Coordinating Vehicle Platoons for Highway Bottleneck Decongestion and Throughput Improvement

Truck platooning is a technology that is expected to become widespread in the coming years. Apart from the numerous benefits that it brings, its potential effects on the overall traffic situation need to be studied further, especially at bottlenecks and ramps. Assuming we can control the platoons from the infrastructure, they can be used as controlled moving bottlenecks, actuating control actions on the rest of the traffic, and potentially improving the throughput of the whole system. In this work, we use a tandem queueing model with moving bottlenecks as a prediction model to calculate control actions for the platoons. We use platoon speeds and formations as control inputs, and design a control law for throughput improvement of a highway section with a stationary bottleneck. By postponing and shaping the inflow to the bottleneck, we are able to avoid capacity drop, which significantly reduces the total time spent of all vehicles. We derived the estimated improvement in throughput that is achieved by applying the proposed control law, and tested it in a simulation study, with multi-class cell transmission model with platoons used as the simulation model, finding that the median delay of all vehicles is reduced by 75.6% compared to the uncontrolled case. Notably, although they are slowed down while actuating control actions, platooned vehicles experience less delay compared to the uncontrolled case, since they avoid going through congestion at the bottleneck.

I. Introduction

With truck platooning progressing towards becoming a commonplace technology [1], understanding the impact it will have on the overall traffic is becoming increasingly important. Apart from its traditional primary purpose of providing potential fuel savings through air drag reduction [2], truck platooning is also expected have a positive impact on traffic efficiency through reducing the headways between vehicles [3], alleviating the adverse effect trucks have on the traffic [4]. Although there have been numerous field tests of truck platooning in real traffic [5], insufficient emphasis has been put on understanding how these platoons affect the behaviour of other vehicles on the road; thus the possible drawbacks of this technology are not yet fully understood [6].