I-5 Variable Speed Limits and Lane Control, Washington State

Overview

The project covers a 7-mile long section of I-5 northbound in Seattle and was activated August 10, 2010.

  • 15 overhead gantries, spaced approximately ½ mile apart through the 7-mile project area.
  • Gantries display dynamic speed limits, lane closures, merge arrows, warning information and variable messages.
  • Speed adjustments are automated and based on measured changes from imbedded sensors.
  • Lane control changes are human-initiated, but software automates the process of updating the signage and messages.
  • Variable speed limits sign show a minimum of 40 mph, even if traffic is moving slower.
  • Project has potential to improve congestion and safety
Content Type
Case Studies & Lessons Learned
Issue Date
Tactical Element
Active Management and TSMO
TOM Chapters
24.1
View Related
Publishing Organization
SHRP2 Program
Objective
Available Tools
Prime Contractor
Kittelson & Associates
Document Downloads