A method for environmental impact assessment of online ride-hailing travel

Abstract

The present invention establishes an environmental impact assessment method for online car-hailing travel, which is used to evaluate the impact of online car-hailing travel on the traffic environment in an urban road network. From the perspective of network constraints and travel costs, the present invention establishes a ride-sharing network model that conforms to the characteristics of shared transportation in modern cities. The present invention proposes a traffic distribution problem based on section flow and an environmental cost function that conforms to the pollution characteristics of motor vehicles. The combination of the two can predict the flow situation and environmental impact of online car-hailing travel in an urban transportation network. Through the present invention, relevant departments can have a more detailed understanding of the impact of online car-hailing travel on the urban environment, so as to take timely and effective management measures, and provide strong support for the construction of sustainable modern urban transportation.

Description

Technical Field

[0001] The present invention relates to an environmental impact assessment method, and in particular to an environmental impact assessment method for online car-hailing travel. Background Art

[0002] With the advancement of motorization and urbanization, traffic problems in large and medium-sized cities in my country are becoming increasingly serious. Among them, environmental pollution has always been an important issue of concern to traffic managers and urban residents. In recent years, with the rapid development of mobile communication technology, shared travel modes such as online car-hailing and ride-sharing have become one of the main ways for urban residents to travel. Many studies have shown that since the starting and ending points of drivers and passengers are the same, drivers do not need to take detours to pick up and drop off passengers, and ride-sharing travel can effectively reduce environmental pollution in urban road networks. However, in online car-hailing travel, there are differences in the starting and ending points of drivers and passengers. Drivers may incur additional environmental costs when taking detours to pick up and drop off passengers. Therefore, the impact of online car-hailing on the traffic environment is difficult to determine.

[0003] A method for evaluating the impact of motor vehicle exhaust emissions on human health (application number 202110261830.X), which establishes a database based on traffic data, motor vehicle data, meteorological data and health data of the area to be evaluated, and on this basis, uses a pollutant diffusion distribution model to calculate pollutant concentration data, and uses a population pollutant exposure model to calculate population pollutant exposure parameters, thereby establishing a health risk assessment model to quantify the impact of motor vehicle exhaust emissions on human health. A method for evaluating urban traffic operation based on ecological index (application number 201911419439.7), which defines the minimum directed section and ecological cost in the urban road network, calculates the ecological index of the minimum directed section, directed path, and directed path set in the urban road network, and uses this as a basis to optimize and adjust the urban traffic operation plan to improve urban traffic. Both of these existing inventions take into account the sustainable development of urban transportation systems, but neither takes into account emerging shared travel modes. Summary of the invention

[0004] Technical problem: The present invention provides a method for evaluating the environmental impact of online ride-hailing travel in an urban road network, establishes a ride-sharing network model that conforms to the characteristics of shared transportation in modern cities, and predicts the traffic flow of online ride-hailing travel in an urban transportation network based on the model. On this basis, the present invention designs an environmental cost function based on the pollution characteristics of motor vehicles to predict and evaluate the impact of online ride-hailing travel on the environment in an urban road network. . This method can help relevant departments to better understand the impact of online ride-hailing travel on the urban environment and take timely and effective measures, thereby providing strong support for building sustainable modern urban transportation.

[0005] Technical solution: The present invention provides an environmental impact assessment method for online car-hailing travel, which includes the following process:

[0006] 1) Based on the existing urban road network, build a ridesharing network model that conforms to the characteristics of modern urban shared transportation. The specific process is as follows:

[0007] Step 1: Obtain and input the topological structure, travel mode and travel demand of the urban road network.

[0008] The topological structure (N, A) of the urban road network, including the connection status and specific information of the directed road segments a∈A and the nodes n∈N, can be obtained by consulting the map. Among them, A is the set of directed road segments, and N is the set of road nodes. The topological structure of the urban road network can be stored in the software through adjacency matrix, adjacency table, etc.

[0009] According to the characteristics of shared transportation in modern cities, the travel modes in the urban road network are divided into three parts: solo driver (SD), ridesharing driver (SD) with passengers in the car, and rider (R). I represents the set of travel modes, SD represents the set of solo drivers, RD represents the set of ridesharing drivers with passengers in the car, and R represents the set of riders. I = SD∪RD∪R. Within the sets SD, RD, and R, the travel modes may be further divided according to the specific conditions of the passengers riding the ridesharing car.

[0010] Travel demand in urban road networks w It occurs at the starting point and ends at the destination. The set of starting and ending points are represented by O and D respectively. The starting and ending points with travel demand form the OD pair w∈W in the network.

[0011] Step 2: Establish traffic flow constraints and ride-sharing matching constraints that are consistent with the travel characteristics of online ride-hailing.

[0012] ① Traffic flow constraints

[0013] The traffic flow in the urban road network can be expressed as:

[0014]

[0015]

[0016]

[0017] Where x a，i represents the flow of travel mode i on road segment a; represents the flow of travel mode i between OD pair w on road segment a; Represents the flow between OD pair w on section a.

[0018] OUT(·) represents the set of directed road segments starting from a certain node, and IN(·) represents the set of directed road segments ending at a certain node. For the starting point o∈O and the end point d∈D in the urban road network, we have:

[0019]

[0020]

[0021] For the non-originating and non-destination road nodes n∈N\O,D in the urban road network, we have:

[0022]

[0023] At road nodes that are not the starting or ending points, there is the following flow relationship:

[0024]

[0025] Where N\O, D represents the set of road nodes that are not the starting and ending points.

[0026] ② Ride-sharing matching constraints

[0027]

[0028] Where Γ r (i) represents mapping the online car-hailing driver i∈RD to the corresponding online car-hailing passenger, i.e., Γ r :RD→R,N i Indicates the number of passengers in the car of online car-hailing driver i.

[0029] Step 3: Calculate the travel costs of travelers in the urban road network.

[0030] According to the characteristics of shared transportation in modern cities, the travel costs of travelers are mainly divided into three parts: time cost, inconvenience cost and carpooling fee.

[0031]

[0032] The road flow vector represents the travel cost of a traveler of mode i between OD pairs w on road segment a, which is a function of x; represents the travel time of travelers on road section a, function t a (·)about Strictly monotonically increasing empirical function; α i represents the time value of travel mode i, βi represents the inconvenience coefficient of travel mode i; B a，i represents the basic fee collected (paid) by online car-hailing driver i∈RD (online car-hailing passenger i∈R) on road section a; m i Represents the price floating parameter of travel mode i.

[0033] The ridesharing network model consists of the topological structure, travel mode and travel demand in step 1, the constraints in step 2 and the travel cost in step 3.

[0034] 2) Based on the equilibrium principle of ride-hailing users, a variational inequality model is established to predict the flow of online ride-hailing travel in the urban transportation network.

[0035] Find x * ∈Ω RUE Satisfy the formula:

[0036]

[0037] Where Ω RUE represents the feasible set of x, that is, the set of road flow that satisfies the traffic flow constraints and the ride-sharing matching constraints; the travel cost vector c(x * ) means x=x * The value of c(x) when .

[0038] The solution process of the above variational inequality model can use existing solvers, such as the PATH solver of the software GAMS; or use a suitable convergence algorithm, such as the adaptive projection algorithm. Through the solution, the flow distribution of the urban road network in the equilibrium state is predicted.

[0039] 3) Establish an environmental cost function to predict the impact of online ride-hailing travel on the urban environment.

[0040] According to the pollution characteristics of motor vehicles and combined with existing research literature, the following environmental cost function is established:

[0041] T EC (x) = e(x) T V(x)

[0042]

[0043] Where T EC (x) represents the environmental cost of the entire urban road network, which is a function of x; represents the environmental cost vector in the urban road network, e a (·) represents the environmental cost generated on road section a, which is a function of x; L arepresents the length of section a. In actual operation, the free flow travel time t can be measured by the floating car method. a,0 , and according to the free flow speed v of the floating car a,0 And the formula L s =v a,0 t a,0 Calculate. V(x) represents the motor vehicle flow vector in the urban road network, that is, the sum vector of the empty vehicle driver flow and the online car-hailing driver flow.

[0044] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0045] The present invention provides an environmental impact assessment method for online car-hailing travel, predicts the flow distribution of the urban road network under the equilibrium state of shared users, and designs an environmental cost function based on the pollution characteristics of motor vehicles, which is used to evaluate the impact of online car-hailing travel in the urban road network on the environment. By using the present invention, relevant departments can more clearly understand the impact of online car-hailing travel on the urban environment, so as to take timely and effective management measures and build a modern urban transportation system with sustainable development. The present invention has the following advantages: ① Innovatively studies the impact of online car-hailing travel on the urban environment. Since the starting and ending points of drivers and passengers are inconsistent, the research difficulty is increased and more challenging; ② Establishes an environmental cost function that conforms to the characteristics of urban shared transportation, and quantifies the impact of travel modes on the urban road environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a flow chart of the method of the present invention;

[0047] Figure 2 is the topological structure of the target city road network. DETAILED DESCRIPTION

[0048] The present invention will be further described below in conjunction with examples and accompanying drawings.

[0049] The present invention provides an environmental impact assessment method for online car-hailing travel, such as Figure 1 As shown, the following process is included:

[0050] 1) Based on the target city road network, build a ridesharing network model that meets the characteristics of modern urban shared transportation. The specific process is as follows:

[0051] Step 1: Obtain and input the topological structure, travel mode and travel demand of the target city road network.

[0052] Based on the geographical location and traffic elements, the target city area is divided into multiple traffic zones. Each traffic zone can be used as the starting point or the end point of a traffic trip. The set of starting and ending points are represented by O and D respectively. The starting and ending points with travel demand form OD pairs w, and the set of OD pairs in the network is represented by W. There is a travel demand q between OD pairs w. w .

[0053] By consulting the map, the topological structure (N, A) of the target city road network is obtained. Each traffic zone is a node in the topological structure, represented by n. The set of nodes is represented by N. The urban roads connecting each traffic zone are directed sections in the topological structure, represented by a. The set of directed sections is represented by A. The topological structure of the urban road network can be stored by adjacency matrix, adjacency table, etc.

[0054] Travel demand w It can be obtained through traditional methods such as travel demand surveys and OD demand inversion, as well as emerging methods such as intelligent traffic monitoring systems, mobile phone signaling and GPS.

[0055] The travel mode in the target city road network is denoted by i. The set of travel modes is denoted by I. The travel modes in the network include an empty car driver driving alone, a ride-hailing driver with passengers in the car, and a ride-hailing passenger riding in a ride-hailing car, denoted by i∈SD, i∈RD, and i∈R, respectively.

[0056] After sorting, the topological structure of the target city road network is as follows: Figure 2 As shown in Table 1, there are 24 nodes, 76 road segments, and 528 OD pairs in this road network. The travel modes in this road network are shown in Table 1.

[0057] Table 1 Travel modes of target city road network

[0058]

[0059] Step 2: Establish traffic flow constraints and ridesharing matching constraints that are consistent with the characteristics of shared travel.

[0060] ① Traffic flow constraints

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068] ② Ride-sharing matching constraints

[0069]

[0070] Step 3: Calculate the travel costs of travelers in the target city’s road network.

[0071] Through preliminary investigation, the values ​​of various parameters in the target city road network are shown in Table 2.

[0072] Table 2 Parameters of target city road network

[0073]

[0074] The travel cost in the target road network is calculated as follows:

[0075]

[0076] The specific calculation function is:

[0077]

[0078] Where t a,0 is the free flow travel time of section a, which can be obtained by the floating car method; a is the capacity of section a, which can be obtained by visiting the design unit or consulting relevant information.

[0079] 2) Based on the equilibrium principle of ride-hailing users, a variational inequality model is established to predict the flow of online ride-hailing travel in the urban transportation network.

[0080] Find x * ∈Ω RUE Satisfy the formula:

[0081]

[0082] Ω RUE represents the feasible set of x, that is, the set of road flow that satisfies the traffic flow constraints and the ride-sharing matching constraints. The travel cost vector c(x * ) means x=x * The value of c(x) when .

[0083] The adaptive projection algorithm is used to solve the variational inequality. Table 3 gives m i=0.1, the traffic distribution of the target city road network under the equilibrium state of carpooling users.

[0084] Table 3 Traffic distribution of target city road network

[0085]

[0086] 3) Establish an environmental cost function to evaluate the impact of online ride-hailing travel on the target city’s environment.

[0087] Obtaining the free-flow travel time t by the floating car method a,0 , calculate the length of the road section L a =v a,0 t a,0 , where v a,0 is the free flow speed, which is 60km / h. Based on the pollution characteristics of motor vehicles and the existing research literature, the following environmental cost function is established:

[0088] T EC (x) = e(x) T V(x)

[0089]

[0090] Table 4 gives the m i The impact of online ride-hailing trips on the target city environment with different values ​​is compared with the traditional user equilibrium state (i.e., there is no online ride-hailing trip in the urban road network, and there are only empty car drivers SD).

[0091] Table 4 Environmental impact of online ride-hailing travel on the road network of target cities

[0092]

[0093] From Table 4, we can see that when m i = 0.1 and m i =0.05, online car-hailing has a certain negative impact on the environment of the target city's road network; and m i =0.01, online ride-hailing has improved the road network environment in the target city.

[0094] The present invention also provides an environmental impact assessment device for online car-hailing travel, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned environmental impact assessment method for online car-hailing travel when executing the computer program.

[0095] The present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned method for environmental impact assessment of online ride-hailing travel.

[0096] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0097] The above embodiments are only preferred implementation modes of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and equivalent substitutions without departing from the principles of the present invention. These technical solutions after improvements and equivalent substitutions to the claims of the present invention all fall within the protection scope of the present invention.

Claims

1. A method for evaluating the environmental impact of online car-hailing travel, characterized in that: The method comprises the following steps: 1) Based on the urban road network, a ridesharing network model that meets the characteristics of urban shared transportation is constructed; 2) Based on the equilibrium principle of ride-sharing users, a variational inequality model is established to predict the traffic flow of the urban transportation network for online ride-hailing travel; 3) Establish an environmental cost function to evaluate the impact of online ride-hailing on the urban environment. The greater the environmental cost, the greater the impact on the urban environment. The environmental cost function established in step 3) is: T EC (x)=e(x) T V(x) Where T EC (x) represents the environmental cost of the entire urban road network, which is the road flow vector The function of represents the flow of travel mode i between OD pairs w on road segment a, w∈W, W represents the set of OD pairs in the urban road network; represents the environmental cost vector in the urban road network, e a (·) represents the environmental cost generated on road section a, which is a function of x. L a represents the length of road section a; V(x) represents the motor vehicle flow vector in the urban road network, that is, the sum vector of the empty vehicle driver flow and the online car-hailing driver flow.

2. The environmental impact assessment method for online car-hailing travel according to claim 1 is characterized in that: The specific process of step 1) is as follows: Step 1: Obtain the topological structure, travel mode and travel demand of the urban road network The topological structure of the urban road network is (N, A), where A is the set of directed road segments and N is the set of road nodes; The set of travel modes in the urban road network is I = SD∪RD∪R, where SD represents the set of drivers whose travel mode is to drive alone in an empty car, RD represents the set of online car-hailing drivers whose travel mode is to have passengers in the car, and R represents the set of online car-hailing passengers whose travel mode is to take online car-hailing cars. Travel demand on the urban road network w It occurs at the starting point and ends at the end point. The set of the starting point and the end point are represented by O and D respectively. Step 2: Establish traffic flow constraints and ride-sharing matching constraints that meet the travel characteristics of online ride-hailing ① Traffic flow constraints are expressed as: Where x a,i represents the flow of travel mode i on road segment a; represents the flow between OD pair w on section a; For the starting point o∈O and the end point d∈D in the urban road network, we have: Where OUT(·) represents the set of directed segments starting from "·", and IN(·) represents the set of directed segments ending at "·". For road nodes that are not starting or ending points in the urban road network, there are: Where N\O,D represents the set of road nodes that are not the starting and ending points; At road nodes that are not the starting or ending points, there is the following flow relationship: ② The carpool matching constraint is expressed as: Where Γ r (i) represents mapping the online car-hailing driver i to the corresponding online car-hailing passenger, that is, Γ r :RD→R,N i Indicates the number of passengers in the car of online car-hailing driver i; Step 3: Calculate the travel costs of travelers in the urban road network According to the characteristics of urban shared transportation, the travel cost of travelers includes time cost, inconvenience cost and ride-sharing fee, which can be expressed as: In the formula represents the travel cost of a traveler of mode i between OD pairs w on road segment a, which is a function of x; represents the travel time of travelers on road section a, function t a (·) is about Strictly monotonically increasing empirical function; α i represents the time value of travel mode i, β i represents the inconvenience coefficient of travel mode i; B a,i represents the basic fee collected / paid by online car-hailing driver i / online car-hailing passenger i on road section a; m i represents the price fluctuation parameter of travel mode i; Step 4: The ridesharing network model consists of the topological structure, travel mode and travel demand in step 1, the constraints in step 2 and the travel cost in step 3.

3. The environmental impact assessment method for online car-hailing travel according to claim 2 is characterized in that: The specific details of step 2) are as follows: Find x * ∈Ω RU Satisfy the formula: Where Ω RUE represents the feasible set of x, that is, the set of road flow that satisfies the traffic flow constraints and the ride-sharing matching constraints; the travel cost vector c(x * ) means x=x * The value of c(x) when .

4. An environmental impact assessment device for online car-hailing travel, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the environmental impact assessment method for online ride-hailing travel described in any one of claims 1 to 3 are implemented.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the environmental impact assessment method for online ride-hailing travel described in any one of claims 1 to 3 are implemented.

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