Interchange Improvement Project

The Interchange Improvement Project on Interstate 5 at Exit 16 (NW La Center Road)

The Interchange Improvement Project, part of the Cowlitz Project, is a $32 million private investment to overhaul and upgrade the interchange at Exit 16.

Located along I-5, the interchange at Exit 16 serves the City of La Center and surrounding rural areas. While the interchange supports current needs, planned development on both sides of the freeway is projected to result in growth and increased traffic.

To continue providing safe and efficient access to and from I-5, the existing interchange at Exit 16 must be modified. The construction process is anticipated to be completed in June 2017.

Specific needs at the interchange that will be addressed by this project include:

  • Deficient access spacing per WSDOT standards
  • Anticipated failing operations with future growth
  • Substandard bridge in terms of lane-widths, shoulders, pedestrian facilities, and seismic standards

The Cowlitz Tribe has worked closely with the Washington State Department of Transportation (WSDOT), the Federal Highway Administration (FHWA), the City of La Center and Clark County to ensure that the new roads meet all necessary state and federal regulations.

Notice of I-5 Construction at Exit 16

Construction has begun on the Exit 16 interchange (at NW La Center Road and NW 319th Street).

Project Area

The project is located on a stretch of I-5 less than a mile in length, between milepost 16.10 and 16.94. The NW La Center Road interchange is located at milepost 16.80 and includes a narrow two-lane overpass built in 1969.

The scope of work includes widening NW La Center Road; realigning NW Paradise Park Road, NW 31st Avenue; and NW 319th Street; and reconfiguring the ramp terminal intersections to roundabouts.

Upon completion in 2017, the area will feature:

  • A new overpass accommodating four motor vehicle travel lanes, pedestrians and bicycles.
  • Multilane roundabouts for existing northbound and southbound interchange ramp terminals.
  • A lengthened northbound off-ramp that will have two exit lanes from I-5.
  • A two-lane southbound on-ramp that transitions to a single lane prior to the I-5 merge.
  • A partial relocation of NW Paradise Park Road, creating a new intersection with NW La Center Road. The initial stop-control for traffic flow will eventually be converted to a traffic signal.
  • Relocation of NW 319th Street (referred to as Cowlitz Way) to accommodate the new overpass and provide an enhanced east-west circulation network that is more compatible with the Cowlitz Reservation Development.
  • A partial relocation of NW 31st Avenue and the development of a new intersection with Cowlitz Way operating as a roundabout.

La Center Road Water Line Implementation

October 25, 2016 - mid- December

Construction is underway in La Center, Washington to install a new main line that will provide municipal water to eastern La Center and the Cowlitz reservation. The Project is part of the Cowlitz Interchange Improvement Project, a $32 million investment improving roads and resources across the La Center and Ridgefield communities.

The team has begun installing the new water main beginning at the intersection of La Center Road and Timmons Road in La Center, WA. The total length of the line is 5,500 feet with crews installing approximately 200 feet per day. The project is expected to be complete by mid-December.

To complete the construction of the new water line and ensure the safety of the entire community, 300 foot spans of La Center Road will be restricted to one lane of traffic, Monday through Saturday from 7:00 a.m. through 6:00 p.m. La Center Road will remain open during construction with both lanes open in all non-working hours.

We kindly request travelers and commuters taking La Center road both directions during this time schedule a little extra travel time for the lane closures. The project team currently estimates traffic delays between 3-6 minutes with delays not to exceed 15 minutes.

Thank you for helping us keep a safe work zone.

Project Stages and Phases

To minimize out-of-direction travel for commuters, the project will be conducted in several stages with minimal disruption during peak travel hours.

  • Stage I: Phase 1 – August through early October
    Daytime traffic is not impacted. Expect overnight closures of the I-5 fast lane as the project gets underway with shoulder work and truck access to the median. At the end of this phase, during night time hours, I-5 traffic will detour along the off- and on-ramps to provide a single lane in each direction to place bridge elements.
  • Stage I: Phase 2 – early October to early November
    Daytime traffic lanes of I-5 will be shifted to the inside shoulders, and temporary striping will direct traffic flow. Overnight closures of the fast lane will continue. The temporary northbound loop off-ramp and southbound loop on-ramp will be put in use, and frontage road traffic will shift.
  • Stage I: Phase 3 – November through early 2017

Later Stages (Dates will be added as the project progresses):

  • Stage II - November 8, 2016 to mid-May 2017
    Beginning November 8th all access points to I-5 north and south from Exit 16 will be rerouted to temporary on and off ramps. Traffic traveling north - bound on I-5 will now shift to the temporary NW La Center Road northbound loop off-ramp. Travelers entering I-5 south from La Center Road will now use the southbound loop on-ramp. Daytime traffic lanes of I-5 will continue to travel over the inside shoulders. Frontage road traffic maintains shifted as outlined in Stage I, and the temporary northbound on-ramp and southbound off-ramp remain in use.
  • Stage III
    This stage initiates new travel patterns and is a transition stage to the ultimate configuration.
  • Stage IV
    Traffic continues to move in the new travel pattern, with the addition of a shift to the permanent southbound off-ramp and northbound on-ramp. During night time, I-5 traffic will be detoured along off- and on-ramps for a short period as demolition work of the existing I-5 bridge requires closure of all lanes.

Traffic Impacts

Current plans call for construction to be completed in four main stages. Each stage – and any associated phases – will likely impact traffic movement. The goal is to maintain existing lane configurations throughout the construction period. Most ramps will remain open for the duration.

Every effort will be made to minimize lane and ramp closures on I-5 during the high traffic volume daytime hours, limiting lane and ramp closures to night times and/or weekends to the greatest extent possible.

Work Zones and Lane Closures

Where space permits, long-term work zones will be created and protected with a concrete barrier, and motorists should note entrances into these work zones and watch for construction vehicles proceeding through.

Some sections of the roadway cannot be protected using a barrier, such as along the shoulder. Shoulder closures and even lane closures may be required for activities in such areas; in the event of lane closures, care will be taken to create short- or intermediate-term impacts at most.

Portions of I-5 in both directions will be shifted towards the median for the construction of the dual northbound off-ramp and the southbound on-ramp to create space for construction workers. These traffic reconfigurations will be long-term and will be marked with temporary striping.

Work Zones and Flaggers

Intersections on NW 319th Street, NW La Center Road, and/or NW Paradise Park Road may be flagged if needed to help traffic pass through the respective intersections.

Furthermore, alternating one-way, flagger-controlled traffic may be used during construction operations on NW 31st Avenue, NW 319th Street, NW La Center Road, and/or NW Paradise Park Road, and during various work activities.

Work Zones and Pedestrians

The temporary alignment (series of S-curves) of NW La Center Road through the construction area will continue to accommodate pedestrians and cyclists similar to existing conditions. The temporary realignment of NW La Center Road through the construction area will continue to retain 3-foot shoulders to accommodate foot traffic.

Day Time vs. Night Time Hours

Temporary lane closures or ramp closures are planned to occur during the off-peak or night time to avoid excessive congestion. For the purpose of this project and for drivers planning to travel through the area, night time and off-peak hours are considered as:

The closure of one lane on weekdays may occur:

  • 7:00 PM to 6:00 AM daily, Monday evening through Friday morning

The closure of one lane on weekends may occur:

  • 8:00 PM to 10:00 AM, Friday evening to Saturday morning
  • 7:00 PM to 10:00 AM, Saturday evening to Sunday morning
  • 8:00 PM to 6:00 AM, Sunday evening to Monday morning

The closure of two lanes on weekdays may occur:

  • 9:00 PM to 5:00 AM daily, Monday evening through Friday morning

The closure of two lanes on weekends may occur:

  • 11:00 PM to 7:00 AM, Friday evening to Saturday morning
  • 10:00 PM to 8:00 AM, Saturday evening to Sunday morning
  • 10:00 PM to 5:00 AM, Sunday evening to Monday morning

Full closure of I-5 northbound and southbound may occur:

  • 11:00 PM to 4:00 AM daily, Monday evening through Friday morning

NW 319th Street/NW La Center Road will have no lane closures:

  • 6:00 AM to 9:00 AM daily, Monday through Friday
  • 4:00 PM to 6:00 PM daily, Monday through Friday

No lane closures will be allowed on a holiday or holiday weekend, after 12:00 PM (Noon) on a day prior to a holiday or holiday weekend, or before 9:00 AM on the day after the holiday or holiday weekend.

Traffic Monitoring

Throughout the construction project, traffic control measures and their impact on traffic flow will be monitored for problems, and actions will be taken to remedy any unexpected difficulties.

Know Before You Go…

To ease travel through the area, allow for extra time to reach your destination. Before heading out, check for project updates, detours and road closures online at http://www.wsdot.com/traffic/trafficalerts/SouthWest.aspx

Follow the Washington State Department of Transportation on Twitter (@wsdot_sw) for traffic conditions and updates.

Tune into KEX 1190 AM for up-to-date highway advisories.

For Cyclists

A bike detour is available for cyclists in the area. Due to narrowed lanes and minimal should width along I-5 through the construction zone, cyclists are encouraged to use the detour in the interest of safety and traffic movement. The detour will be along NW 31st Avenue between the I-5Ridgefield and the I-5 NW La Center Road interchanges. Maps will be posted in flyer boxes at exist points.

Open for Business

All local businesses will remain open and accessible throughout the construction project. All access sidewalks and driveways, as well as routes for pedestrians and motor vehicles to get to them, will be available during business hours.


Any inquiries related to the Interchange Improvement Project should be directed to:
Kim Stube, Director of Transportation, Cowlitz Tribe
(360) 353-9428, kstube@cowltiz.org