A Research On Vehicle Emission Characteristics And Setting Technologies For Freeway Work Zone

With the rapid development of the economics in China,six lanes and eight lanes freeways increase gradually.In the future,the multi-lane freeways will become an inevitable trend.In addition,with the increase in the ownership of motor vehicles,many existing freeways in some cities have not meet the predicted traffic demand,which results in its early damage seriously and the maintaining works increase continuously.The setting of work zones will certainly have an impact on the traffic flow,which also to some extend affect the exhaust emissions of motor vehicles.However,few studies in China explored the vehicle emission characteristics of the freeway work zones.Existing researches of freeway work zones are limited to analyze the safety characteristic and the traffic delay.Thus,the purpose of this paper is to analyze the vehicle emission characteristics of the multi-lane freeway work zones by using the simulation method and study the setting technology of the multi-lane freeway work zones.Firstly,this paper introduces the composition of each multi-lane freeway work zone and mainly analyzes the setting methods of the typical six lane and eight lane freeway work zones to determine the factors needed to be considered in the design of freeway work zones.In addition,this paper explores the traffic flow,road and driving characteristics of freeway work zones and points out the existing problems in the setting freeway work zone.Secondly,in order to understand the vehicle emission characteristics of the multi-lane freeway work zones,two models including VIS SIM micro simulation model and MOVES emission model are chosen.This paper proposed an approach to establish a vehicle exhaust emission simulation platform of multi-lane freeway work zones by combining VISSIM model with MOVES emission model.By using this platform,the vehicle emission characteristics through the multi-lane freeway work zones are obtained.Moreover,several traffic parameters and road attributes are changed to analyze the influence of these changed factors on the vehicle emission rates through multi-lane freeway work zones.Finally,based on the traffic flow theory,this paper divides the traffic flow into the free flow and the forced flow and put forward a method which can be used to design the warning area length of the multi-lane freeway work zone.In addition,this paper combines the multi-objective evaluation method with the simulation model of the multi-lane freeway work zone to obtain the optimal speed limit value of the typical six lane and eight lane freeway work zones.