Safestreet incorporated the two traditional functions of collector streets: access to abutting property and traffic flow. To reconcile these two “antagonistic” functions, Safestreet put the emphasis on a road geometry that constrains speed. For the traffic levels involved, one starts with one lane in each direction, to which one adds, depending on need, turning lanes. The design speed must lead drivers to follow the target speed. At collector street intersections, roundabouts are the best solution.