CN108985616A - A kind of public transportation lane evaluation of layout method - Google Patents

Abstract

The invention discloses a method for evaluating the layout of bus-only lanes, which comprises the following steps: step 1, calculating the reduction rate of per capita travel time after the bus-only lane layout through the per capita travel time before and after the bus-only lane layout; step 2, establishing the layout of bus lanes The running speed of cars and buses before the dedicated lane; step 3, establish the running speed of cars and buses after laying the dedicated bus lane; step 4, according to the parameters obtained in step 1-step 3, establish a dedicated The comprehensive evaluation model after road layout is used to evaluate the layout of bus lanes. The method starts from the perspective of per capita travel time and vehicle running speed, analyzes a series of indicators before and after the establishment of dedicated bus lanes, and finally establishes a comprehensive evaluation model to evaluate the setting effect of dedicated lanes, which has broad application prospects.

Description

A method for evaluating the layout of bus-only lanes

technical field

The invention relates to the field of transportation, in particular to a method for evaluating the layout of bus lanes.

Background technique

With the continuous growth of the number of motor vehicles, traffic congestion is spreading in most cities, which has a certain impact on the development of urban transportation and the quality of life of residents, thus restricting the sustainable development of cities. Buses have the characteristics of high passenger capacity. Vigorously developing bus travel can reduce the waste of traffic resources, reduce traffic congestion, reduce environmental pollution, and save energy and land resources to a certain extent. In the actual traffic road network, the large-scale popularity of cars has become an obstacle to the operation of buses in the road network. The service level of buses cannot meet the expectations of travelers, which gradually reduces the attractiveness of buses.

Under the above circumstances, a series of "transit priority" strategies have been launched to promote the development of public transport. Road resources in cities are limited, and conditional allocation of road resources, that is, setting up bus-only lanes, is one of the important methods to implement "Bus Priority". Under the guidance of the "Bus Priority" strategy, major cities are increasing the mileage of bus-only lanes in order to achieve the effect of forming a network of dedicated lanes and improving their coverage. However, the exclusive use of road resources by buses on the dedicated lanes will cause more congestion to a certain extent. From the perspective of the overall travel effect of the transportation network, the advantages of setting up dedicated bus lanes may not necessarily outweigh the disadvantages. The establishment of bus lanes can produce some unquantifiable social benefits, which may not be reflected in a short period of time, but these social benefits are still very important in the long run. Therefore, it is necessary to evaluate the bus-only layout.

Contents of the invention

The purpose of the present invention is to address the deficiencies in the prior art and provide a method for evaluating the layout of bus-only lanes, considering the bus-only lanes in the form of marking and isolation, and analyzing the setting of bus-only lanes from the perspective of per capita travel time and vehicle speed A series of indicators before and after, and finally establish a comprehensive evaluation model to evaluate the setting effect of special lanes.

The purpose of the present invention can be achieved through the following technical solutions:

A method for evaluating the layout of bus lanes, said method comprising the following steps:

Step 1. Through the per capita travel time before and after the bus-only lane layout, calculate the reduction rate of per capita travel time after the bus-only lane layout;

Step 2, establish the running speed of cars and buses before laying out bus lanes;

Step 3. Establish the running speed of cars and buses after the dedicated bus lane is arranged;

Step 4. According to the parameters obtained in steps 1-3, establish a comprehensive evaluation model after the bus lane layout, and evaluate the bus lane layout.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

The present invention carries out several specific indicators of the average running speed of cars and buses in mixed traffic before the bus lane is laid out, and the average speed of cars and buses after the bus lane is laid out by selecting the reduction rate of travel time per capita, and the bus lane is laid out. Evaluation, more comprehensively reflects the road performance, and provides a reasonable basic data source for the comprehensive evaluation model. Based on the above-mentioned specific indicators, a comprehensive evaluation model is established to evaluate the effect of the dedicated lane from an overall perspective, which can reflect the setting of the dedicated lane Whether it is scientific, and provide a reference for whether to build bus-only lanes on similar roads.

Description of drawings

Fig. 1 is a flowchart of a method for evaluating the layout of bus lanes according to an embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example:

The present embodiment provides a method for evaluating the layout of bus-only lanes, the flow chart of the method is as shown in Figure 1, and includes the following steps:

Step 1. Through the per capita travel time before and after the bus-only lane layout, calculate the reduction rate of per capita travel time after the bus-only lane layout; the calculation formula of the per capita travel time is as follows:

in, Indicates the number of travelers using cars on road section a, Indicates the travel time of traveling by car; Indicates the number of travelers using buses on road segment a, Indicates travel time by bus;

The formula for calculating the reduction rate of travel time per capita after the layout of the dedicated lanes is as follows:

Among them, T′ _A represents the per capita travel time before the bus lane is laid out, and T _A represents the per capita travel time after the bus lane is built.

Step 2. Establish the running speed of cars and buses before laying out bus-only lanes; the formula for the running speed of cars before laying out bus-only lanes is as follows:

in, Indicates the average running speed of cars in mixed traffic; Indicates the free flow speed of the car, which is related to the road grade and the number of lanes; Indicates the flow value of cars on road section a; Indicates the traffic flow value of the bus on road section a; Indicates the number of travelers using cars to travel on road section a; Indicates the number of travelers using buses on road section a; η ^c represents the flow conversion coefficient of cars; η ^b represents the flow conversion coefficient of buses; c _s represents the actual traffic capacity of the road section, which is obtained by modifying the theoretical traffic capacity, The correction formula is c=r ₁ ×r ₂ ×r ₃ ×C, where C represents the theoretical traffic capacity of a single lane, r ₁ represents the correction coefficient for the lane width, r ₂ represents the correction coefficient for the number of lanes, and r ₃ represents the street-oriented correction coefficient for road sections;

The formula for the bus running speed before the bus-only lane is laid out is as follows:

in, Indicates the average running speed of the bus in mixed traffic; Indicates the free-flow speed of the bus, which is related to the road grade and the number of lanes.

Step 3. Establish the running speed of cars and buses after the dedicated bus lane is arranged;

The experimental data shows that after setting up the bus lane, if the saturation of the bus is lower than 0.3, the operation of the bus will not cause interference to the car, and the speed of the car will not decrease due to the increase of the saturation of the bus. :

After the bus-only lane is laid out, if the saturation of the bus is not greater than 0.3, the formula for the running speed of the car is as follows:

in, Indicates the average running speed of cars after bus lanes are laid, Indicates the traffic capacity of cars on road section a;

If the saturation of the bus on the road section is greater than 0.3, when the running speed of the bus in front is slow, the bus will choose to occupy the ordinary lane when it needs to overtake, which will affect the operation of the car. When the saturation of the bus is high, the speed of the car is not only related to its own saturation but also to the saturation of the bus due to the influence of the driver's psychological factors. Therefore:

After the bus lane is laid out, if the saturation of the bus is greater than 0.3, the formula for the running speed of the car is as follows:

Among them, the saturation of the bus

The actual data shows that if the saturation of the car is lower than 0.5, the operation of the bus will hardly be affected by the car, so:

After the bus-only lane is laid out, if the saturation of the car is not greater than 0.5, the formula for the bus running speed is as follows:

in, Indicates the average running speed of the bus after the bus lane is laid out;

If the saturation of the car on the road section is higher than 0.5, the increase of the saturation of the car will reduce the calculated running speed of the bus to a certain extent. In this case, the running speed of the bus is not only related to its own saturation It is also related to the saturation of the car, so:

After the bus-only lane is laid out, if the saturation of the car is greater than 0.5, the formula for the bus running speed is as follows:

Among them, the saturation of the car Indicates the traffic capacity of buses on section a.

Step 4. According to the parameters obtained in steps 1-3, establish a comprehensive evaluation model after the bus lane layout, and evaluate the bus lane layout.

When establishing a comprehensive evaluation model, set the index system as X, any x _i , x _j ∈ X, if x _i is related to x _j , it means that x _i can be explained by x _j , and the higher the degree of correlation, x _i is explained by x _j The more explanations are made, the less independent xij is, and the smaller the role in the index system is, assuming that there are n sequences and p indexes in the index system X, then xij is the jth index of the _i -th sequence , the following evaluation indicators are used in this comprehensive evaluation model: per capita travel time reduction rate ΔT, average running speed of cars in mixed traffic before bus lanes are laid The average running speed of buses in mixed traffic before bus lanes are laid The average running speed of cars after bus lanes are laid The average running speed of the bus after the bus lane is laid That is, p=5, the sequence number n is the number of road sections, there is The steps to determine the weight by the correlation coefficient method are as follows:

a. The conversion of indicators with the trend: when there are forward and reverse indicators coexisting, the reverse indicators should be forwarded first. The method of forwarding the reverse indicators is as follows:

In the formula, i=1,2,...,n, j=1,2,...,p;

b. Dimensionless indicators: Different evaluation indicators often have different dimensions and dimensional units. In order to eliminate this effect, each evaluation indicator is dimensionless by using the mean value method, as follows:

After averaging, the mean of each index is 1, and its variance is:

That is, the variance of each index after meanization is the coefficient of variation of each index The square of , which retains the information of the degree of variation of each index;

c. Calculation of correlation coefficient: The formula for calculating the correlation coefficient between indicators in the indicator system is as follows:

Among them, L _ii represents the correlation between index i and index i, L _jj represents the correlation between index j and index j, L _ij represents the correlation between index i and index j, r _ij represents the normalized index i and index j The correlation coefficient of , y _i represents the dimensionless value of index i, and y _j represents the dimensionless value of index j;

d. Calculate the mean value of the degree of correlation between the index x _j and other indexes:

e. Reverse the average correlation degree:

f. Calculate the weight of the index x _j :

g. Calculate the comprehensive score: Use the weight ω _j to carry out weighted summation on the dimensionless indicators, and the calculation formula of the comprehensive evaluation value D _i is as follows:

The above is only a preferred embodiment of the patent of the present invention, but the scope of protection of the patent of the present invention is not limited thereto. The equivalent replacement or change of the technical solution and its invention patent concept all belong to the protection scope of the invention patent.

Claims (5)

1. A bus lane layout evaluation method is characterized by comprising the following steps:

step 1, calculating to obtain the reduction rate of the average pedestrian travel time after the bus lane layout through the average pedestrian travel time before and after the bus lane layout;

step 2, determining the running speed of the car and the running speed of the bus before the bus lane is laid;

step 3, determining the running speed of the cars and the running speed of the buses after the bus lanes are laid;

and 4, establishing a comprehensive evaluation model after the bus lane layout according to the parameters obtained in the steps 1 to 3, and evaluating the bus lane layout.

2. The method for evaluating the layout of the bus lanes according to claim 1, wherein the calculation formula of the average time of travel of people in step 1 is as follows:

wherein,representing the number of travelers on the section a who travel using cars,representing the travel time of using the car;representing the number of travelers on the road segment a who travel using the bus,representing the travel time of using the bus for travel;

the calculation formula of the reduction rate of the average human-out line time after the layout of the special lane is as follows:

wherein, T'_ARepresents the average time of travel, T, before the bus lane is laid_AAnd the average trip time of people after the bus lane is laid is shown.

3. The bus lane layout evaluation method according to claim 1, characterized in that: in step 2, the formula of the running speed of the car before the bus lane is laid is as follows:

wherein,representing the average running speed of the car in the mixed running process;representing the free flow speed of the car, the value is related to the road grade and the number of lanes;the flow value of the car on the road section a is represented;representing the flow value of the bus on the road section a;representing the number of travelers on the section a who use cars to travel;representing the number of travelers on the road section a using the bus to travel, eta^crepresenting the flow conversion coefficient of the car [. eta. ]^bRepresenting a flow conversion coefficient of the bus; c. C_sThe actual traffic capacity of the road section is represented by correcting the theoretical traffic capacity, and the correction formula is that c is r₁×r₂×r₃X C, C represents the theoretical traffic capacity of a single lane, r₁Indicates a lane width correction coefficient, r₂Represents a lane number correction coefficient; r is₃Representing road section street correction coefficients;

the bus running speed formula before the bus lane is laid is as follows:

wherein,representing the average running speed of the bus during mixed running;the free flow speed of the bus is represented, and the value is related to the road grade and the number of lanes.

4. The method for evaluating the layout of the bus lanes as claimed in claim 1, wherein in step 3, after the bus lanes are laid, if the saturation of the bus is not more than 0.3, the formula of the running speed of the car is as follows:

wherein,represents the average running speed of the cars after the bus lane is laid,representing the traffic capacity of the cars on the section a;

after the bus lane is laid, if the saturation of the bus is greater than 0.3, the car running speed formula is as follows:

wherein, the saturation of the bus

After the bus lane is laid, if the saturation of the car is not more than 0.5, the bus running speed formula is as follows:

wherein,the average running speed of the bus after the bus lane is laid is represented;

after the bus lane is laid, if the saturation of the car is greater than 0.5, the bus running speed formula is as follows:

wherein the saturation of the car Representing the capacity of the bus on the road segment a.

5. The method for evaluating the layout of public transport lanes as claimed in any one of claims 1 to 4, wherein in the step 4, when the comprehensive evaluation model is established, the index system is set to X, and any X is set_i、x_jE.g. X, if X_iAnd x_jCorrelation, then x is illustrated_iCan be x_jExplained, the higher the degree of correlation, x_iIs x by_jThe more interpretations, x_iThe less independent, the less effective the index system, assuming n sequences, p indices are present in index system X, then X_ijThat is, the j index of the i sequence, the following evaluation indexes are used in the comprehensive evaluation model: the reduction rate delta T of the time of all people going out and the average running speed of the cars during mixed running before the arrangement of the bus laneAverage running speed of bus during mixed running before bus lane layingAverage running speed of cars after bus lane layingAverage running speed of bus after bus lane layoutThat is, p is 5, and the number of sequences n is the number of links, thereThe steps of determining the weight by the correlation coefficient method are as follows:

a. and (3) performing homotrending transformation on indexes: when the forward index and the reverse index coexist, the reverse index should be forward-converted, and the forward-conversion method of the reverse index is as follows:

wherein i is 1,2, …, n, j is 1,2, …, p;

b. nondimensionalization of indexes: different evaluation indexes often have different dimensions and dimension units, and in order to eliminate the influence, each evaluation index is subjected to non-dimensionalization processing by using an averaging method as follows:

the mean value of each index after the averaging is 1, and the variance is as follows:

that is, the variance of each index after the averaging is the coefficient of variation of each indexThe square of (2), which retains the information of the degree of variation of each index;

c. calculation of correlation coefficient: the calculation formula of the correlation coefficient among the indexes in the index system is as follows:

wherein L is_iiIndicates the correlation between index i and index i, L_jjIndicates the correlation between the index j and the index j, L_ijIndicates the correlation between index i and index j, r_ijRepresents the correlation coefficient, y, of the index i normalized to the index j_iIndicates a dimensionless value of the index i, y_jRepresenting a dimensionless value of the index j;

d. calculating the index x_jMean of the degree of correlation with other indices:

e. the average degree of correlation is inverted:

f. computingIndex x_jThe weight of (c):

g. calculating a comprehensive score: using the weight omega_jWeighting and summing the dimensionless indexes to obtain a comprehensive evaluation value D_iThe calculation formula is as follows: