阅读说明：本技术 一种利用公路数据快速建立Vissim仿真路网的方法 (Method for quickly establishing Vissim simulation road network by using road data ) 是由 熊子瑜 白宇 黄炎 王欣南 望开潘 陈中治 刘东升 丁璁 于 2021-08-24 设计创作，主要内容包括：本发明公开了一种利用公路数据快速建立Vissim仿真路网的方法,步骤是：S1、加载道路设计软件的SDB项目文件项目文件,解析路线平纵、设计速度、横断面、分流区、合流区、平交范围、线位承接关系；S2、根据路幅情况、分合流、平交口将路段拆分为一般路段和特殊路段；S3、进行路段转换,包括行车道结构解析及行车道数据解析两个部分,行车道结构解析指在路段内部分情况转换成符合Vissim路段及连接器组合而成的数据结构；S4、将转换完成的一般路段和特殊路段输出成可扩展标记语言,结合模板生成Vissim能直接使用的项目文件。方法易行,操作简便,可在高速公路设计的成果上直接转换得到能进行仿真的仿真路网。(The invention discloses a method for quickly establishing a Vissim simulation road network by using road data, which comprises the following steps: s1, loading an SDB project file of road design software, and analyzing the connection relation of the horizontal and vertical routes, the design speed, the cross section, the flow splitting area, the flow merging area, the horizontal intersection range and the linear position; s2, splitting the road section into a general road section and a special road section according to the road width condition, the dividing and merging flow and the level crossing; s3, road section conversion is carried out, wherein the road section conversion comprises two parts of lane structure analysis and lane data analysis, and the lane structure analysis refers to that the part condition in the road section is converted into a data structure formed by combining the road section according with Vissim and the connector; and S4, outputting the converted general road sections and special road sections into extensible markup language, and combining the extensible markup language with the template to generate a project file which can be directly used by the Vissim. The method is easy to implement and simple and convenient to operate, and a simulation road network capable of performing simulation can be obtained by directly converting the results of the highway design.)

1. A method for quickly establishing a Vissim simulation road network by using road data comprises the following steps:

s1), loading an SDB project file of road design software, and analyzing the connection relation of the horizontal and vertical routes, the design speed, the cross section, the diversion area, the confluence area, the horizontal intersection range and the linear position; the read data come from SDB project files used by a JSL-route expert system, and the used route data are the project files used by latitude roads or EICAD integrated interactive roads and interchange design software route design software and are converted into SDB project files used by a route expert in the route expert;

s2), according to the road width condition, dividing and merging flow and level crossing, dividing the road section into two categories of general road section and special road section, wherein the general road section is a road section which only contains one traffic flow on the same design line, and the special road section is a road section which contains a plurality of traffic flows such as a dividing and merging part and level crossing or two design line direct-connection parts of the road section which only contains one traffic flow but contains a plurality of design lines;

s3), performing road section conversion, including two parts of lane structure analysis and lane data analysis, wherein the lane structure analysis refers to the fact that the part condition in the road section is converted into a data structure which is combined with the Vissim road section and the connector, the lane data analysis refers to the fact that the design speed and the cross section information are read, the lane central line and the lane composition are analyzed, the road section and the connector are assigned, the road sections of different types are converted according to different conversion methods, for the general road section, the situation is further judged to contain the widening and is respectively analyzed and converted, for the special road section, the division part, the confluence part, the T-shaped intersection, the cross-shaped intersection and the direct connection are respectively considered, and for the division part and the confluence part, the situation of the auxiliary lane and the gradual change section is further judged; judging the number of lanes for T-shaped level crossing and cross-shaped level crossing and connecting according to rules; judging the number of lanes on two sides for the direct connection, and connecting the lanes on the inner side of the design line;

s4), outputting the converted general road section and special road section into extensible markup language, combining the template to generate item file which the Vissim can directly use, without using serial communication port interface of the Vissim, generating directly with the extensible markup language, except the information of lane composition and the information of lane coordinate set, according to the characteristics of the highway, assigning values according to the following table for other information:

2. the method for rapidly building Vissim simulation road network by using road data as claimed in claim 1, wherein: in the step (S2), the splitting of the road segment and the special road segment includes the following steps:

A. reading the design lines and the corresponding cross sections, judging whether one design line has paragraphs with different road widths, and if yes, splitting according to the paragraphs;

B. judging whether the split road section is two lanes or not, and further splitting the split road section into a left road section and a right road section if the split road section is two lanes;

C. judging whether the road sections contain branching and merging ports and intersection ports or not, if so, splitting the special road sections, and taking the rest parts as general road sections;

D. and searching linear position bearing relation, and incorporating the linear position bearing relation into the special road section for the direct connection relation.

3. The method for rapidly building Vissim simulation road network by using road data as claimed in claim 1, wherein: the step (S3) is performed by parsing and converting:

in the general road section, if the road section contains a widened paragraph, the road section is directly converted into a single Vissim road section if the road section does not contain the widened paragraph, a non-gradual change section is converted into two Vissim road sections, the gradual change section is connected through two connectors, one connector is connected with inner side lanes of the two Vissim road sections, the other connector is used for connecting an outermost lane of a designed line and a widened lane, after the composition of the Vissim road sections and the connectors is determined, parameters, a running lane coordinate point set and lane composition are determined, for the running lane composition of the road section, a design speed is read, a corresponding single lane width is inquired according to a standard, the running lane width is divided by the single lane width to be rounded as the number of lanes, the widening is indicated by a remainder, the lane widening is added to the outermost lane according to a design habit, for the lane widening is performed for the running lane center coordinate set of the road section, a deviation distance from the center of the running lane to the designed line is calculated firstly, and calculating a center coordinate set of the lanes according to a certain step length, calculating lane offset distances corresponding to the midpoints of the connectors respectively, and calculating the coordinate set according to linear gradual change.

4. The method for rapidly building Vissim simulation road network by using road data as claimed in claim 1, wherein: the splitting part in the step (S3) is composed of two connectors, one of the connectors is used for connecting a driving-in direction main line and a driving-out direction main line, the number of lanes is a smaller value of the number of lanes on two road sections, the number of lanes is connected from the inner side lane of the opposite design line, the other one is used for connecting the driving-out direction main line and the ramps, the number of lanes is the number of ramps, the number of lanes is connected from the outer side lane of the opposite design line, the central offset distance of the corresponding lane is calculated by the connectors of the driving-in direction main line and the driving-out direction main line, the center point set is calculated according to the step length, the connector center point set of the driving-in direction main line and the driving-out direction main line is determined to contain a gradual change section and an auxiliary lane, for the case that the gradual change section is not contained, the offset distance from the coordinates of the starting point of the connectors to the driving-out direction main line is calculated, and the coordinate set is calculated according to the step length line type; for the condition that the transition section is contained and the auxiliary lane is not contained, the distance from the starting point to the terminal point to the main line of the driving-in direction and the distance from the terminal point to the main line of the driving-out direction are respectively calculated by two sections of the transition section and the deceleration lane section, and the coordinate sets are respectively calculated according to the step linear gradual change; for the situation containing the transition section and the auxiliary lane, three sections of the transition section, the auxiliary lane section and the deceleration lane section are divided to calculate the distance from the starting point and the ending point to the main line of the driving-in direction and the main line of the driving-out direction, and the coordinate sets are respectively calculated according to the step linear transition.

5. The method for rapidly building Vissim simulation road network by using road data as claimed in claim 1, wherein: the merging portion in the step (S3) is also composed of two connectors, the connection of the driving-in direction main line and the driving-out direction main line is consistent with the branching portion, the composition of the ramp and the connector lane of the driving-in direction main line and the driving-out direction main line is also consistent with the branching portion, the determination of the set of the connector center points of the ramp and the driving-in direction main line and the driving-out direction main line contains a gradual change section and an auxiliary lane, for the case that the gradual change section is not contained, the offset distance from the coordinates of the starting and ending points of the connectors to the design line of the driving-in direction main line and the driving-out direction main line is calculated, and the coordinate set is calculated according to the step linear gradual change; for the condition that the gradient section does not contain an auxiliary lane, calculating the distance from the start point to the end point of a ramp design line, from the end point of the ramp design line to the end point of an acceleration lane and from the end point to a main line of the driving-in direction and a main line of the driving-out direction by three sections, and respectively calculating a coordinate set according to the linear gradient of the step length; for the condition containing the gradual change section and the auxiliary lane, the distance from the start point to the end point of the ramp design line to the end point of the acceleration lane, the distance from the end point to the main line of the driving-in direction and the distance from the end point to the main line of the driving-out direction are calculated according to four sections of the ramp design line, the ramp design line and the gradual change section, and the coordinate set is respectively calculated according to the step linear gradual change.

6. The method for rapidly building Vissim simulation road network by using road data as claimed in claim 1, wherein: the T-shaped intersections in the step (S3) are divided into 3 × 2 — 6 sets of connectors, for a single set of connectors, the number of lanes on two road segments to be connected is compared, the same set of connectors only includes one connector, the lanes directly correspond to the two road segments, for the case where the number of lanes on two road segments is different, the first connector is determined according to the number of lanes, the lane is connected from the inner side of the design line, the second connector is used for connecting the lane with the outer lane, for the coordinate point set, the tangent circular arc of the start and end point is calculated, the specific coordinates on the circular arc are calculated according to the step length to form a coordinate set, and the circular arc is replaced by a straight line if the radius is infinite.

7. The method for rapidly building Vissim simulation road network by using road data as claimed in claim 1, wherein: the cross-shaped crossroads in the step (S3) are divided into 4 × 3 — 12 sets of connectors, and the single-set connectors are aligned with the T-shaped crossroads.

Technical Field

The invention relates to the technical field of road traffic, in particular to a method for quickly establishing a Vissim simulation road network by using data commonly used on expressways.

Background

With the increase of the quantity of automobiles in China and the rapid increase of traffic volume, the phenomena of insufficient traffic capacity or reduced service level and the like appear in different degrees of the highway built at early stage, even traffic jam is caused, and reconstruction and expansion are needed to meet the traffic demand. On one hand, the traffic organization design is an important component of the highway reconstruction and extension design, and needs to be designed by comprehensively considering indexes such as saturation, travel time, delay, queuing length and the like of a road, and on the other hand, designers can visually observe the vehicle running state under the design scheme through simulation, and the improvement of the overall level of the highway reconstruction and extension design is facilitated.

The Vissim as a micro simulation software has the functions of simulating and outputting the indexes. However, the establishment of the Vissim road network requires the superposition of design base maps to be established in a point-by-point manner, which not only has low efficiency, but also affects the authenticity of simulation results due to limited precision.

At present, road design basically uses road design software, and the design using the road design software keeps digitized design results. Therefore, a method for quickly establishing a Vissim simulation road network by using basic data of an expressway is provided by a digital method, and the method becomes a problem to be solved by researchers in the field.

Disclosure of Invention

The invention aims to provide a method for quickly establishing a Vissim simulation road network by using common data of expressways, which is easy and convenient to operate and can directly convert results of expressways design to obtain a simulation road network capable of simulating.

In order to achieve the purpose, the invention adopts the following technical measures:

a method for quickly establishing a Vissim simulation road network by using road data comprises the following steps:

s1, loading an SDB project file of road design software, and analyzing the connection relation of the horizontal and vertical routes, the design speed, the cross section, the flow splitting area, the flow merging area, the horizontal intersection range and the linear position; the read data comes from an SDB project file used by a JSL-route expert system, and if the used route data is a project file used by other route design software such as latitude road or EICAD integrated interactive road and interchange design software, the data can be converted into an SDB project file used by a route expert in the route expert, and the software is as follows: the JSL-route expert system is composed of a route produced by China Mobile second Highway research and design research institute limited company and interchange CAD design software (existing software).

And S2, dividing the road section into a general road section and a special road section according to the road width condition, the dividing and merging flow and the level crossing, wherein the general road section only contains one traffic flow on the same design line, and the special road section only contains a plurality of traffic flows such as a dividing and merging portion and the level crossing or a road section only contains one traffic flow but contains a plurality of design lines such as two design line direct-connection portions. The splitting result is shown in fig. 2 by taking an example of ground intercommunication of a single horn, wherein the gray part is a general road section and the yellow part is a special road section. And finally, storing the connection relation between the general road section and the special road section, and additionally reading the linear position bearing relation to be taken into consideration of the special road section as sequential connection.

And S3, performing road section analysis and conversion, wherein the road section analysis comprises two parts of a traffic lane structure analysis and a traffic lane data analysis, and the traffic lane structure analysis refers to that the part condition in the road section is converted into a data structure formed by combining the road section according with the Vissim and the connector. The lane data analysis means reading information such as design speed, cross section and the like, analyzing lane central lines and lane components, and assigning values to road sections and connectors. Meanwhile, different types of road sections need to be converted according to different conversion methods. For a general link, it is necessary to further determine whether or not there is a broadening and perform analysis conversion separately. For special road sections, the branch flow part, the confluence part, the T-shaped level crossing, the cross level crossing and the direct connection are respectively considered. For the diversion part and the confluence part, the conditions of an auxiliary lane and a gradual change section need to be further judged; judging the number of lanes required for T-shaped level crossing and cross-shaped level crossing and connecting according to rules; and judging the number of lanes on two sides for the direct connection, and connecting the lanes on the inner side of the design line.

And S4, outputting the converted general road sections and the converted special road sections into extensible markup language (XML), and combining the XML with a template to generate a project file which can be directly used by the Vissim. In this step, a serial communication port (COM) interface of Vissim is not used, but is directly generated in an extensible markup language (XML) form, and other information except information of lane composition and lane coordinate set information is assigned according to the following table according to the characteristics of the highway:

in addition, the designed speed attribute value is a route designed speed, the serial number attribute is divided into a road section and a connector, the road section is sequentially assigned according to the generation sequence from 0, and the connector is sequentially assigned according to the generation sequence from 10000.

The step S2 is splitting a road segment and a special road segment, where the splitting includes the following steps:

A. reading the design line and the corresponding cross section, judging whether a section with different road widths exists in one design line, and if so, splitting according to the section.

B. And judging whether the split road section is two lanes or not, and further splitting the road section into a left road section and a right road section if the split road section is two lanes.

C. And judging whether the road sections contain branching and converging flows and level intersections, splitting special road sections if the road sections contain the branching and converging flows and level intersections, and taking the rest parts as common road sections.

D. And searching the linear position connection relation, and taking the directly connected gradual change road sections as the direct connection relation to be incorporated into the special road sections.

The case-by-case parsing and conversion in step S3 is performed as follows:

the general road section in step S3 needs to determine whether there is a widening section, if not, the general road section is directly converted into a single Vissim road section, if so, the non-widening section is converted into two Vissim road sections, in the tapering section, the two connectors are used for connection, one connector connects the inner lanes of the two Vissim road sections, and the other connector is used for connecting the outermost lane of the design line and the widening lane. After the Vissim road section and the connector are determined to be formed, specific parameters are required to be determined, and two aspects of a traffic lane coordinate point set and a traffic lane composition are mainly included. For the composition of the lanes of the road section, the design speed needs to be read, the corresponding single lane width is inquired according to the standard, the lane width is divided by the single lane width to be rounded to be used as the number of lanes, if the remainder indicates that the widening condition exists, the widening condition is added to the outermost lane of the design line according to the design habit to be used as lane widening. For the center coordinate set of the traffic lane of the road section, the offset distance from the center of the traffic lane to the design line can be calculated firstly, and then the center coordinate set of the traffic lane can be calculated according to a certain step length. For the connector, the lane offset distances corresponding to the middle points of the connector are calculated, and the coordinate set is calculated according to linear gradient

The splitting unit in step S3 is composed of two connectors, one of which is used to connect the driving-in direction main line and the driving-out direction main line, the number of lanes is the smaller of the number of lanes on two road sections, and is connected from the inner side of the design line, the other is used to connect the driving-in direction main line and the ramp, the number of lanes is the number of ramps, and is connected from the outer side of the design line. The connectors of the driving-in direction main line and the driving-out direction main line need to calculate the center offset distance of the corresponding lane, and a center point set is calculated according to the step length. Determining the central point set of the connector of the main line and the ramp in the driving-in direction, considering whether a transition section and an auxiliary lane are contained, calculating the offset distance from the coordinate of the starting point and the ending point of the connector to the design line of the main line in the driving-out direction under the condition that the transition section is not contained, and calculating the coordinate set according to the step linear transition; for the situation that the transition section is contained and the auxiliary lane is not contained, the distance from the starting point to the terminal point to the main line of the driving-in direction and the distance from the terminal point to the main line of the driving-out direction need to be calculated respectively by two sections of the transition section and the deceleration lane section, and the coordinate sets are calculated respectively according to the step linear gradual change; for the situation containing the transition section and the auxiliary lane, three sections of the transition section, the auxiliary lane section and the deceleration lane section are required to be divided to calculate the distance from the starting point and the ending point to the main line of the driving-in direction and the main line of the driving-out direction, and the coordinate sets are respectively calculated according to the step linear transition.

The merging portion in step S3 is also composed of two connectors, and the connection between the main line of the entering direction and the main line of the exiting direction is consistent with the branching portion, which is not described again, and the composition of the ramp and the connector lanes of the main line of the entering direction and the main line of the exiting direction is also consistent with the branching portion. The determination of the ramp and the set of connector center points of the main line of the entering direction and the main line of the exiting direction also needs to consider whether the ramp section and the auxiliary lane are included. For the condition that the connector does not contain the transition section, calculating the offset distance from the coordinates of the starting point and the ending point of the connector to the design line of the main line of the driving-in direction and the main line of the driving-out direction, and calculating a coordinate set according to the step linear transition; for the condition that the gradient section does not contain an auxiliary lane, the distance from the start point to the end point of a ramp design line, the distance from the end point to the main line of the driving-in direction and the distance from the end point to the main line of the driving-out direction need to be calculated by three sections, and the coordinate set is respectively calculated according to the linear gradient of the step length; for the condition containing the gradual change section and the auxiliary lane, the distance from the start point to the end point of the ramp design line to the end point of the acceleration lane, the distance from the end point to the main line of the driving-in direction and the distance from the end point to the main line of the driving-out direction are calculated according to the step linear gradual change.

The T-shaped intersection in step S3 needs to be divided into 3 × 2 — 6 sets of connectors, and for a single set of connectors, the number of lanes on two road segments to be connected needs to be compared, and if the number of lanes on the two road segments is the same, the set of connectors only includes one connector, and the lanes directly correspond to the two road segments. And determining a first connector according to the lanes with less number for the condition that the number of lanes on the two road sections is different, and connecting the lanes on the inner side of the design line. The second connector is used for connecting the extra lane with the external lane. For the coordinate point set, a tangent circular arc of a starting point and a finishing point needs to be calculated, specific coordinates on the circular arc are calculated according to step length to form the coordinate set, and if the radius obtained by calculation is infinite, the circular arc is replaced by a straight line.

The cross-shaped intersection in step S3 needs to be divided into 4 × 3 — 12 sets of connectors, and the single-set connectors are consistent with the T-shaped intersection.

Typically 1/12 at the design speed.

The present invention will be described with respect to design lines, cross sections, general sections, special sections, Vissim connectors (terms related to the present application), and the like as follows:

designing a line: the three-dimensional shape of the central line of the road width consists of a plane design line and a vertical section design line.

The cross section is as follows: the normal section of any point on the midline comprises a traffic lane, a road shoulder, a division strip, a side ditch, a side slope, a catch basin, a protective ramp way, a soil pit, a waste soil pile, an environment protection facility and the like.

General road section: and on the same design line, only one road section of the traffic flow is included at the same time.

The special road section: road sections containing multiple traffic flows such as a dividing and merging part and a level crossing or only containing one traffic flow but containing multiple design lines such as two design line direct-connection parts.

And (4) Vissim road section: the basic unit of the Vissim road network comprises at least 1 equal-width lane with the width larger than 0;

vissim connector: and the basic unit of the Vissim road network is used for connecting the lanes in the two Vissim road sections, comprises the serial numbers of the lanes in the Vissim road sections corresponding to the starting and ending points, and the number of the lanes at the starting and ending points must be consistent.

It should be noted that the detailed description in this embodiment is exemplary and is intended to provide further explanation of the present application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

The most critical are the two steps of S2 and S3. The expressway is split, corresponding relations are established one by one according to the split objects according to the type and the condition, and conversion is carried out. The invention ensures that designers can quickly and accurately obtain the road network model for traffic simulation by directly utilizing design results. Compared with the prior art that the simulation road network model is established in a manual scanning mode, the efficiency is greatly improved, the accuracy of the road network model is improved, and the authenticity of simulation is guaranteed. In addition, because the road network model is output by directly outputting the XML, the conversion can be carried out on equipment without installing simulation software.

In order to ensure the normal implementation of the invention, an example program is written according to the steps and a certain floor intercommunication, a certain U-turn lane and a certain junction intercommunication are respectively selected for experimental verification, the program logic of the verification program interface is consistent with that described in the foregoing, and by respectively importing test item files, it needs to be explained that the engineering coordinate system adopts six to eight coordinates, which is not beneficial to directly operating in simulation software, so that a certain offset value is recommended to be input to ensure that the generated road network is positioned near the origin of coordinates, thereby facilitating the subsequent work. Clicking the export road network results in the XML file shown in fig. 4. The final result is shown in fig. 5, 6 and 7, the upper half is the design drawing, and the lower half is the road network after conversion, as can be seen from fig. 5, 6 and 7, the three tested expressways are all converted into the corresponding simulated road network well, and the required time is within 5 seconds.

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

for the design of the expressway conforming to the industrial standard, the manual workload required for obtaining the Vissim road network is very small, particularly, the design by using the JSL-route expert system only needs to import the corresponding project file, a great deal of manpower is saved, the method is easy to implement, the operation is simple and convenient, the simulated road network capable of being simulated can be obtained by directly converting the result of the expressway design, the speed of generating the road network is very high, and even for a large hub, the second-level road network can be ensured. The method is independent of simulation software, and can also perform road network generation operation even on equipment without the authorization of the simulation software.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a flow chart of a method for quickly establishing a Vissim simulation road network by using road data.

Fig. 2 is a schematic road segment splitting diagram of a method for quickly establishing a Vissim simulation road network by using road data.

Fig. 3 is a schematic view of a verification program interface of a method for quickly establishing a Vissim simulation road network by using road data.

Fig. 4 is a schematic diagram of an XML structure available for Vissim output by a method for quickly establishing a Vissim simulation road network by using data commonly used in expressways.

Fig. 5 is a schematic view of the floor intercommunication of a certain single horn generated by the test of the method for quickly establishing the Vissim simulation road network by using the road data.

The upper half of the graph is a general graph of the design, and the lower half of the graph is a Vissim road network after generation.

Fig. 6 is a schematic diagram of a turn-around lane generated by a test of a method for quickly establishing a Vissim simulation road network by using road data.

The upper half of the graph is a general graph of the design, and the lower half of the graph is a Vissim road network after generation.

Fig. 7 is a schematic view of hub intercommunication generated by a test of a method for quickly establishing a Vissim simulation road network by using road data.

The upper half of the graph is a general graph of the design, and the lower half of the graph is a Vissim road network after generation.

Detailed Description

Example 1:

the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1, fig. 2, fig. 3, fig. 4, fig. 5, fig. 6, and fig. 7, a method for quickly establishing a Vissim simulation road network by using data commonly used for highways includes the following steps:

loading an SDB project file of road design software, and analyzing the connection relation of the horizontal and vertical lines, the design speed, the cross section, the shunting area, the confluence area, the horizontal intersection range and the line position. The read data come from SDB files used by JSL-routes, and if the used route data are project files used by other route design software such as latitude and EICAD, the data can be converted into SDB files in the route experts, and the software is as follows: the JSL-route expert system is provided with the route and interchange CAD design software which are delivered by the second highway investigation and design research institute company Limited.

Reading the design lines and the corresponding cross sections, judging whether one design line has paragraphs with different road widths, and if yes, splitting according to the paragraphs. And judging whether the split road section is two lanes or not, and further splitting the road section into a left road section and a right road section if the split road section is two lanes. And judging whether the road sections contain branching and converging flows and level intersections, splitting special road sections if the road sections contain the branching and converging flows and level intersections, and taking the rest parts as common road sections.

Thirdly, analyzing and converting road sections, including two parts of lane structure analysis and lane data analysis, under the following conditions:

in the general road section, whether a widened section exists needs to be judged, if not, the widened section is directly converted into a single Vissim section, if so, a non-gradual-change section is converted into two Vissim sections, in the gradual-change section, the gradual-change section is connected through two connectors, one connector is connected with inner lanes of the two Vissim sections, and the other connector is used for connecting the outermost lane of the design line and the widened lane. After the Vissim road section and the connector are determined to be formed, specific parameters are required to be determined, and two aspects of a traffic lane coordinate point set and a traffic lane composition are mainly included. For the composition of the lanes of the road section, the design speed needs to be read, the corresponding single lane width is inquired according to the standard, the lane width is divided by the single lane width to be rounded to be used as the number of lanes, if the remainder indicates that the widening condition exists, the widening condition is added to the outermost lane of the design line according to the design habit to be used as lane widening. For the center coordinate set of the traffic lane of the road section, the offset distance from the center of the traffic lane to the design line can be calculated firstly, and then the center coordinate set of the traffic lane can be calculated according to a certain step length. For the connector, it is necessary to calculate lane offsets corresponding to the midpoints thereof, and calculate a coordinate set according to linear gradients.

And the shunting part in the third step consists of two connectors, wherein one connector is used for connecting the main line and the main line, the number of the lanes is the smaller value of the number of the lanes on the two road sections, the number of the lanes is connected from the inner side of the design line, the other connector is used for connecting the main line and the ramp, the number of the lanes is the number of the ramps, and the lanes are connected from the outer side of the design line. The connectors of the driving-in direction main line and the driving-out direction main line need to calculate the center offset distance of the corresponding lane, and a center point set is calculated according to the step length. Determining the connector central point set of the main line of the driving-in direction, the main line of the driving-out direction and the ramp, considering whether a transition section and an auxiliary lane are included, calculating the offset distance from the coordinates of the starting point and the ending point of the connector to the design line of the main line of the driving-in direction and the main line of the driving-out direction for the condition that the transition section is not included, and calculating the coordinate set according to the step linear transition; for the situation that the transition section is contained and the auxiliary lane is not contained, the distance from the starting point to the terminal point to the main line of the driving-in direction and the distance from the terminal point to the main line of the driving-out direction need to be calculated respectively by two sections of the transition section and the deceleration lane section, and the coordinate sets are calculated respectively according to the step linear gradual change; for the situation containing the transition section and the auxiliary lane, three sections of the transition section, the auxiliary lane section and the deceleration lane section are required to be divided to calculate the distance from the starting point and the ending point to the main line of the driving-in direction and the main line of the driving-out direction, and the coordinate sets are respectively calculated according to the step linear transition.

The merging section in the third step is also composed of two connectors, the connection of the main line in the driving-in direction and the main line in the driving-out direction is consistent with the branching section, and the composition of the ramp and the connector lanes of the main line in the driving-in direction and the main line in the driving-out direction is also consistent with the branching section. The determination of the ramp and the set of connector center points of the main line of the entering direction and the main line of the exiting direction also needs to consider whether the ramp section and the auxiliary lane are included. For the condition that the connector does not contain the transition section, calculating the offset distance from the coordinates of the starting point and the ending point of the connector to the design line of the main line of the driving-in direction and the main line of the driving-out direction, and calculating a coordinate set according to the step linear transition; for the condition that the gradient section does not contain an auxiliary lane, the distance from the start point to the end point of a ramp design line, the distance from the end point to the main line of the driving-in direction and the distance from the end point to the main line of the driving-out direction need to be calculated by three sections, and the coordinate set is respectively calculated according to the linear gradient of the step length; for the condition containing the gradual change section and the auxiliary lane, the distance from the start point to the end point of the ramp design line to the end point of the acceleration lane, the distance from the end point to the main line of the driving-in direction and the distance from the end point to the main line of the driving-out direction are calculated according to the step linear gradual change.

The T-shaped intersection in step three needs to be divided into 3 × 2 — 6 sets of connectors, for a single set of connectors, the number of lanes on two connected road segments needs to be compared, if the connectors are the same, the set of connectors only contains one connector, and the lane directly corresponds to the two road segments. And determining the first connector according to the lanes with less number for the condition that the number of lanes on the two road sections is different, and connecting from the inner lanes. The second connector is used for connecting the extra lane with the external lane. For the coordinate point set, a tangent circular arc of a starting point and a finishing point needs to be calculated, specific coordinates on the circular arc are calculated according to step length to form the coordinate set, and if the radius obtained by calculation is infinite, the circular arc is replaced by a straight line.

The cross-shaped level crossing in the third step needs to be divided into 12 groups of connectors, namely 4 × 3 groups of connectors, and for a single group of connectors, the cross-shaped level crossing is consistent with the T-shaped level crossing.

Outputting the converted general road sections and the converted special road sections in an extensible markup language (XML) form, and generating a project file which can be directly used by the Vissim by combining a template. In this step, a serial communication port (COM interface) of Vissim is not used, but is directly generated in an extensible markup language (XML) form, and other information except information of lane composition and information of a lane coordinate set is assigned according to the following table according to the characteristics of the highway:

according to specific conditions, part of parameters in the table can also be other numerical values.

In addition, the designed speed attribute value is a route designed speed, the serial number attribute is divided into a road section and a connector, the road section is sequentially assigned according to the generation sequence from 0, and the connector is sequentially assigned according to the generation sequence from 10000.

By the specific technical measures, the road network for Vissim traffic simulation is obtained quickly and accurately.