Drivers, get ready for a mess on freeways and Seattle roads again Sunday. Multiple events and work projects will make getting around tough.

More than 18,000 runners will hit the pavement for the Seattle Rock 'n' Roll Marathon & 1/2 Marathon, which starts early Sunday at 6:30 a.m. For the first time, the marathon will NOT be using the I-90 (since WSDOT has closed the center lane); however, several streets throughout Seattle will be closed Saturday for the route.

Both races begin at Alaska Airlines Field at Husky Stadium, cross the Montlake Bridge, head through the Washington Park Aboretum and various neighborhoods along Lake Washington, and finish at CenturyLink Field in SODO. Download marathon and 1/2 marathon course map (pdf) and 5K course map (pdf).

Several road work projects and other special events are also expected to clog traffic in Tacoma, Issaquah, and on I-5 and I-90.

"This weekend is going to be the new norm for the summer," WSDOT spokesperson Tom Pierce said during a Wednesday news conference. "We've got major work on I-5 in Seatac and Tukwila. We've got major work on I-90 in Bellevue, Issaquah, and east of North Bend. We've even got some work on SR 513 on the Montlake Bridge."

"It's never great to get stuck in traffic, but if you know that it's coming, I find it makes it just a little bit more tolerable."

Road work projects and special events impacting Puget Sound traffic:

*Northbound I-5 in SeaTac and Kent: Starting at 8 p.m. Friday, June 16 until 5 a.m. Monday, northbound I-5 through Seatac and Kent will be reduced to two lanes for the first of five consecutive weekends as crews repave the interstate between SR 516 and the Southcenter area. Similar work in early June created a backup of 6 miles and up to an hour delay.

WSDOT will also close the SR 516 on-ramp to northbound I-5 and the South 200th Street on- and off-ramps throughout the weekend. Drivers are advised to take alternate routes like I-405 or state routes 99, 167 or 509. All roadwork projects are pending sufficient weather conditions.

*Eastbound I-90 in North Bend, Cle Elum and Easton. Rock blasting work resumes on I-90, which will reduce traffic lanes along several points on I-90. Drivers should brace for backups going eastbound on Friday and Saturday, westbound on Sunday. Drivers can avoid traffic congestion if they travel early in the morning and later in the evenings. More details.

* Montlake Bridge in Seattle. On Saturday, the inside lanes of SR 513/Montlake Boulevard on the Montlake Bridge will be closed from 5:30 to 11:30 a.m. as crews do maintenance work.

June 15-18, 2017: The Tacoma Festival of Sail is expected to draw as many as 50,000 people to the Thea Foss Waterway. The northbound lane of Dock Street between E. 15th St. and Schuster Parkway will be closed starting Wednesday, June 14 at 4 p.m.; it will reopen at 10 p.m. Sunday, June 18. S 15th St. will be closed between Pacific Ave. and S. Hood Street. See traffic impact map

Sunday, June 18: Issaquah Fenders on Front Street vintage car show. Classic and vintage cars will line the streets of downtown Issaquah. Drivers can use the Front Street Exit from I-90; however, East Lake Sammamish Parkway will be closed just north of I-90 until 5 a.m. Monday 5 a.m.