An emissions-based user equilibrium model and algorithm for left-turn prohibition planning

The left-turn of vehicles at intersections has significant impacts on urban traffic congestions and accidents, which have negative effect on vehicle emissions causing air pollution. Many urban traffic networks prohibit direct left-turns for transport planning to keep traffic moving efficiently on major roads. As such, this paper proposes a bi-level mathematical model for left-turn prohibition planning considering both travel times and traffic emissions. The lower-level and upper-level are respectively solved by using the Frank-Wolfe algorithm and an improved genetic algorithm. By numerical examples, this paper shows that the improved algorithm can effectively enhance the speed and accuracy of the calculation, and the traffic congestions and emissions can be alleviated by implementing the left-turn prohibition at some carefully selected intersections.