CN102542831B - Variable speed-limit control method of expressway based on real-time traffic flow and weather information - Google Patents

Abstract

A variable speed limit control method for express roads based on real-time traffic flow and weather information, according to real-time changes in road traffic flow and weather conditions, automatically adjusts the speed limit value under various traffic flows and weather conditions, and through variable information The board will release the speed limit information to the driver, thereby reducing the risk of traffic accidents and improving road traffic safety. The present invention uses traffic flow detection equipment and meteorological environment detection equipment to obtain real-time traffic flow and weather characteristic parameters, and automatically adjusts the road speed limit value according to various traffic flow and weather conditions, overcoming the fact that the existing road speed limit value can only be fixed defects and deficiencies. The dynamic speed limit method based on real-time traffic flow and weather information has practical engineering application value in expressway traffic management and control.

Description

A variable speed limit control method for expressways based on real-time traffic flow and weather information

technical field

The invention belongs to the technical field of traffic intelligent management and control, performs dynamic speed limit control on expressways according to real-time traffic flow and weather conditions, and is a variable speed limit control method for expressways based on real-time traffic flow and weather conditions.

Background technique

Highway speed limit has always been a hot issue in traffic safety. According to the 2005 and 2006 "Annual Report on Traffic Accidents of the Ministry of Public Security of the People's Republic of China", about 10% of the accidents from 2005 to 2006 were related to vehicle speeding, ranking first among various accident causes. Previous studies have shown that higher driving speeds lead to higher collision risk and accident severity, because under high-speed driving conditions, drivers do not have enough reaction time to take corresponding measures to avoid dangerous situations, such as sudden braking and acceleration of the vehicle in front, other vehicles Enter the driveway. Therefore, under specific road and environmental conditions, if the driver drives at a reasonable speed, road safety can be significantly improved.

The operating state of road traffic flow changes in real time, while the traditional road speed limit value is a fixed value, which cannot be dynamically adjusted according to the real-time road traffic flow operating conditions. In some traffic flow states, the traffic flow is large and the vehicle speed is low, but the speed limit value is still a high speed limit value, which leads to the excessive speed of some vehicles and increases the speed difference between vehicles, thereby increasing the accident risk. In addition, because the driver cannot understand the road traffic status ahead (such as congestion and queuing, etc.), it is easy to drive too fast, and it is too late to slow down when he notices the traffic problem ahead, thereby inducing traffic accidents. Therefore, the variable speed limit control method of expressway according to the operating state of traffic flow has attracted the attention of many foreign traffic scholars in recent years.

Adverse weather will not only have a negative impact on the safe operation of the vehicle, but also significantly affect the driver's reaction time. For example, in foggy days, due to poor vision, the driver needs longer to recognize the distance from the vehicle ahead, so the speed limit in bad weather Different from the usual speed limit. Unreasonable speed in bad weather can easily lead to road traffic safety accidents. Studies have shown that the number of bad weather accidents per unit time in bad weather is several times or even dozens of times that of sunny days, and most of them are major and vicious accidents. In 2007, traffic accidents in bad weather caused about 17,600 deaths and 85,200 injuries across the country, with direct property losses amounting to RMB 318 million. Therefore, it is important and practical to study the speed limit of highways in bad weather to ensure road safety, and more and more traffic scholars at home and abroad are devoted to the research of road safety in bad weather. Adverse weather includes: fog, rain, snow, wind, etc.

With the application of the current Intelligent Transportation System (ITS) intelligent transportation system and Advanced Transportation Management System (ATMS) advanced traffic management system, the traffic control center can obtain real-time and accurate traffic flow and weather data through traffic flow and weather monitoring equipment, such as the current Speed, flow, occupancy, temperature, visibility, rainfall, road conditions, wind force and direction, etc. The acquisition of traffic flow and weather state data has laid a good foundation for the implementation of dynamic variable speed limit control based on real-time traffic flow and weather information. Use various parameter values detected by traffic flow and weather monitoring equipment to calculate the reasonable speed limit value of the current expressway, and release it to the driver in real time to reduce the speed of vehicles on the road. Engineering application value.

Contents of the invention

The problem to be solved by the present invention is: the traditional road speed limit value is a fixed value, which cannot be dynamically adjusted according to the real-time road traffic flow operation situation. According to the dynamic speed limit control method and weather conditions, the speed limit value of the expressway can be adjusted in real time according to the changing traffic flow and weather conditions, so as to improve driving safety.

The technical solution of the present invention is: a variable speed limit control method for express roads based on real-time traffic flow and weather information, the speed limit value of express roads is controlled by the control system, and the control system includes detection equipment, a background central computer and an electronic information board , the detection equipment and the electronic information board are set on the expressway, and the variable speed control method is as follows:

1) Set up traffic flow and weather information detection equipment on the expressway to collect traffic flow and weather information in the area where the road to be controlled is located. Traffic flow information includes speed, flow and occupancy rate, and weather information includes visibility, rainfall, road surface status and wind force Wind direction information, the detection accuracy is once every 5 minutes;

2) Transmit the detected parameters to the background central computer, and judge the current time at the same time. The control system only controls the speed limit value during the time period of 7:00-19:00 a day. If it is not within this time period, then "Keep speed, drive safely" is displayed on the electronic information board;

3) According to the real-time traffic flow detected by the coil, it is judged whether the traffic flow is in a non-free flow state. When the average traffic flow density of each lane within 5 minutes detected by the traffic flow parameter detection equipment is greater than 18pcu/km/lane, the variable limiter is activated. Speed control system, otherwise, the electronic information board will display the default speed limit value of the expressway; when the difference between the 85% vehicle speed detected by the traffic flow parameter detection equipment and the current speed limit value is greater than or equal to 5km/h within the 5-minute detection period , the variable speed limit control system automatically adjusts the speed limit value to the current speed limit value plus 10km/h; when the difference between the 85% vehicle speed detected by the traffic flow parameter detection equipment and the current speed limit value within the detection period is less than or equal to -5km /h, the variable speed limit control system automatically adjusts the speed limit value to the current speed limit value minus 10km/h; when the absolute value of the difference between the 85% vehicle speed detected in the detection cycle and the current speed limit value is less than 5km/h When , the current speed limit value is not adjusted;

4) According to the meteorological parameters detected by the weather monitor, it is judged whether there is a bad weather condition, so as to determine whether to start the variable speed limit control; the detected meteorological parameters are transmitted to the background central computer, and the optimal limit is automatically calculated according to each meteorological parameter. Speed value: Calculate the visibility speed limit value according to the road visibility, calculate the rainfall speed limit value according to the rainfall situation, calculate the icing speed limit value according to the icing state of the road surface, and calculate the wind force speed limit value according to the wind force and wind direction. Compare the 4 speed limit values, and take the lowest speed limit value as the meteorological safety speed limit value of the current expressway;

5) Take the lower value among the speed limit values calculated according to the traffic flow state and bad weather conditions as the current safe speed limit value;

6) compare the current safe speed limit value calculated in step 5) with the maximum and minimum allowable speed limit values of the expressway, and judge whether the current safe speed limit value needs to be adjusted; If it is not between the maximum and minimum allowable speed limit values, then select the highest speed limit value among the maximum and minimum allowable speed limit values. The value of the current safe speed limit value close to step 5) is released as the optimal speed limit value under the current conditions;

7) After completing a cycle of 5 minutes of detection, the control system automatically detects the traffic flow and weather conditions in the next cycle, and dynamically adjusts the optimal speed limit value according to the actual road traffic and weather conditions for release.

When the expressway has multiple sections with different speed limit values, each section is subject to variable speed limit control, starting from the last section of the expressway with variable speed limit control, and detecting the limit between it and the adjacent upstream variable speed limit control section. Speed value difference, the speed limit value difference between two adjacent variable speed limit control road sections is less than or equal to 20km/h, otherwise reduce the speed limit value of the road section with a higher speed limit value, the process until the detection reaches the first speed limit of the expressway At the end of each variable speed limit control section, determine the optimal speed limit value of each variable speed limit control section.

Compare the determined optimal speed limit value of each variable speed limit control section with the current actual speed limit value of each section, if the difference between the optimal speed limit value of each variable speed limit control section and the actual speed limit value of each section is greater than 10km /h, then adjust, and the step length of each adjustment of the speed limit value shall not exceed 10km/h;

The determined speed limit value of each road section is released through the roadside electronic variable information board to realize the variable speed limit control of the expressway based on real-time traffic flow and weather information.

When the traffic flow and weather conditions detected by the traffic flow and weather detector become good, the variable speed limit adjustment control system is turned off, and the speed limit value of the expressway is restored to the initial default value, that is, the maximum speed limit value of the road section.

The invention discloses a variable speed limit control method for express roads based on real-time traffic flow and weather information. The detection system collects the real-time traffic flow and weather state of the road according to a certain period through the traffic flow and weather monitoring equipment; according to the collected traffic flow and weather information Weather parameters, calculate the optimal speed limit value under the current traffic flow and weather conditions, and judge whether to enable variable speed limit control; if variable speed limit control is enabled, the roadside variable information board will issue a new speed limit value, if If the system is not started, it enters the next cycle and judges according to the conditions of the next cycle. The invention has the advantage of using traffic flow and weather monitoring equipment to obtain real-time traffic flow and weather conditions for dynamic speed limit adjustment, which overcomes the defect and deficiency that the previous speed limit value cannot be adjusted according to changing traffic flow and weather conditions. Therefore, this method has practical engineering application value in dynamic speed limit management and control based on real-time traffic flow and weather conditions.

Description of drawings

Figure 1 is a flow chart of variable speed limit control startup judgment.

Figure 2 is a flow chart for calculating reasonable speed limit values under adverse weather conditions.

Fig. 3 is a flow chart of determining a reasonable speed limit value according to the traffic flow state.

Detailed ways

The present invention proposes a variable speed limit control method for express roads based on real-time traffic flow and weather information, including the following steps:

1) Set up traffic flow and weather information detection equipment on the expressway to collect traffic flow and weather information in the area where the road to be controlled is located. Traffic flow information includes speed, flow, occupancy rate, and weather information includes visibility, rainfall, road surface status, wind force For wind direction information, the detection accuracy is once every 5 minutes.

2) Transmitting the detected parameters to the central computer. At the same time, the current time is judged, and the variable speed limit control system only plays a control role in the daytime (7:00AM-7:00PM) time period. If it is not within this time, the electronic information board will display "keep speed, drive safely".

3) According to the real-time traffic flow detected by the coil, it is judged whether the traffic flow is in a non-free flow state. When the average traffic flow density of each lane within 5 minutes detected by the traffic flow parameter detection equipment is greater than 18pcu/km/lane, the variable limiter is activated. Speed control system, as shown in Figure 1, otherwise, the electronic information board displays the default speed limit value of the expressway; when the difference between the 85% vehicle speed detected by the traffic flow parameter detection equipment and the current speed limit value is greater than or When it is equal to 5km/h, the variable speed limit control system automatically adjusts the speed limit value to the current speed limit value plus 10km/h; Or equal to -5km/h, the variable speed limit control system automatically adjusts the speed limit value to the current speed limit value minus 10km/h; when the absolute value of the difference between the 85% vehicle speed detected in the detection cycle and the current speed limit value When it is less than 5km/h, the current speed limit value will not be adjusted;

4) Judging whether bad weather conditions occur according to the meteorological parameters detected by the weather monitor, so as to determine whether to start the variable speed limit control, as shown in Figure 2; the detected meteorological parameters are transmitted to the background central computer, and automatically Calculate the optimal speed limit value: calculate the visibility speed limit value according to the road visibility, calculate the rainfall speed limit value according to the rainfall situation, calculate the icing speed limit value according to the icy state of the road surface, and calculate the wind force speed limit value according to the wind force and wind direction value, compare the calculated four speed limit values, and take the lowest speed limit value as the current meteorological safety speed limit value of the expressway;

5) Take the lower value among the speed limit values calculated according to the traffic flow state and bad weather conditions as the current safe speed limit value;

6) compare the current safe speed limit value calculated in step 5) with the maximum and minimum allowable speed limit values of the expressway, and judge whether the current safe speed limit value needs to be adjusted; If it is not between the maximum and minimum allowable speed limit values, then select the highest speed limit value among the maximum and minimum allowable speed limit values. The value of the current safe speed limit value close to step 5) is released as the optimal speed limit value under the current conditions;

7) After completing a cycle of 5 minutes of detection, the control system automatically detects the traffic flow and weather conditions in the next cycle, and dynamically adjusts the optimal speed limit value according to the actual road traffic and weather conditions for release.

When the expressway has multiple sections with different speed limit values, each section is subject to variable speed limit control, and the difference between the speed limit values of each control section needs to be kept within a certain range to prevent the large gap between the upstream and downstream speed limit values from affecting the traffic flow. Disturbance, that is, the wire control stage shown in Figure 3, the present invention starts from the section of the last variable speed limit control section of the expressway, and detects the difference between the speed limit value of it and the adjacent upstream variable speed limit control section, and the two phases The speed limit value difference between adjacent variable speed limit control road sections is less than or equal to 20km/h, otherwise the speed limit value of the road section with a higher speed limit value is reduced, and the process ends until the detection reaches the first variable speed limit control road section of the expressway , to determine the optimal speed limit value of each variable speed limit control section.

In order to avoid excessive changes in the speed limit value of each road section, compare the determined optimal speed limit value of each variable speed limit control section with the current actual speed limit value of each road section, if the optimal speed limit value of each variable speed limit control section If the difference from the actual speed limit value of each road section is greater than 10km/h, it will be adjusted, and the step size of each adjustment of the speed limit value should not exceed 10km/h;

The determined speed limit value of each road section is released through the roadside electronic variable information board to realize the variable speed limit control of the expressway based on real-time traffic flow and weather information.

When the traffic flow and weather conditions detected by the traffic flow and weather detector become good, the variable speed limit adjustment control system is turned off, and the speed limit value of the expressway is restored to the initial default value, that is, the maximum speed limit value of the road section.

After determining the reasonable speed limit value under the traffic flow operation state, the central computer issues an instruction to adjust the electronic variable information board on the roadside, and releases the new speed limit information to the driver. At the same time, corresponding warning information can be issued to the driver, such as "congestion ahead, slow down" and so on.

Since this method can dynamically adjust the reasonable speed limit value of expressway according to real-time traffic flow and weather information, this method has practical engineering application value in expressway traffic management and control.

Claims (4)

1. the through street variable speed-limiting control method based on arithmetic for real-time traffic flow and Weather information, it is characterized in that by control system, the speed limit of through street being controlled, control system comprises checkout equipment, backstage central computer and electronic intelligence plate, checkout equipment and electronic intelligence plate are arranged on through street, and variable-ratio control method is:

1) traffic flow and Weather information checkout equipment are set on through street, collect traffic flow and the Weather information of road to be controlled region, telecommunication flow information comprises speed, flow and occupation rate, Weather information comprises visibility, rainfall, pavement state and wind direction information, and accuracy of detection is to detect once for every 5 minutes;

2) parameters detecting is transferred in the central computer of backstage, judge current time, control system is only carried out speed limit control at the 7:00-19:00 of a day in the time period simultaneously, if not at this moment between in section, on electronic intelligence plate, show " keeping the speed of a motor vehicle, safety traffic ";

3) the arithmetic for real-time traffic flow situation detecting according to coil judges that whether traffic flow is in non-freestream conditions, when traffic flow parameters detection equipment Inspection to 5 minutes in each track traffic flow average density while being greater than 18pcu/km/lane, start variable speed-limit control system, otherwise electronic intelligence plate shows this through street acquiescence speed limit; In the sense cycle of 5 minutes traffic flow parameters detection equipment Inspection to 85% speed of a motor vehicle and the difference of current speed limit while being more than or equal to 5km/h, it is that current speed limit adds 10km/h that variable speed-limit control system regulates speed limit automatically; In sense cycle traffic flow parameters detection equipment Inspection to 85% speed of a motor vehicle and during current be less than or equal to-5km/h of speed limit value difference, it is that current speed limit subtracts 10km/h that variable speed-limit control system regulates speed limit automatically; When the absolute value of 85% speed of a motor vehicle detecting and the difference of current speed limit is less than 5km/h, do not regulate current speed limit in sense cycle;

4) meteorologic parameter detecting according to weather monitoring device judges whether to occur poor weather, thereby determine whether to start variable speed-limit, controls; The meteorologic parameter detecting is transferred in the central computer of backstage, according to each meteorologic parameter, automatically calculate optimum speed limit: according to road state of visibility, calculate visibility speed limit, according to rainfall situation, calculate rainfall speed limit, according to state computation icy on road, go out icing speed limit, according to wind direction situation, calculate wind-force speed limit, 4 speed limits that calculate compare, and get value that wherein speed limit is minimum as the meteorological safety speed-limit value of current through street;

5) get according to lower value in the speed limit calculating under traffic flow modes and poor weather as current safety speed limit;

6) by step 5) the current safety speed limit that calculates and through street is the highest and minimum permission speed limit compares, judge whether current safety speed limit needs to regulate; As current safety speed limit as described between the highest and minimum speed limit, with this speed limit, can be used as optimum speed limit under precondition and issue; If not between the highest described and minimum permission speed limit, in the highest and minimum permission speed limit, select to approach most step 5) the value of current safety speed limit as optimum speed limit under precondition, issue;

7) after completing the one-period detection of 5 minutes, control system detects traffic flow and state of weather in next cycle automatically, dynamically adjusts optimum speed limit issue according to real road traffic and weather condition.

2. the through street variable speed-limiting control method based on arithmetic for real-time traffic flow and Weather information according to claim 1, it is characterized in that having when through street the section of the different speed limits of multistage, every section is carried out respectively variable speed-limit control, the section of being controlled by through street final stage variable speed-limit starts, detect itself and adjacent upstream variable speed-limit and control speed limit poor in section, two adjacent variable speed-limits are controlled speed limit value difference between section and are less than or equal to 20km/h, otherwise reduce the speed limit in the section that speed limit is higher, this process until detect reaches first variable speed-limit of through street and to control section and finish, determine the optimum speed limit in each variable speed-limit control section.

3. the through street variable speed-limiting control method based on arithmetic for real-time traffic flow and Weather information according to claim 2, it is characterized in that each optimum speed limit in variable speed-limit control section and the actual speed limit in current each section determined to compare, if each variable speed-limit is controlled the difference of the optimum speed limit in section and each actual speed limit in section and is greater than 10km/h, adjust, adjust speed limit change step at every turn and be no more than 10km/h;

Each section speed limit of determining is issued by trackside electronic variable advices plate, realized according to the through street variable speed-limit of arithmetic for real-time traffic flow and Weather information and controlling.

4. the through street variable speed-limiting control method based on arithmetic for real-time traffic flow and Weather information according to claim 1, it is characterized in that the traffic flow that detects when traffic flow and weather detecting device and state of weather become when good, close variable speed-limit regulation and control system, through street speed limit reverts to initial default value, i.e. section Maximum speed limit value.

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