Assessing the impact of autonomous vehicles on signalized intersection efficiency and pavement life cycle

Abstract

Vehicle automation is the new trend in transport systems development. Autonomous Vehicles (AVs) technology is progressing to define the new industry paradigm for full driverless vehicles. However, the impacts of AVs are limitedly explored, and full-scale operational tests of significance to understand the implementation requirements for this technology and potentially acquaint the process of transport systems planning. In this research, the operational performance of signalized intersections is investigated with the various penetration rates of AVs. Four variables are of interest to observe the impact of AVs; the start-up delay value, the saturation headway, the initial response time, and, the number of vehicles until the saturation headway is reached. The research also takes into consideration the impacts of AVs on intersection efficiency, under various geometric and operational effects such as; critical lane movement and autonomous vehicle level of automation. The main factors of significance are recorded using the Microscopic modelling tool for traffic analysis; PTV Vissim. As the simulated vehicle queue dissipates at the intersection's stop line, the discharge headway is recorded, and hence the discharge headway models are created. The data recording and extraction is proceeded with the assessment of the signalized intersection operational performance in terms of the signalized intersection capacity, and the average movement control delay and subsequent Level of Service (LOS).

The research also studies the impact of AVs on the overall pavement life cycle. A service life assessment of the pavement is undertaken to study the effect of AVs on the fatigue failure of the pavement undergoing the repetitive loading due to the channelized wheelpath of AVs with zero lateral wandering. Thus, the fatigue failure of the pavement structure is studied at various AV%. The AVs impact on the road infrastructure is assessed via the vehicular traffic loading application on an HMA flexible pavement structure using the AASHTOWare Pavement ME Design software. Lastly, an interdisciplinary Benefit - Cost comparative analysis is undertaken to quantifiably evaluate the delay improvements vs. the infrastructure cost implications in the transport system as AVs% gradually increase in the traffic flow. The research results show that the increase of AV% incorporation with the flow does not immensely improve the startup delay, decreases the saturation headway, and improves uniformity of the traffic flow. Randomness is noted at mixed traffic flow conditions in terms of initial discharge headway. The overall signalized intersection's efficiency improves in terms of the interstation's capacity and average movement control delay. On the other hand, with regards to the road infrastructure assessment, the AV% increase results in a shorter pavement service life because of fatigue damage due to the reduction of lateral wandering. Accordingly, the cost implications on the infrastructure are induced via the AVs presence within the traffic flow, yet the induced pavement costs are minimal in comparison to the user benefits due to delay reduction.