Optimization Of Hard Shoulder Running On Highways

Opening the hard shoulder for running traffic during peak hours or incident times has been in operation on several highways in European and USA.This paper focuses on the optimization of hard shoulder running and the strategy with others.First of all,this paper introduces the concept of active traffic management(ATM)and ATM strategies,such as hard shoulder running(HSR),speed harmonization,queue warning etc.It summarizes the types and profit of HSR and the advantages and drawbacks of HSR design alternatives based on cases on several highways in United Kingdom,Germany,and Netherlands.Then it summarizes summarizes a number of potential limitations and problems in the operation of HSR.A new algorithm for optimizing HSR on highways was proposed,which aims to minimum the total time spent(TTS)in the whole network.The algorithm utilizes genetic algorithm and sliding windows technique to forecast and optimize the operation of HSR on different constraint conditions and target functions,while the highways are established based on METANET model.At last,the strategy is tested on the I-80 E highway in California.The experimental results show that when the change frequency of HSR is less than or equal to 14 during a sliding window and the weight coefficient of the closure is 0.5,the TTS is reduced by 30.61%,which is better than TTS of all-time operation or during the volumes exceed a predetermined threshold.Then,it optimizes HSR through reducing the traffic breakdown probabilities of a congested traffic network in coordination with speed harmonization.Firstly,it defines traffic breakdown based on literature.Then,it detects the breakdown events through the flow,speed,or occupancy from the study case which is divided into three factors——basic segment,on-ramp merging segment and off-ramp diverging segment.Breakdown probabilities can be generated from empirical observations.It put forward the breakdown probabilities distribution model based on highway traffic volume,hard shoulder volume and ramp volume based on empirical probabilities.At last the speed harmonization strategy based on the breakdown probabilities is tested on M42 highway in United Kingdom.At last,this paper has a research on optimizing HSR in coordination with queue warning during non-recurring traffic incidents with cell transmission model.It improves CTM with the the loss of capacity owing to incident.When a driver receive queue warning,he will change the lane into others,and the desired lane-changing rate will change.This paper utilizes a utility function to simulate the choice.An algorithm for optimizing HSR on highways iswas proposed,which aims to minimum the total time delay(TTD).In summary,the optimization of hard shoulder running on highways increases the capacity,while the total time delay and breakdown probabilities decrease.