The latter shows the number and type of conflicts that occur at intersections with three and four legs, respectively.
The number of potential conflicts for all users increases substantially at intersections with more than four legs.
Avoiding these undesirable effects can improve both the safety and capacity at an intersection. An effective intersection design promotes desirable speeds to optimize intersection safety.
Figure 11 shows how pavement markings can be applied to delineate travel paths. The appropriate speed will vary based on the use, type, and location of the intersection.
Providing exclusive left-turn bays that can accommodate left-turn movements can improve operations and safety while providing flexibility to accommodate varying traffic patterns.
The needs of all possible road users (see chapter 2) must be considered to achieve optimal safety and operational levels at an intersection.At times, design objectives may conflict between road user groups; the practitioner must carefully examine the needs of each user, identify the tradeoffs associated with each element of geometric design, and make decisions with all road user groups in mind.This chapter addresses the following topics: a primary goal of intersection design is to limit or reduce the severity of potential road user conflicts. The approach alignment to an intersection as well as the intersection itself should present the roadway user with a clear definition of the proper vehicle path.Speed differentials at intersections are inherent as vehicles decelerate to facilitate a turning maneuver.The provision of exclusive left- and right-turn lanes can improve safety by removing slower moving turning vehicles from the higher speed through traffic stream and reducing potential rear-end conflicts.