Study On The Length Of Construction Control Zone On Urban Road Based On Safety And Efficiency

As one of the weakest links of urban road safety,occupying-road construction zone’s road resource is extremely tight,and it’ s traffic environment is more complex.Therefore,the problem of traffic safety and efficiency in this area is particularly intractable.Based on this,this paper collects the real data such as dynamic driving track and takes quantitative analysis of lane-changing behavior,which in occupying-road construction zone.Next,the conflict risk prediction model of implementing lane-changing process and lanechanging capacity model of closed lanes are established.Finally,conflict risks of lane-changing behavior under different driving tendency are calibrated by means of simulation.And lane-changing efficiency of various layout schemes in construction zone is also simulated.According to the results above,the best layout scheme of urban occupying-road construction zone under different conditions is put forward.Firstly,the difference between the actual layout of urban road construction zone and the standard one is compared.Then the traffic characteristic of this area is analyzed,and the influence of distance to the latest lane-changing point,condition of traffic flow,characteristic of the driver,vehicle type on lane-changing behavior in occupying-road construction zone is discussed respectively.After that,the vehicle movement data is recorded through aerial photography by the UAV.And 570 sets of effective lane-changing data are extracted though Tracker software.By means of the filter technique,the data has been cleaned.And then,statistical analysis of characteristic parameters such as duration of lane-changing,lane-changing speed and acceleration,gap available for insertion and position where vehicle starts lane-changing are carried out in detail.Moreover,the Spectral Clustering algorithm is used to divide driving styles into cautious type,moderate type and radical type.Secondly,based on conflict risk,security of lane-changing behavior is discussed.Six main variables which influence the compulsory lane-changing behavior are selected as the analysis factors of the conflict risk prediction model.Then,considering both the probability and severity,TTC(Time to Collision)and DRAC(Deceleration Rate to Avoid the Crash)are selected as the index to describe the conflict risk of compulsory lane-changing process respectively.On this basis,TTC and DRAC are used to construct a comprehensive index to calibrate the four conflict risk levels of compulsory lane-changing behavior.And this four conflict risk levels are considered as the dependent variable of the model.After that,the conflict risk prediction model of implementing compulsory lane-changing process in urban occupying-road construction zone is established.The probability of being at various level of conflict risk can be predicted by this model.Thirdly,based on lane-changing capacity,lane-changing efficiency is discussed.On the one hand,from the aspect of dynamics,gap available for insertion of lane-changing under different interactive driving scenarios is discussed.On the other hand,from the driver’s psychological characteristic,the lane-changing pressure at different parts of the closed lanes is analyzed.Based on the Erlang distribution,compulsive lanechanging capacity model of closed lanes under different occupying-road construction zone layout schemes is established.Especially,compulsive lane-changing capacity of which is lack of warning zone is further studied.Following this,the concept of lane-changing efficiency is put forward to analyze subsequent simulation results.Ultimately,the length of construction control zone is evaluated based on a comprehensive index which can reflect both the safety and efficiency of lane-changing behavior.Through MATLAB simulation,the change law of lane-changing efficiency and conflict risk level with the length of warning zone and upstream transition zone is summarized.Then a comprehensive index which can reflect both lane-changing efficiency and safety is constructed,and it is used to screen out the optimal length setting scheme of construction control zone under the condition of different traffic volume when the total lenghth of warning zone and transition zone is fixed.Given the above,this paper provides a theoretical basis for the layout of urban occupying-road construction zone.