Impact of Level 3 Automated Vehicle Merging on 2-To-1 Lane Freeway

Abstract

EXECUTIVE SUMMARY The better of automated system is continuously developed for vehicles. It is becoming to the new generation of vehicle that could drive by itself without human driver. Recently, the level 3 automated vehicle is being developed by many manufactures and it is soon expected to be applicable on roadway. The level 3 automated vehicle is firstly expected to travel on roadway concurrently with the manual vehicle and could be fully used in the future. Two-lane highways play an important role of mobility in the state and county highway systems. The maintenance or reconstruction of roadway are required because of the limited life cycle of the pavement. The capacity could significantly drop due to the lane closer from the work zone.Many strategies are used to control the traffic to efficiently and safely pass through the work zone. The static early merge, late merge and hybrid are used in this study. Early merge allows vehicle to change lane to the open lane before reaching the merge point where the closed lane before the merge point is not being used by vehicle. Late merge allows vehicle to stay on its lane until the merge point and perform alternative merge or zipper merge pattern. Hybrid strategy is the combination of early merge and late merge strategies which allows vehicle to merge whenever it finds acceptable gap to change lane to open lane. Vehicle could continue moving to the merge point when the gap is not sufficient and perform the alternative merge pattern. This study aims to investigate the impact of level 3 automated vehicle passing through the work zone on 2-to-1 lane drop freeway. The different traffic flow and market penetration of level 3 automated vehicle varies in each simulation. Three merging strategies is simulated to find the best practice between early merge, late merge and hybrid strategies. The simulation model is created by using VISSIM microsimulation tool. The total of 90 simulations with three merging strategies at different traffic flow and market penetration are performed. The traffic flow varies from 1,000 vphpl to 2,000 vphpl with incremental of 200 vphpl. The market penetration varies from 40% to 100% with incremental of 20% and the other 0% is also applied. Two performance of vehicle throughput and travel time are investigated in the simulation. After running all the simulations and analyzing the results, it could be found that the level 3 automated vehicle helps improve the mobility performance. The higher market penetration of level 3 automated vehicle causes the higher vehicle throughput and less travel time. It has significant impact on early merge and hybrid strategies but only slightly impact to late merge strategy. From three merging strategies, the hybrid strategy is the best practice for vehicle with mix traffic of level 3 automated vehicle passing through the work zone on 2-to-1 lane drop freeway.