CN-115455620-B - Calculation method of clear distance length recommended value of tunnel and intercommunication outlet

CN115455620BCN 115455620 BCN115455620 BCN 115455620BCN-115455620-B

Abstract

The invention provides a calculation method of a clear distance length recommended value of a tunnel and an intercommunication outlet, which comprises the following steps of constructing a VISSIM simulation model, respectively obtaining the headway, the speed and the instantaneous traffic flow density of different sections in the model, fitting to obtain the headway model and the speed distribution model of different lane sections, constructing a speed and density model and a critical pluggable gap model, constructing a safe lane change probability model by adopting a differential method, solving the safe lane change probability model based on a Monte Carlo simulation method according to various uncertainty factors, obtaining target lane change out success rates under different traffic volumes, large-scale vehicle proportions and clear distance lengths, and giving the clear distance length recommended value. The invention adopts the concept of certainty to calculate the problem of larger clear distance value required under traffic capacity, and utilizes a reliability design method to integrate traffic characteristics, driver characteristics and traffic safety requirements of a small clear distance road section into a whole, thereby providing a calculation method of clear distance length recommended value.

Inventors

LIU SHIYU
LIU CHANGHE
ZHANG CHI
SHI HUIJUN
ZHANG MIN
XIE ZILONG
ZHAO YIJING
WANG BO
XI SHENGYU

Assignees

西安长安大学工程设计研究院有限公司
西安长安大学工程设计研究院有限公司
长安大学
长安大学

Dates

Publication Date: 20260421
Application Date: 20220905
Priority Date: 20220905

Claims (6)

1. The method for calculating the recommended value of the clear distance length of the tunnel and the intercommunication outlet is characterized by comprising the following steps: Constructing a VISSIM simulation model of a tunnel and an intercommunication outlet, and calibrating by using measured data; Respectively obtaining the headway, the speed and the instantaneous traffic flow density of different sections in the VISSIM simulation model, and carrying out statistical fitting to obtain headway models and speed distribution models of different lane sections; The method comprises the steps of constructing speed and density models respectively under different traffic densities by using a K-means clustering algorithm, constructing a critical pluggable gap model according to the instantaneous traffic flow density and the vehicle position of a target lane, and selecting different critical pluggable gaps according to the influence degree of a barrier effect, wherein the formula is as follows: Wherein, the When the traffic flow density of the target lane is k, the critical insertable gap selected by the driver of the original lane; And Representing critical insertable gap maximum and minimum values, respectively, that are generally acceptable to the driver; determining a limit state mathematical model between the safe channel switching probability and the target channel switching probability, and constructing a safe channel switching probability model by adopting a differential method; The construction of the safe lane change probability model comprises the following steps: For a unidirectional double-lane, modeling is respectively carried out according to two situations of an inner lane and an outer lane of an initial vehicle position, and a probability model of inner lane safety by using a differential method is as follows: the safe lane change probability model of the outside lane shunting vehicle is as follows: Wherein S represents the distance that the shunting vehicle of the inner lane passes from the tunnel portal to the first time of lane change success, L is the clear distance length, To be critical the gap can be inserted, In order to be able to determine the vehicle speed, For the target lane speed, l is the first lane change transition length of the vehicle, l' is the second lane change transition length of the vehicle, 、、、 The model parameters are the model parameters of the headway; Taking the headway, the speed distribution, the speed, the density and the critical pluggable gaps as various uncertainty factors, and solving a safe lane change probability model based on a Monte Carlo simulation method to obtain target lane change running-out success rates under different traffic volumes, large-scale vehicle proportions and clear distance lengths; and according to the target lane change and exit success rate, the clear distance length recommended value under different traffic volumes and large-scale vehicle proportion is given.
2. The method for calculating a recommended value of a clear distance length between a tunnel and an interworking exit according to claim 1, wherein the calibrating using measured data comprises the steps of: under the condition of not considering weather factors, the measured speed of the small clear distance road section of the exit is collected by the vehicle type; and comparing the actually measured speed with the speed of the corresponding position output by the VISSIM simulation model, and calibrating the driving behavior parameters and the expected speed of the VISSIM simulation model.
3. The method for calculating the recommended value of the clear distance length of the tunnel and the intercommunication exit according to claim 1, wherein the steps of respectively obtaining the headway, the speed and the instantaneous traffic flow density of different sections in the VISSIM simulation model are as follows: the vehicle speed data collectors are distributed on different sections according to the VISSIM simulation model and are respectively positioned on main line sections corresponding to a tunnel outlet, a clear distance section middle point, a speed reduction lane gradual change section starting point and ending point, a speed reduction lane middle point and a speed reduction lane ending point; The method comprises the steps of respectively outputting and obtaining a file in a format of 'mer', 'fzp' of corresponding positions through each data collector, calculating and obtaining a headway by utilizing 'mer', obtaining the speed of corresponding moment and section and the positions of surrounding vehicles from 'fzp' according to the moment and section of 'mer' through Python software, and calculating the instantaneous traffic flow density of a certain section according to the positions of the vehicles.
4. The method for calculating the recommended value of the clear distance length of a tunnel and an intercommunication exit according to claim 1, wherein the fitting of the headway model and the speed distribution model of different lane sections comprises the following steps: adopting improved G-type statistics to remove abnormal values to obtain effective headway; By increasing correction factors Fitting the probability distribution of the headway of the small clear distance road section under different working conditions and the lane road section respectively; and (3) performing one-step fitting on model parameters under different working conditions to obtain different lane section headway models, wherein a Weibull distribution fitting is adopted for a speed distribution model.
5. The method for calculating a recommended value of a clear distance length between a tunnel and an interworking exit according to claim 1, wherein the constructing of the velocity and density model comprises the following steps: Dividing a speed interval, and performing iterative cluster analysis on two-dimensional data of the speed and the instantaneous traffic flow density of the same section by adopting a K-means clustering algorithm to obtain a corresponding cluster center so as to determine the relation between the speed and the density: , , , ; Wherein P (k a ) is taken as the probability of the occurrence of the density k a at a certain speed, the occurrence probability of the density k b is 1-P (k a ),C i and D i each represent the coefficient of a fitting polynomial, and n depends on the square sum of fitting correlation coefficients R 2 .
6. The method for calculating a recommended value of a clear distance length between a tunnel and an interworking exit according to claim 1, wherein the mathematical model of a limit state between the safe lane change probability and the target lane change probability is as follows: Wherein P (z) is a safe lane change probability, P T is a target lane change probability, g is a reliability function which can safely and successfully change lanes after the vehicle waits for a certain length distance z, g=0 represents a failure surface, and x i represents a variable which meets the safe or target lane change probability.

Description

Calculation method of clear distance length recommended value of tunnel and intercommunication outlet Technical Field The invention relates to the technical field of road traffic safety, in particular to a calculation method of a clear distance length recommended value of a tunnel and an intercommunication outlet. Background According to the topography of the west, the highways and the east in China, the topography and the geological conditions of mountain areas in the west area are complex, the fall between the mountain areas is large, the highway construction condition of part of road sections is difficult, under the limited condition, the tunnel distribution is more dense, and sometimes, the part of road sections have to be communicated with each other near the tunnel for the needs of linearity, cost, regional connection and the like, so that the distance between the tunnel and the intercommunication is too close. Under the influence of requirements such as tunnel portal light and shade adaptation and lane changing, the traffic flow condition of the small clear distance road section can be seriously disturbed, but as the combination design of the clear distance index and the traffic flow condition has no clear requirement, the combination design has no clear requirement on the recent and medium term of traffic capacity, the trouble of how to grasp the safety of a designer when facing the problem of the small clear distance can be caused, and how to take corresponding traffic safety guarantee measures aiming at the driving characteristics of the small clear distance road section is insufficient. Therefore, it is necessary to make more intensive study on traffic characteristics of the small clear distance road section of the tunnel and the intercommunication exit aiming at the specificity of the small clear distance road section, and further refine the selection of the clear distance length from the aspect of traffic flow condition so as to provide a new calculation method of the clear distance length recommended value. The clear distance length of the highway three-dimensional intersection design rule is a segmentation calculation clear adaptation process, an identification process, a track changing process and a safety confirmation process, all the used numerical values of the parts are deterministic, so that the road can be safely changed and driven out when the clear distance length of an exit road section meets a standard value, but actually, the traffic characteristic research on small clear distance of an exit through VISSIM can prove that most shunting vehicles can still safely and smoothly drive out of a main line when the clear distance length is smaller than the standard value, and the clear distance length researched by adopting the deterministic idea cannot reflect the vehicle driving-out probability of the small clear distance road section under different traffic flow conditions. Disclosure of Invention In order to solve the problems, the invention provides a calculation method of a clear distance length recommended value of a tunnel and an intercommunication outlet based on a reliability algorithm, which integrates traffic characteristics, driver characteristics and traffic safety requirements of a small clear distance road section into a whole so as to provide the clear distance length recommended value under different traffic volumes and large vehicle proportions. In order to achieve the above purpose, the present invention provides the following technical solutions. A calculation method of a clear distance length recommended value of a tunnel and an intercommunication outlet comprises the following steps: Constructing a VISSIM simulation model of a tunnel and an intercommunication outlet, and calibrating by using measured data; Respectively obtaining the headway, the speed and the instantaneous traffic flow density of different sections in the VISSIM simulation model, and carrying out statistical fitting to obtain headway models and speed distribution models of different lane sections; respectively constructing speed and density models under different traffic densities by using a K-means clustering algorithm; constructing a critical pluggable gap model according to the instantaneous traffic flow density of the target lane and the vehicle position; determining a limit state mathematical model between the safe channel switching probability and the target channel switching probability, and constructing a safe channel switching probability model by adopting a differential method; Taking the headway, the speed distribution, the speed, the density and the critical pluggable gaps as various uncertainty factors, and solving a safe lane change probability model based on a Monte Carlo simulation method to obtain target lane change running-out success rates under different traffic volumes, large-scale vehicle proportions and clear distance lengths; and according to the target lane change and exit su