Compared to unsignalized intersections, signalized intersections increase capacity, reduce right-angle crashes, and permit vehicles, pedestrians, and bicyclists from minor volume approaches to safely cross an intersection. However, they create off-peak delay to minor approaches, increase frequency of rear-end crashes, increase congestion, and have high maintenance costs. TMUTCD signal warrants are recommended to be met before an intersection is converted into a signalized intersection. Signalized intersections are comprised of the following subcategories: isolated, coordinated, and clustered.