Operation Regimes and Slower-is-Faster-Effect in the Control of Traffic Intersections

Abstract

Abstract. The efficiency of traffic flows in urban areas is known to crucially depend on signal operation. Here, elements of signal control are discussed, based on the minimization of overall travel times or vehicle queues. Interestingly, we find different operation regimes, some of which involve a "slower-is-faster effect", where a delayed switching reduces the average travel times. These operation regimes characterize different ways of organizing traffic flows in urban road networks. Besides the optimize-one-phase approach, we discuss the procedure and advantages of optimizing multiple phases as well. To improve the service of vehicle platoons and support the self-organization of "green waves", it is proposed to consider the price of stopping newly arriving vehicles.

Perimeter and boundary flow control in multi-reservoir heterogeneous networks

“…However, these temporary queues in FPC and BBC is proved beneficial for the total network throughput. 6 Thus, even if vehicles are restricted in the perimeter of the network, they are able to reach their destinations faster than in the no control case (''slower is faster'' effect, see Helbing and Mazloumian, 2009). Finally, the significantly lower number of vehicles within the network links (Vehicles Waiting Out) at the end of simulation indicates that the FPC control action does not create queues that spill back to upstream intersections at the boundary of neighborhood reservoirs.…”

Platoon-based self-scheduling for real-time traffic signal control

“…The advantage of PBSS over AAC also provides a demonstration on the slower-is-faster effect [7], a counterintuitive, but practically relevant effect in many queuing systems. A study on uniform arrival flows [7] suggests one possible reason for this effect, i.e., a road with a small utilization might wait to have enough vehicles in order to balance the efficiency loss caused by switching lights.…”

“…A study on uniform arrival flows [7] suggests one possible reason for this effect, i.e., a road with a small utilization might wait to have enough vehicles in order to balance the efficiency loss caused by switching lights. Our work is based on non-uniform arrival flows, which is more realistic.…”

“…More recently, a self-control method was proposed based on the notion of an "anticipated queue", which contains not only those vehicles already queued at the intersection, but also those predicted to reach the intersection before the last queued vehicle is cleared [8]. Our method incorporates this idea, but the focus shifts from minimizing queues [7], [8] to maintaining movement of vehicle platoons.…”

“…Long queues and platoons satisfy this requirement. Minimization of vehicle queues [3], [7] is a straightforward means for achieving green waves, since a zero queue means an ideal optimization. However, clearing all existing queues will not necessarily lead to this optimal result, since queues certainly impose delays and the presence of small queues can lead to excessive switching costs.…”