Connected and Automated Vehicles on a freeway scenario. Effect on traffic congestion and network capacity

Abstract

In the next decades, road transport will undergo a deep transformation with the advent of Connected and
Automated Vehicles (CAVs), which are about to drastically change the way we commute. CAVs promise to
increase productivity and comfort and to facilitate a greater inclusion in mobility of specific user groups, which
may eventually lead to increased travel demand. Together, CAVs will enable the full potential of self-driving
technology and they will completely merge over time. The complexity of transportation systems is high and
therefore, efficient tools for the assessment of this disruptive change are important.
The objective of this paper is to evaluate the behavior of automation and/or connectivity in vehicles under realistic
traffic conditions and provide preliminary indicative results aiming to assess the efficiency of the corresponding
technologies in terms of traffic congestions and network capacity. In the present work, the case-study of the ring
road of Antwerp was used along with traffic demand generated based on real traffic counts.
Preliminary results show that, ceteris paribus, automation alone is less probable to have positive impacts on traffic
conditions. The safety constraints that AVs will be designed to fulfill are in fact likely to generate vehicle which
are as cautious (if not more cautious), than human drivers. In this picture, the significant step ahead can be brought
by connectivity. Vehicles able to communicate in a seamless and secure way can theoretically see an effective
reduction in time headways and reaction time with a consequent positive effect on network capacity and thus road
congestion until the traffic demand stays constant. This effect is made more evident as their penetration rate over
the entire network increases.
Preliminary results presented in this paper seem to confirm the effectiveness of the strategy put forward by the
European Commission to consider connectivity, cooperation and automation as deeply intertwined aspects of the
future transformation in the transportation sector.