Control of Heavy-Duty Trucks: Environmental and Fuel Economy Considerations

In this project we investigate the effect of heavy-duty trucks, equipped with different Adaptive Cruise Control (ACC) systems, operating in mixed traffic with manually driven passenger vehicles, on the environment and traffic flow characteristics. The sluggish dynamics of trucks whether manual or ACC that is due to their limited acceleration capabilities filters speed disturbances caused by leading vehicles and lead to beneficial effects on the environment and traffic flow characteristics. This response however may lead to higher travel times in certain situations as well as invite cut-ins from neighboring lanes causing additional disturbances. A new ACC design that is developed and experimentally tested reduces some of the negative effects of trucks in mixed traffic. Executive Summary This is the Final Report for TO4203. In this project we investigated the effect of trucks, manually driven as well as with different Adaptive Cruise Control (ACC) systems in mixed traffic on the environment and traffic flow characteristics. We used driver models to simulate human driving and validated truck dynamical models for simulations and ACC design. Experiments involving actual vehicles are carried out in order to validate the models used. Emissions models for passenger vehicles and trucks developed by the group of Professor Matthew Barth of the University of California at Riverside are used to study the effect of trucks in mixed traffic on the fuel economy and pollution. A new ACC design for trucks is developed that has better properties than existing ones with respect to impact on the environment and performance. The main findings of this project are as follows: 1. The sluggish dynamics of trucks whether manual or ACC due to limited acceleration and speed capabilities make their response to disturbances caused by lead passenger vehicles smooth. The vehicles following the truck are therefore presented with a smoother speed trajectory to track. This filtering effect of trucks is shown to have beneficial effects on fuel economy and pollution. The quantity of these benefits depends very much on the level of the disturbance and scenario of maneuvers. For example if the response of the truck is too sluggish relative to the speed of the lead vehicle then a large intervehicle spacing may be created inviting cut ins from neighboring lanes. These cut-ins create additional disturbances with negative effects on fuel economy and pollution. Situations can be easily constructed where the benefits obtained due to the filtering effect of trucks are eliminated due …