OLYMPIA, Wash. - Transportation officials in Oregon and Washington have a message for the region's drivers: However bad you think traffic is going to be during next Monday's total solar eclipse, it's probably going to be worse than you imagine. A lot worse.

"Waking up early to leave the Seattle area to head south the morning of the eclipse is not a good idea," WSDOT southwest region communications manager Bart Treece wrote in a blog post. \

RELATED: Are you eclipse glasses safe?

PODCAST: Watching total eclipse felt like 'armageddon' was coming

The Oregon Department of Transportation expects the eclipse to be the biggest traffic event in the state’s history drawing about 1 million people to the zone of totality to view the event.

The zone of totality stretches from Salem at 10:18 a.m. to Madras at 10:21 a.m. to Baker City at 10:25 a.m.

While just a 60-to-70 mile wide swath of central Oregon is within the path of totality, Washington and Oregon officials say that significant backups are expected throughout both states both before and after the short event ends, with potentially hundreds of thousands of people clogging the roadways as they try to drive home or head to airports.

WSDOT says a typical morning commute between Vancouver, Wash., into Portland backs up for miles. The eclipse will add thousands of cars to that just on Interstate 5.

Avoid sitting in traffic

"The word from our friends at the Oregon Department of Transportation for folks making the trip is to 'Arrive Early, Stay Put and Leave Late,'" Treece wrote.

Vancouver, Wash. hotels are sold out on Sunday night, but they’re also 80 percent booked on Monday night, suggesting many people will stay past the eclipse, according to Treece.

Resources: Traffic App | Oregon road maps | Oregon TripCheck travel info | Traffic alerts

WSDOT expects major thoroughfares into Oregon will be slow going, including the following highways:

*Interstate 5 – Vancouver to Eugene
*Interstate 82 – Benton County
*US 97 – Klickitat County
*State Route 14 – Columbia River Gorge
*US 197 – Dallesport
*Interstate 205 – Clark County to Portland
*State Route 433 – The Lewis and Clark Bridge in Longview
*State Route 4 – Longview to Naselle
*State Route 401 – Naselle to Dismal Nitch
*US 101 – Ilwaco to Astoria

Oregon does not anticipate closing any state highways, but they may restrict left turns to keep traffic moving.

The eclipse is the first coast-to-coast total solar eclipse in the United States since 1918, and the first to hit any section of the U.S. mainland since 1979.

Eclipse road trip tips

Don’t wear eclipse glasses while driving. If the glasses do what they’re supposed to, you won’t be able to see anything but the sun.

Don't try driving and looking at the eclipse. This should go without saying, but you know someone will try it.

Don’t camp out at rest stops. Rest areas are designated for travelers who are not staying longer than eight hours.

Don’t park your car on the shoulder. If you want to pull off the highway to watch the eclipse, don’t use the shoulder. It may be needed for emergency vehicles to get through. Heat from your car could also start a brush fire.

Make sure your car is in good working order. Also have enough supplies for a few days in case you get stranded.

Drew Mikkelsen and The Associated Press contributed to this report.

Related content

Complete KING 5 eclipse coverage

Download the KING 5 App

Download the Seattle Traffic App

Eclipse forecast