Elastic traffic control method considering road accumulated water distribution

Abstract

The invention provides an elastic traffic control method considering road accumulated water distribution. The method comprises the steps of collecting road surface point cloud data and obtaining a road three-dimensional model; utilizing computational fluid mechanics simulation software to construct a road ponding simulation model under the rainfall condition; according to the simulation result, calculating the critical water skiing speed corresponding to the accumulated water depth, and comparing the critical water skiing speed with the lane speed limit to judge the water skiing risk; the sections with the water skiing risk are divided into risk sections; reducing the maximum limit driving speed of the risk section; dividing a high-risk section by comparing the maximum speed limit with a preset threshold value, and performing bypassing adjustment; by comparing the proportion of the risk section with a preset safety threshold value, a channel sealing measure is taken; and real-time weather and road conditions are continuously monitored and timely adjusted. By means of the method, the lane speed limit and the traffic flow direction are dynamically adjusted, tackle and traffic accidents caused by accumulated water on the road surface are effectively prevented, the water skiing risk of vehicles under the rainfall condition is reduced, and the road traffic safety is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of traffic control, and in particular to a flexible traffic control method that takes into account the distribution of road water accumulation, aiming to reduce the risk of vehicle hydroplaning under rainfall conditions and ensure road traffic safety by dynamically adjusting lane speed limits and closure measures. Background Art

[0002] In modern urban traffic systems, the impact of rainy weather on road traffic safety is very significant, especially in heavy rain conditions, where road waterlogging becomes more prominent. Road waterlogging not only reduces the friction coefficient of the road and increases the risk of vehicle skidding, but can also lead to vehicle loss of control and traffic accidents. Therefore, effective road waterlogging monitoring and traffic control measures are essential to ensure driving safety.

[0003] In the prior art, some traffic management departments usually only focus on the water accumulation problem in the underpass area when dealing with heavy rainfall. This is because the underpass area is more prone to water accumulation due to its low-lying terrain, posing a direct threat to traffic safety. However, studies have shown that heavy rainfall not only causes water accumulation in low-lying areas, but also forms a layer of water film on the road surface. Although this layer of water film is not as easy to detect as obvious water accumulation, it will also significantly reduce the friction coefficient between the tire and the road surface, increase the risk of hydroplaning of high-speed vehicles, and thus increase the probability of traffic accidents.

[0004] On the other hand, existing traffic control measures are usually mainly aimed at vehicle control measures in situations such as traffic accidents, traffic congestion and fog. For example, the traffic management system will promptly adjust traffic signals and guide vehicles to detour when a traffic accident occurs, and will use dynamic speed limits and lane control to ease traffic in traffic congestion. In foggy weather, the vehicle speed limit will be adjusted according to visibility. However, these control measures often fail to fully consider the impact of road water film on driving safety in heavy rainfall weather, and lack dynamic traffic control strategies for rainfall intensity and road hydroplaning risks. Summary of the invention

[0005] The purpose of the present invention is to provide a traffic control method that takes into account the impact of road water film on driving safety during heavy rainfall weather, with respect to rainfall intensity and road hydroplaning risk.

[0006] To achieve the above object, the present invention proposes a flexible traffic control method considering road waterlogging distribution, comprising the following steps:

[0007] S1: Collect continuous point cloud data of the road surface and obtain a three-dimensional model of the road;

[0008] S2: Based on the three-dimensional road model, a road waterlogging simulation model under rainfall conditions is constructed using computational fluid dynamics simulation software to simulate the distribution of road waterlogging under different rainfall intensities;

[0009] S3: Calculate the critical hydroplaning speed corresponding to the water depth based on the simulation results, and compare it with the lane speed limit to determine the hydroplaning risk;

[0010] S4: Divide the sections along the lane direction and mark the sections with hydroplaning risk as risk sections;

[0011] S5: Reduce the maximum speed limit in the risk section, impose speed reduction requirements, and form a speed reduction buffer zone;

[0012] S6: When the speed limit of the risk section is reduced to a preset threshold and still cannot guarantee safety, the risk section is marked as a high-risk section, and a detour protocol is triggered to perform detour adjustment;

[0013] S7: When the proportion of high-risk sections on the lane exceeds the preset safety threshold, road closure measures are implemented;

[0014] S8: Continuously monitor real-time weather and road condition data in high-risk areas on the lanes and make timely adjustments.

[0015] Furthermore, step S1 is specifically as follows:

[0016] S1.1: Use a laser point cloud acquisition device to collect continuous point cloud data of the road surface, wherein the point cloud data includes three-dimensional coordinate information and reflection intensity information;

[0017] S1.2: Using a point cloud reconstruction algorithm, the point cloud data is processed to obtain a three-dimensional road model, thereby reconstructing the three-dimensional road surface model.

[0018] Furthermore, the laser point cloud acquisition device needs to adjust the installation position to ensure sampling accuracy and sampling density.

[0019] Furthermore, the laser point cloud acquisition device is a laser radar scanning device.

[0020] Furthermore, in step S2, the method for constructing the road waterlogging simulation model is specifically as follows:

[0021] S2.1: Create geometric model - Use CAD software to use the reconstructed 3D road surface model as the bottom surface of the fluid model, and select the range 1m above the bottom surface as the calculation area to create a solid model of the fluid domain;

[0022] S2.2: Meshing - Use the meshing function in the computational fluid dynamics software to mesh the geometric model;

[0023] S2.3: Model solving - Import the grid file into the computational fluid dynamics solver, complete the boundary conditions and model settings, and then solve it.

[0024] Furthermore, the road waterlogging simulation model includes rainfall simulation, road surface runoff simulation and road surface seepage simulation.

[0025] Furthermore, in step S3, the specific method for determining the risk of hydroplaning is as follows: based on the simulation results, the critical hydroplaning speed corresponding to the water depth is calculated; the critical hydroplaning speed corresponding to the maximum water depth in the lane is compared with the lane speed limit; if the lane speed limit exceeds the critical hydroplaning speed corresponding to the water depth in the lane, it is considered that there is a risk of hydroplaning when driving at the lane speed limit in the lane.

[0026] Furthermore, in step S4, the specific method of dividing the risk sections is:

[0027] S4.1: Associating the simulation data based on the three-dimensional road model with the precise geographic location, and dividing each unit section at a certain interval along the lane direction;

[0028] S4.2: Based on meteorological information, the road surface waterlogging situation during rainfall is simulated and calculated in real time, and the result is solved based on the hydroplaning speed at the maximum water depth in the unit section. If there is a hydroplaning risk in a unit section, the section is automatically marked as a risk section.

[0029] Furthermore, step S5 is specifically as follows: lowering the maximum speed limit of the marked risk section, and imposing a speed reduction requirement on the risk section and its preceding adjacent section according to the risk level, sending a deceleration instruction to vehicles traveling on the lane and not reaching the buffer zone, and setting a temporary speed limit sign in the relevant area through an integrated traffic control system; forming a speed reduction buffer zone to ensure that the vehicle can smoothly transition to the adjusted speed when entering or leaving the risk section.

[0030] Furthermore, in step S6, the specific method of detour adjustment is: when the speed limit of the risk section of a lane is adjusted to a preset threshold and safety cannot be guaranteed, the section is marked as a high-risk section and the detour protocol is triggered; before reaching the speed reduction buffer zone, a detour instruction is sent to the vehicle traveling on the lane, and the traffic control system will automatically adjust the signal light cycle and green light time of the surrounding road network according to the detour requirements, optimize the traffic flow of the detour route, and reduce the impact of the detour on the overall traffic flow.

[0031] Furthermore, in step S7, the road closure measures are specifically as follows: when the proportion of high-risk sections in a lane exceeds a preset safety threshold, a closure instruction is sent through the traffic control system, and road closure facilities (such as electronic information boards and variable signs) are activated to close the lane; at the same time, the traffic control system guides vehicles through the information release system and traffic signal adjustments, and diverts them to other lanes or recommended detours.

[0032] Furthermore, step S8 is specifically as follows: when speed limit adjustment or road closure is adopted, real-time weather and road condition data of the area are continuously monitored; once the conditions of the risky road section are improved and the critical hydroplaning speed rises back to a safe range, the speed limit or detour instruction is promptly revoked, the public and vehicles are notified through various communication channels, and the detour route is adjusted to optimize the traffic flow of the entire road network.

[0033] The method of the invention obtains a three-dimensional model of a road surface by using a vehicle-mounted laser point cloud technology, and obtains the distribution characteristics of road surface water under different rainfall intensities by using a simulation or numerical calculation method.

[0034] Furthermore, the present invention calculates the hydroplaning risk of vehicles at different speeds through a vehicle simulation model, and in particular, finely manages the hydroplaning risk of different lanes and vehicle types. According to the calculation results, the lane speed limit is dynamically adjusted, and closure measures are implemented when necessary to ensure that the risk of hydroplaning can be effectively reduced in heavy rain weather and ensure the safety and smoothness of road traffic.

[0035] Compared with the prior art, the advantages of the present invention are:

[0036] 1. The present invention obtains the three-dimensional morphology of the road surface through laser point cloud information, and simulates the water accumulation condition of the road surface under rainy weather conditions using computational fluid dynamics simulation software, and obtains the water accumulation conditions at various locations on the road surface in real time, which is used as a data basis to judge the risk of hydroplaning on the road surface, thereby dynamically adjusting the lane speed limit and traffic flow direction and closure measures, effectively preventing skidding and traffic accidents caused by road water accumulation, reducing the risk of hydroplaning of vehicles under rainy conditions, and ensuring road traffic safety.

[0037] 2. The present invention comprehensively considers the impact of road water film and vehicle type on the risk of hydroplaning, and the proposed control method is highly automated and intelligent, which not only enhances the flexibility and adaptability of urban traffic control, but also provides effective technical support for urban traffic control under extreme weather conditions, filling the gap in existing technologies in driving safety management under heavy rainfall. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of a flow chart of a flexible traffic control method considering road waterlogging distribution according to an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of a road surface of a reconstructed three-dimensional road surface model in an embodiment of the present invention;

[0040] Figure 3 Schematic diagram of road surface water depth simulation results of a road water accumulation simulation model in an embodiment of the present invention;

[0041] Figure 4Schematic diagram of water flow velocity simulation results of the road waterlogging simulation model in an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be further described below.

[0043] This embodiment of the present invention proposes a flexible traffic control method that takes into account the distribution of road water accumulation. The method mainly uses laser point cloud information to obtain the three-dimensional shape of the road surface, and uses computational fluid dynamics simulation software to simulate the water accumulation condition of the road surface under rainy weather conditions, and obtains the water accumulation condition of each part of the road surface in real time. It serves as a data basis for judging the risk of hydroplaning on the road surface, thereby dynamically adjusting the lane speed limit and traffic flow, and effectively preventing hydroplaning and traffic accidents caused by road water accumulation. Figure 1 As shown, the method comprises the following steps:

[0044] Step 1: Install laser point cloud acquisition equipment, collect continuous point cloud data of the road surface, and obtain the three-dimensional model of the road:

[0045] 1.1) Use laser point cloud acquisition equipment to collect continuous point cloud data of the road surface; in this embodiment, the vehicle-mounted laser radar equipment is installed behind the roof of the vehicle, and the lens shoots vertically downward to collect point cloud data including three-dimensional coordinate information and reflection intensity.

[0046] 1.2) Use the point cloud reconstruction algorithm to process the point cloud data, obtain the three-dimensional model of the road, and realize the reconstruction of the three-dimensional model of the road surface; in this embodiment, the point cloud reconstruction is performed using the triangulation method, specifically: the xy plane projection of the spatial point is triangulated, and the plane equations of the corresponding triangles in space are established, and the point method is used to calculate the value of z for the interpolation point.

[0047] In this embodiment, the reconstructed lane is the middle lane, the road section length is 1000m, and the reconstructed road surface is as follows: Figure 2 shown.

[0048] Step 2: Based on the three-dimensional road model, a simulation model of road waterlogging under rainfall conditions is constructed using computational fluid dynamics simulation software to simulate the distribution of road waterlogging under different rainfall intensities;

[0049] 2.1) Create a geometric model - Use CAD software to use the reconstructed 3D road surface model as the bottom surface of the fluid model, and select the range 1m above the bottom surface as the calculation area to create a solid model of the fluid domain;

[0050] 2.2) Meshing - Use the meshing function in the computational fluid dynamics software to mesh the geometric model;

[0051] 2.3) Model solving - Import the grid file into the computational fluid dynamics solver, complete the boundary conditions and model settings, and then solve it.

[0052] In this embodiment, Ansys Fluent software is used to simulate water accumulation. The simulation results are as follows: Figure 3 and Figure 4 As shown, when the rainfall intensity is 3mm / min, the maximum water depth recorded is 7.163mm and the maximum flow rate is 0.41m / s.

[0053] Step 3: Identify the risk of hydroplaning based on the simulation results;

[0054] 3.1) According to the depth of water accumulation, the critical water-skiing speed at which water-skiing occurs is calculated using the following formula:

[0055] a. When the water depth is less than 2.4 mm, the vehicle hydroplaning speed is:

[0056] v p =96.3d -0.259

[0057] b. When the water depth is greater than 2.4 mm, the vehicle hydroplaning speed is:

[0058] v p =4.94A

[0059] Among them, A is and d is the depth of water accumulation.

[0060] Therefore, when the water depth is 7.163 mm, the critical hydroplaning speed is 72.81 km / h.

[0061] 3.2) Compare the critical hydroplaning speed corresponding to the depth of water in the lane with the lane speed limit: If the lane speed limit exceeds the critical hydroplaning speed corresponding to the depth of water in the lane, it is considered that there is a risk of hydroplaning when driving at the lane speed limit in the lane.

[0062] Step 4: Divide the sections along the lane direction and divide the risk sections;

[0063] 4.1) Associating the simulation data based on the road 3D model with the precise geographic location, dividing each unit section at a spacing of 50m along the lane direction. In this embodiment, a total of 20 sections are divided;

[0064] 4.2) Based on meteorological information, the road surface waterlogging situation during rainfall is simulated and calculated in real time, and the hydroplaning speed at the maximum water depth in the unit section is solved. If there is a hydroplaning risk in a unit section, the section is automatically marked as a risk section; the lane speed limit in this embodiment is set to [90, 110] km / h. According to the waterlogging situation, a total of 7 sections are marked as risk sections.

[0065] Step 5: Speed ​​limit adjustment;

[0066] Specifically: lower the maximum speed limit in the marked risk section, impose speed reduction requirements on the risk section and its previous adjacent section according to the risk level, send deceleration instructions to vehicles traveling on the lane and not reaching the buffer zone, and set temporary speed limit signs in relevant areas through the integrated traffic control system; form a speed reduction buffer zone to ensure that vehicles can smoothly transition to the adjusted speed when entering or leaving the risk section.

[0067] In this embodiment, a speed reduction requirement is imposed on the risk section and the section within 50m before and after it, and the maximum driving speed is reduced to 70m / s. A deceleration instruction is sent to vehicles traveling in this lane that have not reached the buffer zone through LED display boards and traffic management apps along the road.

[0068] In addition, in step 5, if the speed limit of the risk section is reduced to the preset threshold and still cannot guarantee safety, the risk section is marked as a high-risk section, and the detour protocol is triggered to make detour adjustments; the specific method of detour adjustment is: before reaching the speed reduction buffer zone, a detour instruction is sent to the vehicles traveling on the lane, and the traffic control system will automatically adjust the signal light cycle and green light time of the surrounding road network according to the detour demand, optimize the traffic flow of the detour route, and reduce the impact of the detour on the overall traffic flow. If the proportion of high-risk sections on the lane exceeds the preset safety threshold, road closure measures are implemented. The specific road closure measures are: sending a closure instruction through the traffic control system, activating road closure facilities (such as electronic information boards and variable signs), and closing the lane; at the same time, the traffic control system guides vehicles through the information release system and traffic signal adjustment, and diverts them to other lanes or recommended detour routes.

[0069] Step 6: Continuously monitor the real-time weather and road condition data in the area. When the rainfall intensity weakens and the maximum water depth drops to a safe range, lift the speed limit adjustment, that is, cancel the speed limit or detour instructions, notify the public and vehicles through various communication channels, and adjust the detour route to optimize the traffic flow of the entire road network.

[0070] The method of the present invention obtains a three-dimensional model of a road surface through vehicle-mounted laser point cloud technology, and obtains the distribution characteristics of road surface water under different rainfall intensities by using simulation or numerical calculation methods; calculates the hydroplaning risk of vehicles at different speeds through a vehicle simulation model, and especially performs refined management of the hydroplaning risk of different lanes and vehicle types; dynamically adjusts the lane speed limit according to the calculation results, and implements closure measures when necessary, so as to ensure that the risk of hydroplaning can be effectively reduced in heavy rainfall weather and ensure the safety and smoothness of road traffic.

[0071] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any technician in the relevant technical field, without departing from the scope of the technical solution of the present invention, makes any form of equivalent replacement or modification to the technical solution and technical content disclosed in the present invention, which does not depart from the content of the technical solution of the present invention and still falls within the protection scope of the present invention.

Claims

1. A flexible traffic control method considering road waterlogging distribution, characterized in that: The steps include: S1: Collect continuous point cloud data of the road surface and obtain a three-dimensional model of the road; S2: Based on the three-dimensional road model, a road waterlogging simulation model under rainfall conditions is constructed using computational fluid dynamics simulation software to simulate the distribution of road waterlogging under different rainfall intensities; S3: Calculate the critical hydroplaning speed corresponding to the water depth based on the simulation results, and compare it with the lane speed limit to determine the risk of hydroplaning; S4: Divide the lanes into sections and mark the sections with hydroplaning risk as risky sections; S5: Reduce the maximum speed limit in the risk section, impose a speed reduction requirement, and mark the front adjacent section as a speed reduction buffer zone; S6: When the speed limit of the risk section is reduced to a preset threshold and safety cannot be guaranteed, the risk section is marked as a high-risk section, and a detour protocol is triggered to perform detour adjustment; S7: When the proportion of high-risk sections on the lane exceeds the preset safety threshold, road closure measures are implemented; S8: Continuously monitor real-time weather and road condition data in high-risk areas on the lanes and make timely adjustments.

2. The flexible traffic control method considering road waterlogging distribution according to claim 1 is characterized in that: Step S1 is specifically as follows: S1.1: Use a laser point cloud acquisition device to collect continuous point cloud data of the road surface, wherein the point cloud data includes three-dimensional coordinate information and reflection intensity information; S1.2: Using a point cloud reconstruction algorithm, the point cloud data is processed to obtain a three-dimensional road model, thereby reconstructing the three-dimensional road surface model.

3. The flexible traffic control method considering road waterlogging distribution according to claim 1 is characterized in that: In step S2, the method for constructing the road waterlogging simulation model is specifically as follows: S2.1: Use CAD software to use the reconstructed 3D road surface model as the bottom surface of the fluid model, and select the range 1m above the bottom surface as the calculation area to create a solid model of the fluid domain; S2.2: Use the meshing function in the computational fluid dynamics software to mesh the geometric model; S2.3: Import the grid file into the computational fluid dynamics solver, complete the boundary conditions and model settings, and then solve it.

4. The flexible traffic control method considering road waterlogging distribution according to claim 3 is characterized in that: The road waterlogging simulation model includes rainfall simulation, road surface runoff simulation and road surface seepage simulation.

5. The flexible traffic control method considering road waterlogging distribution according to claim 1, characterized in that: In step S3, the specific method for determining the risk of hydroplaning is as follows: based on the simulation results, the critical hydroplaning speed corresponding to the water depth is calculated; the critical hydroplaning speed corresponding to the maximum water depth in the lane is compared with the lane speed limit; if the lane speed limit exceeds the critical hydroplaning speed corresponding to the water depth in the lane, it is considered that there is a risk of hydroplaning when driving at the lane speed limit in the lane.

6. The flexible traffic control method considering road waterlogging distribution according to claim 1, characterized in that: In step S4, the specific method of dividing the risk sections is: S4.1: Associating the simulation data based on the three-dimensional road model with the precise geographic location, and dividing each unit section at a certain interval along the lane direction; S4.2: Based on meteorological information, the road surface waterlogging situation during rainfall is simulated and calculated in real time, and the result is solved based on the hydroplaning speed at the maximum water depth in the unit section. If there is a hydroplaning risk in a unit section, the section is automatically marked as a risk section.

7. The flexible traffic control method considering road waterlogging distribution according to claim 1, characterized in that: Step S5 is specifically as follows: lowering the maximum speed limit of the marked risk section, and imposing a speed reduction requirement on the risk section and its preceding adjacent section according to the risk level, sending a deceleration instruction to vehicles traveling on the lane and not reaching the speed reduction buffer zone, and setting a temporary speed limit sign in the relevant area through an integrated traffic control system; forming a speed reduction buffer zone to ensure that vehicles can smoothly transition to the adjusted speed when entering or leaving the risk section.

8. The flexible traffic control method considering road waterlogging distribution according to claim 1, characterized in that: In step S6, the specific method of detour adjustment is: when the speed limit of the risk section of a lane is adjusted to a preset threshold and safety cannot be guaranteed, the section is marked as a high-risk section and the detour protocol is triggered; before reaching the speed reduction buffer zone, a detour instruction is sent to the vehicle traveling on the lane, and the traffic control system will automatically adjust the signal light cycle and green light time of the surrounding road network according to the detour demand, optimize the traffic flow of the detour route, and reduce the impact of the detour on the overall traffic flow.

9. The flexible traffic control method considering road waterlogging distribution according to claim 1, characterized in that: In step S7, the road closure measures are specifically as follows: when the proportion of high-risk sections in a lane exceeds a preset safety threshold, a closure instruction is sent through the traffic control system, the road closure facilities are activated, and the lane is closed; at the same time, the traffic control system guides vehicles through the information release system and traffic signal adjustment, and diverts them to other lanes or recommended detours.

10. The flexible traffic control method considering road waterlogging distribution according to claim 1, characterized in that: Step S8 is specifically as follows: when speed limit adjustment or road closure is adopted, real-time weather and road condition data of the area are continuously monitored; once the conditions of the risky road section improve and the critical hydroplaning speed rises back to a safe range, the speed limit or detour instruction is promptly revoked, the public and vehicles are notified through various communication channels, and the detour route is adjusted to optimize the traffic flow of the entire road network.

Images