Enhanced Community Values & Other Community Benefits
While each location has specific needs and opportunities, the modern roundabout in certain locations have been used to provide traffic-calming effects, and mark community gateways with enhanced aesthetic opportunities.
Roundabouts can also be used to help control excessive vehicle speeds (also known as Traffic Calming): Enforcement of vehicle speeds in residential streets is not cost effective using already stretched police forces. A series of roundabouts will provide effective speed control along residential streets by physically reducing all vehicle speeds.
Traffic signals are a substantial liability for the operating authority. Attorneys often try to prove traffic signals were faulty and therefore the cause of their client's crash. In other words, drivers are not responsible for their behavior because "the traffic signals cause crashes." At a well-designed roundabout, liability for entry collisions rests with the entering driver: the driver failed to yield to the circulating vehicle.
In the other common type of collision, the rear-end, the following driver is at fault for following too closely. At a multi-lane roundabout a merge type crash responsibility rests with the driver who incorrectly changed lanes.
One main advantage of modern roundabouts is their considerable geometric flexibility. This enables the efficient connection of difficult roadway alignments.
This geometric flexibility is possible due to the slow approach, entering and exit speeds inherent in properly designed modern roundabouts. Conventional signalized intersections do not have such geometric flexibility as higher vehicle speeds require larger centerline radii.