E – 1620 Jughandles and Other Alternative Intersection Treatments

This online traffic engineering PDH course describes how congestion-related problems can be solved by using alternative methods, that is, methods that differ from the conventional approach of adding capacity to an intersection simply by adding lanes. The conventional approach has diminishing returns. For example, if the addition of a second-through lane adds 15 years to the life of the intersection before it reaches capacity, the addition of a third through-lane adds only 10 years, and a fourth-through lane adds only 6 years. Large intersections increase loss time due to longer clearance intervals, protected left turn phasing, longer pedestrian clearance times, greater imbalances in lane utilization, and potential queue blockages caused by the resulting longer cycle lengths. Each of these issues suggests the need to look for alternative treatments. This course describes reconstruction treatments for signalized intersections in three categories: intersection reconfiguration, at-grade indirect movements, and grade separation. Many of these treatments are commonplace; others have seen limited or regional use. The common element in each treatment is the reduction in conflict points at the intersection, which provides safety and operational benefits by reducing the number of phases and conflicting volume at a single location.

This course is based on Ch. 10 of Report No. FHWA-HRT-04-091 “Signalized Intersections: Informational Guide,” written by Lee A. Rodegerdts, et al, August, 2004, and sponsored by the Federal Highway Administration under Contract No. DTFH61-98-C-00075, Task Order No. B98C75-009.