Heading out for one last summer holiday weekend? Planning ahead could be the key to smooth sailing, whether on land or sea, the Washington State Department of Transportation says.

Travelers can use WSDOT’s traffic volume charts this holiday weekend to “know before they go” and help time their travel on key routes. In particular, this year, holiday congestion is expected on Interstate 90 near Snoqualmie Pass — especially westbound traffic.

I-90/Snoqualmie Pass

Bridge deck repairs in the westbound lanes of I-90 between the summit of Snoqualmie Pass (milepost 52) and North Bend (milepost 34) will not be complete by Labor Day as initially hoped. This means only two of three lanes will be open for drivers heading westbound. The lane closures are needed because portions of the bridge decks have been removed and traffic can’t be shifted back on those decks until new concrete is placed and cured. Drivers will also encounter lane closures and traffic shifts through the Cle Elum area (milepost 86) due to work to replace old pavement with new concrete lanes.

During the holiday weekend:

• Eastbound travelers will experience delays on Friday, Sept. 1, and should consider traveling early in the day or late in the evening.
• Westbound travelers should expect major delays Monday, Sept. 4, near the detour. If possible, travelers may want to leave early or possibly extend their return trip into Tuesday, Sept. 5.
• The WSDOT I-90 travel charts do not reflect this construction work, but they can still be used as an overall guide to the times when the most congestion is expected.

Advice for navigating congested areas

• Slow down: Please obey posted speed limits. Speed is reduced for everyone’s safety.
• Stay alert: Be especially aware of other vehicles and prepare for any sudden stops.
• Allow extra travel time: Drivers delayed by congestion sometimes try to compensate by driving faster once the congestion clears. Instead, allow extra travel time or consider adjusting travel schedules if possible.

Know before you go

• Check WSDOT’s mobile app, Twitter and Facebook accounts, and online tools for traffic information and ferry schedules.
• Call the 511 travel information hotline. For out-of-state callers, it’s 1-800-695-ROAD (7623).
• Pre-program vehicle radios to 530 AM and 1610 AM for highway advisory radio alerts.

To ease congestion statewide, WSDOT suspends most state highway construction work during the holiday weekend starting Friday, Sept. 1. On Labor Day, Monday, Sept. 4, the State Route 520 bridge toll will be on holiday rates, while the Interstate 405 express toll lanes will be free and open to all drivers.

Washington State Ferries passengers should expect heavier traffic during the holiday weekend and reservations are strongly recommended for the Anacortes/San Juan Islands; Anacortes/Sidney, British Columbia; and Port Townsend/Coupeville ferry routes.

• Reservations can be made onlineor by calling 888-808-7977.
• Visit the schedules and best travel timeswebsite for more details.

Note that most public transit systems will follow a holiday schedule, and some transit systems will not operate fixed-route or Dial-A-Ride service on holidays.