, and then uses the comprehensive value of the calculated traffic risk of road segments to represent the traffic risk of road segments in the calculation of the basic risk value of the road network.

[0120] The comprehensive risk value of a road segment is calculated using the following formula:

[0121]

[0122]

[0123] In the formula, R is the comprehensive risk value of road segment traffic. This indicates the total number of road segments contained in the road network; Indicates the first This section of road; Indicates the first Traffic risk value for this road section; Indicates the first Average hourly traffic volume of the road segment; Indicates the first The dynamic weighting coefficient for each road segment is determined by the proportion of traffic volume in that road segment to the total traffic volume of the road network. This ensures that the weights are normalized; Indicates the first This section of road; Indicates the first The average hourly traffic volume of this road segment.

[0124] Basic risk value of road network The calculation formula is as follows:

[0125]

[0126] In the formula, The values ​​of various basic risk factors to be considered include the road segment traffic risk value. Road network connectivity Road network density The first fundamental risk Take directly The following The remaining risk capacity (100 - allocated risk value) is allocated proportionally to reflect the interrelationship of various factors.

[0127] Road network traffic risk quantification process as follows Figure 8 As shown; the road network traffic risk value is calculated using the following formula:

[0128]

[0129] in, This represents the risk value of road network traffic. The number of basic risk indicators to be included in the assessment. Indicates the first The risk value of each basic risk indicator These constitute the basic risk values ​​of the road network, reflecting the inherent risk level of the road network structure. The road network dynamic risk adjustment coefficient reflects the real-time operation status of traffic flow, including average saturation and traffic balance coefficient, and is used to dynamically adjust basic risks. An additional risk correction coefficient is added to characterize the amplification or mitigation effect of emergency response capabilities on risks, including the 30-minute arrival rate and the 1-hour traffic recovery rate. This model comprehensively achieves a quantitative and systematic assessment of road network traffic risks through multiple layers of indicators.

[0130] S4: Based on the assessment models at each scale, output the corresponding passage risk value and risk level.

[0131] By inputting data from three dimensions—basic risk, dynamic risk, and additional risk—into the model system, the output yields quantitative traffic risk values ​​and corresponding risk levels at three scales: structural points, road segments, and road networks.

[0132] The passage risk level of the structural point is divided into four levels: Level 1, Level 2, Level 3, and Level 4, with Level 4 being the lowest and Level 1 being the highest. Based on the structural point risk value P, and referring to Table 1, the passage risk of this structural point is assessed.

[0133] Table 1 Classification of Risk Levels for Structural Points

[0134]

[0135] According to the "Guidelines for Highway Traffic Safety Risk Assessment", when some evaluation indicator values ​​reach the conditions in Table 2, the risk level is directly determined to be Level 1:

[0136] Table 2. Direct Judgment Criteria for Level 1 (Major Risk)

[0137]

[0138] The road segment traffic risk level is divided into four levels: Level 1, Level 2, Level 3, and Level 4, with Level 4 being the lowest and Level 1 being the highest. Table 3 shows the risk levels and corresponding risk degrees based on the road segment traffic risk value.

[0139] Table 3. Classification of Traffic Risk Levels for Road Sections

[0140]

[0141] Based on the road network traffic risk value, the road network traffic risk status is divided into four levels: Level 1 (major risk), Level 2 (relatively high risk), Level 3 (moderate risk), and Level 4 (low risk), in order to scientifically assess and differentiate the traffic risk level of the road network. Specific level classification threshold standards are detailed in Table 4 below.

[0142] Table 4. Classification of Road Network Traffic Risk Levels

[0143]

[0144] It is hereby declared that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for assessing traffic risks in mountainous expressway networks at multiple scales and dimensions, characterized in that, Includes the following steps: S1. Construct a unified framework for assessing traffic risks on mountainous expressway networks; S2. Based on the risk assessment dimension framework constructed in step S1, a vertically integrated risk assessment dimension framework is established for the three spatial scales of structural points, road segments, and road networks. Structural points refer to key locations that are highly susceptible to geological disasters. These are high-risk disaster locations identified through the Ministry of Transport's "Technical Guidelines for Comprehensive Risk Assessment of Highway Disaster-Bearing Bodies in Natural Disasters." Among these, key locations highly susceptible to geological disasters include bridge sections, tunnel sections, slope sections, and roadbed and pavement sections. A road segment refers to a management unit within the mountainous expressway network, divided according to the expressway routes managed by each operating company; the structural points are distributed within the road segments. The road network refers to the expressway network composed of various road segments; S3. Multi-scale risk assessment coupling; S4. Based on the assessment models at each scale, output the corresponding passage risk value and risk level.

2. The method for multi-scale, multi-dimensional assessment of traffic risk in mountainous expressway networks according to claim 1, characterized in that: The risk assessment dimension framework in step S1 includes basic risk dimension, dynamic risk dimension, and additional risk dimension. The basic risk dimension characterizes the inherent static risk of the assessment object; The dynamic risk dimension represents external environmental risks that change dynamically over time and affect the probability or consequences of the occurrence of basic risks. Additional risk dimensions characterize the control and event factors that have a suppressive or amplifying effect on risk.

3. The method for multi-scale, multi-dimensional assessment of traffic risk in mountainous expressway networks according to claim 2, characterized in that: The basic risk dimension includes at least one natural attribute feature of the road; The basic risk factors of structural points include the natural disaster risk of structural points, technical conditions, and road structural characteristics, reflecting the inherent risks of structural points; Basic risk factors for road sections include high-risk disaster structures within the road section, poor alignment characteristics of the road section, and traffic risks arising from adverse weather conditions. Basic risk factors of the road network include the traffic risk of the road segments contained in the road network, as well as the impact of road network connectivity and road network density on the traffic risk of the road network.

4. The method for multi-scale and multi-dimensional assessment of traffic risk in mountainous expressway networks according to claim 3, characterized in that: The dynamic risk dimension includes at least one of meteorological conditions and traffic flow status; Dynamic risk factors at structural points include weather conditions and traffic flow status; The dynamic risk factor indicators for road sections include the longitudinal stability coefficient of traffic flow, the lateral stability coefficient of traffic flow, congestion, the proportion of large vehicles, and the frequency of various adverse weather warnings. The indicators of dynamic risk factors in the road network include average saturation and traffic flow balance coefficient.

5. The method for multi-scale and multi-dimensional assessment of traffic risk in mountainous expressway networks according to claim 4, characterized in that: The additional risk dimension includes at least one factor that objectively occurs and has the effect of either suppressing or amplifying the risk; Structural point-specific control factors include infrastructure-specific control factors and traffic flow-specific control factors; Additional risk factors for road sections include traffic accidents and road section characteristics. Additional risk factors for road networks include two aspects: the speed of emergency response and the efficiency of emergency rescue.

6. The method for multi-scale, multi-dimensional assessment of traffic risk in mountainous expressway networks according to claim 5, characterized in that, The specific content of step S3 is as follows: Based on the multi-dimensional classification framework of "basic risk-dynamic risk-additional risk" and the multi-scale hierarchical framework of "structural point-road segment-road network", establish corresponding traffic risk assessment models for the three spatial scales, and couple them to form a three-layer integrated multi-scale multi-dimensional mountain expressway network traffic risk assessment system. Among them, the assessment results of structural points are weighted and aggregated as part of the basic risks of road segments; the assessment results of road segments are weighted and aggregated as part of the basic risks of the road network. The coupling process in step S3 is as follows: I. Structural points; The structural point access risk value is constructed by adjusting the basic risk value with dynamic risk factors and then correcting it with control factors. The calculation formula is as follows: In the formula, The value represents the traffic risk of the assessed structural point; n, m, and s are the number of basic risk indicators, dynamic risk indicators, and special control indicators included in the assessment, respectively. This serves as the baseline for background risk, used to avoid situations where the risk value is 0. This represents the quantified risk value of the i-th basic risk indicator. is the adjustment coefficient for the j-th dynamic risk indicator; This is the correction coefficient for the k-th specific control measure; II. Road Section; The basic risk of a road segment represents its inherent risk. It is based on the traffic risk at structural points, and then superimposed with risks from poor alignment characteristics and adverse weather conditions to arrive at the basic risk value of the road segment. The formula for calculating the basic risk value of a road segment is as follows: In the formula, This represents the basic risk value of the road segment corresponding to the i-th basic risk factor, and its value ranges from [0, 100]. This represents the original risk value of the i-th basic risk factor, including the traffic risk value of the structural point, the poor alignment characteristics of the road segment, and the adverse weather characteristics of the road segment; The formula for calculating the traffic risk value of a road segment is as follows: In the formula, This represents the traffic risk value of the assessed road segment; The number of structural points and basic risk factors included in the road sections to be assessed; is the dynamic adjustment coefficient of the j-th traffic volume dynamic risk factor, used to reflect the amplification or reduction effect of dynamic factors on risk; The adjustment factor is for additional risk factors; III. Road network; The quantification of basic road network risk is based on the traffic risk of road segments, and the basic road network risk value is obtained by superimposing the road network connectivity and road network density. The comprehensive risk value of a road segment is calculated using the following formula: In the formula, R is the comprehensive traffic risk value of the entire road network, which is the weighted sum of the risks of each road segment; This indicates the total number of road segments in the road network; Let be the index of the road segment, representing the i-th road segment; Indicates the first Traffic risk value for this road section; Indicates the first Average hourly traffic volume of the road segment; Indicates the first The dynamic weighting coefficient of road segment i is determined by the proportion of traffic volume of road segment i to the total traffic volume of the road network. ; Indicates the first This section of road; Indicates the first Average hourly traffic volume of the road segment; Basic risk value of road network The calculation formula is as follows: In the formula, The values ​​of various basic risk factors to be considered include the road segment traffic risk value. Road network connectivity Road network density The first fundamental risk Take directly The following Allocation is based on the remaining risk capacity and is carried out proportionally. The road network traffic risk value is calculated using the following formula: in, Represents the road network traffic risk value; The number of basic risk indicators to be included in the assessment; Indicates the first The risk value of each basic risk indicator These constitute the basic risk values ​​of the road network, reflecting the inherent risk level of the road network structure; This is the dynamic risk adjustment coefficient for the road network. This is an additional risk correction factor.

7. The method for multi-scale and multi-dimensional assessment of traffic risk in mountainous expressway networks according to claim 6, characterized in that, The specific content of step S4 is as follows: By inputting data from three dimensions—basic risk, dynamic risk, and additional risk—into the model system, the output yields quantitative traffic risk values ​​and corresponding risk levels at three scales: structural points, road segments, and road networks. Risk level classification; when When the value is greater than 100, the risk level is Level 1, which is a major risk and the acceptable level is unacceptable. When 80 < When the value is ≤100, the risk level is Level 2, which is relatively high risk, and the acceptable level is not expected. When 60 < When the risk level is ≤80, the risk level is Level 3, which is considered moderate risk, and the acceptable level is considered acceptable. when When the risk level is ≤60, the risk level is level four, which is low risk and the acceptable level is acceptable. Where P represents the traffic risk value of the corresponding structural point / road segment / road network.

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