TRB Webinar: Guidelines for Ramp and Interchange Spacing

TRB conducted a web briefing or "webinar" on December 14, 2011 that addressed the findings of TRB’s National Cooperative Highway Research Program (NCHRP) Report 687: Guidelines for Ramp and Interchange Spacing. Contact Reggie Gillum at RGillum@nas.edu to request a recording of the webinar.

This webinar will explore design, operations, safety, and signing considerations that influence ramp and interchange spacing decisions, as covered in Report 687: Guidelines for Ramp and Interchange Spacing. Presenters will discuss how they assessed the impact of ramp spacing on traffic operations using simulation models of closely-spaced ramp pairs and developed safety performance models.  The team considered freeway and interchange planning, design, and operations principles and established ranges of spacing values for a variety of ramp sequencing scenarios.  Panelists will discuss how their research results led to developing a framework for considering ramp spacing needs on freeway facilities and evaluating trade-offs to support ramp and interchange spacing decisions.  Presenters will also discuss guidelines that offer standardized definitions measuring ramp and interchange spacing, which have varied in previous design guides.

Learning Objectives: After the webinar, attendees should be able to do the following:

• Understand the origins and limitations of current ramp and interchange spacing guidance in the AASHTO Green Book
• Evaluate design, operations, safety, and signing needs at the site of a new interchange or an interchange being rebuilt.
• Assess available ramp and/or interchange spacing based upon the factors identified in the previous bullet and determine the feasibility of constructing a new ramp or interchange.

Presenters:
Brian Ray, Kittelson & Associates, Inc.
Pete Jenior, Kittelson & Associates, Inc.
R.J. Porter, University of Utah

Moderated by Michael Ereti, City of Houston, TX

Webinar Outline:

Brian Ray’s presentation will explore:

• Project overview and historical background
• Geometric design criteria that influence ramp and interchange spacing

Pete Jenior’s presentation will explore:

• Traffic operations criteria that influence ramp and interchange spacing
• Traffic operations research conducted as part of this project

R. J. Porter’s presentation will explore:

• Safety criteria that influence ramp and interchange spacing
• The safety research conducted in this project

Brian Ray will wrap up the presentations by outlining new guidelines for ramp and interchange spacing.

Request the recorded webinar: There is no fee for employees of TRB sponsors who request a webinar recording. In addition to employees of TRB sponsor organizations, the following are eligible to receive a complimentary webinar recording:

• TRB and National Academies employees;
• Chairs of TRB standing committees, sections, or groups;
• CRP panel members who were involved with developing the report or project that is the subject of the webinar;
• Members of the media; and
• Congressional staff members.

Others must pay $39 to receive the recording. View our pricing page for details.

Questions? Contact Reggie Gillum at RGillum@nas.edu.

After registering you will receive a confirmation email containing information about joining the webinar.

This webinar was developed in October 2011. TRB has met the standards and requirements of the NCEES Registered Continuing Education Program (RCEP). Credit earned on completion of this program will be reported to RCEP by TRB. Certificates of Completion will be issued to individuals who register for and attend the entire webinar session. Complaints about registered providers may be sent to RCEP, PO Box 1686, Clemson, SC, 29633. Website: www.RCEP.net.