Research Of Overtaking Model On Two-Lane Highway Simulation

It is very important to study overtaking model for analyzing two-lane highway capacity, evaluating the level of service, researching traffic safety and promoting traffic flow theory. This paper studies overtaking model systemically, aiming the situation of the two-lane highway presently in China, based on the field data collection and analysis, using the research method that lookup literature—analysis—modeling—calibration—validation—application.This paper presents the history and up-to-date fruits of overtaking models. The tendency of the research is also discussed through analyzing various models. This paper describes the whole course of overtaking and establishes overtaking model based on analyzing the characteristic on two-lane highway in China. In the model, the course of overtaking is divided into five steps:"having overtaking desire","determining overtaking type","checking overtaking requirement","executing overtaking"and"stopping overtaking to return forcibly".This paper analyzes the parameter of the model, brings out overtaking sight distance estimate coefficient and offers the calculation method of the coefficient. One of the overtaking requirements that overtaking sight distance is less than the space between overtaking vehicle and opposite oncoming vehicle is modified to that the product of overtaking sight distance and overtaking sight distance estimate coefficient is less than the space between overtaking vehicle and opposite oncoming vehicle.The acceptable return clearance and the acceptable return spacing are calibrated by analyzing field data, which came from overtaking experiment. The value extension of acceptable return clearance and acceptable return spacing are confirmed. This paper consider that time headway which beginning to determine the overtaking desire is reflect the situation of the vehicle's non-freedom. And the recommendatory time headway is 3.1s. The model is validated making use of comparing the field data with the simulation result.The model is used to make simulation experiment. By analyzing relation of speed-volume, relation of overtaking ratio-volume and relation of follow ratio(delay ratio)-volume, the capacity of the two-lane Highways capacity is calculated as 2900 pcu/h under standard conditions. And the contrast simulation experiment is made by TWOPAS.