Clearing the Way - Preemption of Signalized Intersections

When: September 12, 2024, 2024 | 2:00 - 3:30 PM ET

This webinar is led by the ITE Traffic Engineering Council and Railroad Grade Crossing Committee.

Webinar Description:

This webinar will discuss the basics of the preemption of signalized intersections, with a focus on intersections near railroad grade crossings and the safe passage of emergency vehicles. After a brief discussion of signal preemption and how it compares to signal priority, we will provide an overview of railroad grade crossing preemption, including the necessary infrastructure for both the railroad and intersection signal systems, a discussion of the sequenced stages of the preemption routine, including their time constraints and requirements.

Next, we will review the basics of emergency vehicle preemption, including a review of the currently used technologies for preemption activation, a discussion of signal sequences (including the potential for the "yellow / left turn trap"), and timing considerations. The benefits and constraints of emergency vehicle preemption will also be discussed.

Finally, we will provide a discussion of the impacts of preemption on traffic flow. Considerations include road user delay, queue formation, and resynchronization into a coordinated timing pattern. We will discuss the concerns of truncating or omitting pedestrian intervals during the entry into preemption. A variety of exit strategies and how they can best be implemented will also be discussed.

Learning Objectives:

• Understand the difference between signal preemption and signal priority, and how each affects traffic flow.
• Recognize the importance of preemption at locations where railroad grade crossings and signalized intersections are in close proximity to each other.
• Describe the basic sequences of railroad grade crossing preemption, including right-of-way transfer, track clearance, dwell, and exit.
• Recall the various technologies related to emergency vehicle preemption.
• Understand the impacts of preemption on road users and the potential countermeasures to minimize those impacts.

Moderator: 

Peter Yauch, P.E., Vice President Emeritus | Iteris, Inc. | Tampa, FL, USA

Presenters:

• Karen Hankinson, P.E., Senior Team Leader / Rail | Olsson | Irvine, CA, USA
  David Champoux, P.E., Senior Signal Timing Engineer | CHA | Boynton Beach, FL, USA
  Steven Florko, P.Eng, Transportation Engineer | MORR Transportation Consulting Ltd. | Winnipeg, Manitoba, Canada