Control Algorithm, Safety and Traffic Impact Analysis of Automated Variable Speed Limit

Author(s): Bidoura Khondaker, Lina Kattan
Student Paper Competition: 3rd Place

Slidedeck Presentation:

Student Comp - KHONDAKER_Control algorithm safety and traffic impact analysis of automated variable speed limit


This paper presents evaluation of a model based Variable Speed Limit (VSL) control algorithm
for maximizing the mobility and safety of traffic network. A Model Predictive Control (MPC)
approach is used with traffic prediction and performance evaluation capabilities. Improvement
of the network efficiency has been measured in terms of minimizing Total Time Spent (TTS) of
all the vehicles in the network. A simulation-based surrogate safety measure Time To Collision
(TTC) has been used to capture the probability of collisions between two pair of vehicles. A
multi-criterion objective function has been formulated having Total Time Spent (TTS) as network
efficiency measure and Time To Collision (TTC) as the instantaneous safety measure. In order
to create an active bottleneck, an artificial collision was created resulting in queue formation
upstream of the bottleneck. VSL trigger condition was based on a 'speed drop' algorithm. The
performance of the presented VSL algorithm has been tested using Microsimulation tool
VISSIM. Genetic Algorithm is used to calculate the optimized control values by developing a
integrated VISSIM COM-MATLAB interface. The findings from the paper suggest that the
application of VSL can substantially contribute to improved traffic flow and a more
homogeneous traffic situation, which increases safety. The results of the experiments have
shown that the proposed approach which is based on driver behaviour can significantly improve
network safety condition while still improving travel time of vehicles.