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- Waiting Time Analysis for a Network of Signalized IntersectionsPublication . Reddy, Radha; Almeida, Luis; Santos, Pedro M.; Tovar, EduardoVehicle waiting time or stopped delay is one of the major disadvantages of employing signalized intersections (SIs) in road networks. The waiting time delays occur when vehicles stop in the queue, waiting to access the SI, and vary from road lane to road lane with the intersection management (IM) protocol used. In this research line, we propose an analytical expression for estimating the waiting time delays and studying the performance of different IM approaches in a grid network of independent intersections. We consider complex intersections with four legs and two lanes with two left-lane configurations, as well as five state-of-the-art IM approaches: two conventional -- Round-Robin (RR) and Trivial Traffic Light Control (TTLC); two adaptive -- Max-pressure Control Algorithm (MCA) and Websters Traffic Light Control (WTLC); and one reactive -- Synchronous Intersection Management Protocol (SIMP). The waiting time performance of these five IM approaches is compared using two simulation scenarios in the SUMO simulation framework. The simulation results validate the analytical study and show the advantages of employing SIMP, being the IM approach with the lowest waiting time delays.
- Complex Intersections with a Dedicated Road Lane per Crossing DirectionPublication . Reddy, Radha; Almeida, Luis; Santos, Pedro M.; Tovar, EduardoComplex intersections are often busier with a separate road lane per crossing direction, i.e., left, straight, and right. These intersections eliminate the diverging and merging conflicts; thus, vehicles only fall under crossing conflicts within intersections. However, the traditional way of serving vehicles from one road at a time increases traffic congestion and hinders performance. To address this issue, we extended the synchronous framework for complex intersections with a separate road lane per crossing direction, which was initially presented for single-lane and two-lane intersections in which roads are shared among vehicles with different crossing directions. We compare the performance of our synchronous framework against the traditional Round-Robin (RR) intersection management approach.
- Synchronous Management of Mixed Traffic at Signalized Intersections towards Sustainable Road TransportationPublication . Reddy, Radha; Almeida, Luis; Gutiérrez Gaitán, Miguel; M. Santos, Pedro; Tovar, EduardoIn urban road transportation, intersections are traffic bottlenecks with increased waiting delays and associated adverse effects. A recently proposed intelligent intersection management (IIM) approach, the Synchronous Intersection Management Protocol (SIMP), synchronizes the vehicles access to simple single-lane isolated intersections, outperforming competing approaches in various performance metrics. In this paper, we apply SIMP to multi-lane intersections, increasing significantly the applicability of the protocol while dealing with the additional complexity emerging from the multiple crossing conflicts. Using the SUMO simulator, we compare the performance of SIMP with two conventional (Round-Robin - RR and Trivial Traffic Light Control - TTLC) and two IIM approaches (Intelligent Traffic Light Control - ITLC and Q-learning based Traffic Light Control - QTLC) under continuous and interrupted upstream traffic flows scenarios in urban settings. The results using a maximum speed of 30km/h confirm the superiority of SIMP, improving traffic throughput (~14.4%) and reducing travel delays (~64.4%) and associated fuel consumption (~25.5%) when compared to the best of the other approaches.
- Energy savings and emissions reduction of BEVs at an isolated complex intersectionPublication . Reddy, Radha; Almeida, Luis; Santos, Pedro Miguel; Kurunathan, Harrison; Tovar, EduardoImproving urban dwellers quality of life requires mitigating traffic congestion, minimizing waiting delays, and reducing fuel wastage and associated toxic air pollutants. Battery-electric vehicles (BEVs) are envisioned as the best option, thanks to zero exhaust emissions and regenerative braking. BEVs can be human-driven or autonomous and will co-exist with internal combustion engine vehicles (ICEVs) for years. BEVs can help at complex intersections where traffic is saturated. However, their benefits can be reduced by poor intersection management (IM) strategies that coordinate mixed traffic configurations inefficiently. This paper studies energy savings and emissions reduction using BEVs mixed with human-driven ICEVs under eight relevant IM approaches. It shows that adding BEVs has impacts on throughput, energy consumption, waiting delays, and tail-pipe emissions that depend on the specific IM approach used. Thus, this study provides the information needed to support an optimal choice of IM approaches considering the emerging trend towards electrical mobility.