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
Operations Area of Practice
- Active Traffic Management (ATM)
Organizational Capability Element
- Active Traffic Management/Travel Demand Management/Pricing
- Case Studies & Lessons Learned
- SHRP2 Program
- Available Tools
i5_variable_speed_limits.pdf (179.02 KB)