Method for determining step-by-step speed limit value of exit ramp of freeway

Abstract

The invention relates to a method for determining a step-by-step speed limit value of an exit ramp of a freeway, belonging to the field of traffic operation management of the freeway. The method comprises the following steps: dividing a speed characteristic value of the exit ramp into three site vehicle speeds, including a ramp nose end part, a transition section starting point and a reasonable outer side mainline of an exit ramp upstream section, through a research on running vehicle speed and deceleration of the exit ramp upstream section; deducing a running speed of the transition section starting point according to a ramp nose end speed limit value, continuously deducing a vehicle speed of the reasonable outer side mainline lane, combining an investigated or predicted mainline vehicle running speed to acquire a speed limit value calculation model and a corresponding calculation formula, finally determining a final step-by-step speed limit value according to engineering experience. Based on verification results of the method disclosed by the invention in combination with examples, the method disclosed by the invention has the advantages of simple and convenient calculation, high precision, suitability for engineering practical application and the like, effectively solves the shortcomings of the prior art and can be widely applied to the traffic operation management of the freeway.

Description

technical field [0001] The invention relates to a method for determining step-by-step speed limit values ​​of expressway exit ramps, and belongs to the field of expressway traffic operation management. Background technique [0002] The step-by-step speed limit in the upstream section of the exit ramp of the expressway refers to the two-level speed limit control of vehicles within the range of the exit ramp. Among them, the speed limit on the outer side of the main line is the first level, and the speed limit at the nose of the ramp is the second level. After research, it is found that under the condition that there is only a single-stage speed limit at the nose of the ramp, the driving speed of the vehicle is not easy to drop, and the speed of the vehicle entering the exit ramp is too fast, which is likely to cause traffic accidents. Therefore, through the advance speed limit control of the outer lane of the main line, it is ensured that the vehicle enters the off-ramp at a...

AI Technical Summary

Problems solved by technology

[0019] From the above background technology, it is not difficult to see that the reasonable speed limit control methods of expressways are studied from different angles at home and abroad, but the research area of ​​these two types of methods is the main line of the expressway, and the vehicle speed and deceleration characteristics of the off-ramp area are not studied. make an analysis

In engineering practice, the determination of the speed limit value of the ramp and the main line often lacks scientific basis, and there are potential safety hazards

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