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I-5, SR 510 to SR 512 – ITS & Ramp Revisions

UPDATE: Ramp Meters between SR 510 and SR 512 are expected to be activated as early as May 18, 2015. A list of ramp meter locations and an explanation of how they work is located here (pdf 144kb).

This project is one of several that WSDOT has undertaken to improve traffic flow on Interstate 5 in Thurston and Pierce counties.

In this project, WSDOT will install "intelligent transportation systems (ITS)" devices that help WSDOT manage traffic and communicate real-time traffic conditions to the public. Devices to be installed include:

  • 2 ramp meters
  • 2 closed-circuit traffic cameras
  • 1 variable message sign and supporting electronic hardware

This project also widens the Mounts Road Gate access road on Joint Base Lewis-McChord (JBLM) from one lane to two lanes. The widened access road will complement work completed by WSDOT and Pierce County in 2013 that installed turn lanes and a new traffic signal at the interchange of Nisqually Road SW and the JBLM Mounts Road Gate near Interstate 5.


See the Olympic Region Weekly Construction and Traffic Update report for current impacts to traffic.

Revised I-5 Center Drive Interchange
This project will also revise the I-5 Center Drive interchange, allowing for continued use from Joint Base Lewis-McChord.

Why is WSDOT revising the I-5 Center Drive Interchange, adding “smart highway” devices on I-5 near Carpenter Road, revising I-5 ramp meters in Nisqually and widening the Mounts Road Gate access road?

The current connecting road from Joint Base Lewis-McChord to Center Drive was originally built as an emergency access and was not intended for routine use. To allow the continued use of this road, the I-5 Center Drive interchange must be revised. Once completed, drivers using the Center Drive on-ramp to northbound I-5 will take a free moving left turn without stopping. A new HOV bypass lane and ramp meter will also be installed on the ramp. JBLM personnel will still be allowed to exit the base at Center Drive, where a new stop sign will be installed to provide traffic control. The northbound I-5 exit to Center Drive will not be altered.

During construction, motorist can expect one weekend closure of the northbound on-ramp, and possible night time closures as needed.

I-5 Center Drive Interchange Revision map

View full size image (pdf 220kb)

To help address increasing traffic volumes and longer hours of congestion seen along this I-5 corridor, WSDOT is installing fiber optic cable that will operate two traffic cameras and a variable message sign near Carpenter Road in Lacey.

To address traffic backups during peak hours on Martin Way East at I-5 in Nisqually, WSDOT will reconfigure the ramp meter, allowing for two metered lanes instead of one.
Improvements to the access road at the Mounts Road Gate located on JBLM intersection project is part of a series of projects being undertaken by WSDOT to reduce congestion on Interstate 5 during peak commute hours. By using this gate, JBLM traffic destined for Yelm or portions of Lacey can avoid using Interstate 5 by using this gate to enter and exit JBLM.

View the I-5 JBLM Area Improvements - Project Map for a complete look at I-5 corridor improvements in Thurston and Pierce counties.

Project Benefits

The I-5 Center Drive ramp revision will allow JBLM personnel to continue to exit the base at Center Drive.
The cameras and ramp meters allow WSDOT to manage traffic demand. From a central traffic management center, WSDOT staff use the camera images to keep apprised of traffic conditions on state highways.

The images are used to call out emergency personnel, report traffic conditions through highway signs and radio messages, and monitor traffic flow. They are the same images you can use to know before you go.

Ramp meters manage traffic demand by controlling the number of cars that merge onto I-5 when congestion is heavy. This will help keep mainline I-5 moving.

The new technology will also allow WSDOT to offer travel times from Olympia to Tacoma.

The widened access road at the Mounts Road Gate will accommodate two-way directional traffic.

What is the project timeline?

Construction is expected to start in June 2014, and be completed late-summer of 2014. Construction is weather dependent.

Financial Information

               Financial Data for PIN 300596T - WIN C00596W
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $0
Pre-Existing Funds (PEF) $353
Tiger III - Federal Funds $2,147
Total $2,500

How can I get more information?

Kim Mueller, P.E. 
WSDOT Project Engineer
Claudia Bingham Baker
WSDOT Communications Manager