Alternative Intersection Treatments
Credits: 2 PDH
PDH Course Description:
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.
Topics:
- Reconfiguration: removal of intersection skew angle
- Reconfiguration: removal of deflection in travel path for through vehicles
- Reconfiguration: conversion of four-leg intersection to two T-intersections
- Reconfiguration: conversion of two T-intersections to four-leg intersection
- Reconfiguration: closure of intersection leg
- Indirect left turn treatment: jughandle
- Indirect left turn treatment: median U-turn crossover
- Indirect left turn treatment: continuous flow intersection
- Indirect left turn treatment: quadrant roadway intersection
- Indirect left turn treatment: super-street median crossover
- Grade separation treatment: split intersection
- Grade separation treatment: diamond interchange
To take this course:
1.) Enroll in Course: Click below to enroll:
(must be logged into your user account)
Download the Study Guide
3.) Test: Once you've thoroughly read the course materials, please click below to take the final examination.
Take the final exam
4.) Certificate: A passing grade of 70% or higher on the exam, is required to receive the certificate of completion for this PDH course.
NOTE: After the exam is completed, you will need to return to this page, in order to print (download) the certificate of completion.
Print the Certificate of Completion
Intended Audience: This course is intended for highway engineers, planners, and decision-makers involved with the planning, design, and operation of high-volume, signalized intersections.
Publication Source: US FHWA
Print the Certificate of Completion
Intended Audience: This course is intended for highway engineers, planners, and decision-makers involved with the planning, design, and operation of high-volume, signalized intersections.
Publication Source: US FHWA
Mark Rossow PhD, PE (retired)