GTS provided support to the Royal Commission of Riyadh City in evaluating the viability of alternatives to traffic signals for intersection control, looking at roundabouts and other solutions. The assessment included a benchmarking analysis of cities worldwide that had replaced traffic signals with other forms of control, examining factors such as vehicle speeds, pedestrian wait times, life cycle costs, safety, and multi-modal efficiency. GTS utilized the Riyadh Travel Forecasting Model to strategically illustrate the impacts of traffic signal removals across the city.

In the course of this study, GTS identified several opportunities and challenges. Some of the opportunities include the possibility of using emerging technologies (AI, virtual traffic lights) to enhance signal operations. More traditional opportunities include grade separation and removal of unnecessary signals. Challenges include the mixing of multimodal traffic (pedestrians and other non-vehicular modes) and the associated safety concerns, as well as the lack of uniformity in the roadway network. Our recommendations included the consideration of signal removal on a case-by-case basis; the implementation of new technologies, as they emerge, for signal optimization; the testing of virtual traffic lights as a new technology that makes use of vehicle-to-vehicle communication; and the use of grade separations to enhance mobility and livability by completely separating the different directions of traffic at certain junctions.

Because traditional signalized intersections have more potential conflict points compared to other solutions, and because Riyadh has a relatively low number of signalized intersections compared to benchmarked cities, this project presents a unique opportunity to improve safety proactively at a large scale. It is our hope that this feasibility assessment will lead to safer roads and more efficient traffic flow throughout the City.