Travis Phelps, a spokesman for the state Department of Transportation, responds: At intersections between state routes and county roads we often place stop signs on the county legs while allowing highway traffic to travel freely through the intersection, since the highway traffic is usually the major movement. The free-flow movement for highway traffic is easily achieved when the highway itself is straight or has a modest curve.
The intersection of Highway 531 (172nd Street NE) and Forty Five Road, however, is atypical. Highway 531 forms a 45-degree angle at the intersection. Drivers on westbound Highway 531 are required to stop because of the unique geometry.
This angle limits our operational choices in two key ways. Highway traffic typically travels through an intersection at approximately the posted speed limit, whereas at Forty Five Road the safe turning speed during a westbound right turn is considerably lower than the 40 mph speed limit. The skewed intersection also means that views are quite limited between westbound Highway 531 traffic and northbound Forty Five Road traffic.
If required to stop, northbound traffic on Forty Five Road would have trouble seeing westbound Highway 531 traffic because of an awkward view-angle across a taller landscape with foliage. We determined that traffic flow through this intersection is best managed with the westbound highway traffic being stopped.
We analyzed the current setup in comparison to what drivers could expect from two other scenarios – placing a stop sign on Forty Five Road, and converting the intersection to an all-way stop.
The results showed little to no improvement with different stop-sign arrangements when compared to the existing configuration. Reconstructing the intersection to provide a better alignment for the highway would be costly and not compete well against other intersection needs.
Road closures coming
Direct access between U.S. 2 and Bickford Avenue near Snohomish will be closed for three nights this week while crews install a new drainage system under Bickford. The work is part of the state's $22 million project to install a new overpass and ramps to improve safety at the intersection.
Bickford Avenue at U.S. 2 will be closed from 7 p.m. to 5 a.m. each night Monday through Thursday. Nighttime drivers wishing to exit or enter U.S. 2 will have to go to the Highway 9 interchange about a mile east of Bickford.
Another, longer closure of Bickford access is planned for September. Afterward, the project, which includes new on- and offramps, is expected to be finished.
In Lake Stevens, a section of Highway 92 is scheduled to be closed to through traffic around the clock for five days beginning Sunday night for the installation of two roundabouts.
The highway will be closed from 99th Avenue NE to 113th Avenue NE from 7 p.m. Sunday to 8 a.m. Saturday. Crews working for the state Department of Transportation plan to install roundabouts at those two intersections.
During the closure, drivers will be detoured to 84th Street NE and Highway 9.
The project costs a combined $7.7 million for the two roundabouts. It's expected to improve safety on the highway, where a combined 42 accidents took place at the two intersections between 2006 and 2010, according to the state.
E-mail us at email@example.com. Please include your city of residence.
Look for updates on our Street Smarts blog at www.heraldnet.com/streetsmarts.
Most recent Street Smarts posts
Our new comment system is not supported in IE 7. Please upgrade your browser here.