The bicycle portion of the race will affect traffic patterns on May 11

Traffic Patterns

Traffic patterns — The bicycle portion of the IRONMAN Santa Rosa will affect traffic and travel throughout the north county on May 11. 

On May 11, the bicycle portion of the IRONMAN Santa Rosa triathlon will wind its way through the north county, including significant portions of Windsor. Traffic patterns will be affected, due to either road closures, or having to share the roads with racers. The effects will be felt approximately 9 a.m. to 4:30 p.m. on race day.

The swim portion of the race will take place at Lake Sonoma, while the bike portion will wind its way through north county. They will leave Lake Sonoma via Rockpile, Dry Creek and then Dutcher Creek roads, before turning around at Santana Drive and heading down Asti Road to Highway 128. They’ll travel Highway 128 to Chalk Hill Road, before heading down Faught Road to Shiloh Road and then across to Westside Road and then Dry Creek Road to meet back up with the first loop at Canyon Road and Highway 128.

They will then go down 128 to Chalk Hill Road to Shiloh Road again, before turning south on Windsor Road to take Slusser Road to Olivet Road, to West College Avenue to Stony Point Road, where the transition to the final running phase will take place.

The race finishes up in Railroad Square off of 4th Street in Santa Rosa. The swim portion will be 2.4 miles, the bike course is 112 miles, and the final run is 26.2 miles, a marathon.

For the swim portion, racers have two hours and 20 minutes to complete the swim without being disqualified, and the start will be staggered by groups. For the bike portion, racers must be dismounted from their bikes by 5:30 p.m. to be allowed to continue. The race closes at midnight. In 2018, over 1,600 people competed.

In Windsor, traffic control equipment will begin getting installed around 7:30 a.m. and Windsor Police will be managing athletes and vehicles at Old Redwood Highway and Shiloh Road; Skylane Boulevard and Shiloh Road; and Windsor Road and Shiloh Road. There will be road closures and delays along this route. Eastbound Shiloh Road will be closed from Caletti Avenue to Hembree Lane. No access to the east side of Highway 101 will be allowed, all eastbound traffic will be forced onto Highway 101 South.

All businesses off of Shiloh Road and Hembree Lane will be open throughout the day.

Fans who want to follow the progression of the race can check out IRONMAN now on Facebook,, or download and athlete tracker app at

The IRONMAN Santa Rosa will offer 40 qualifying spots for the 2019 IRONMAN World Championship in Kailua-Kona, Hawaii, on Oct. 12. The slots are allocated according to the sizes of the event’s age groups and by placement of athletes within those groups. Nationwide there are 41 qualifying events, and over 2,500 athletes will compete in Hawaii.

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