Construction that will reconfigure the four-lane stretch of Island Crest Way south of 42nd Street into three lanes is set to begin by the end of the month.
Many South end residents worry the changes will worsen congestion on the busy roadway during peak periods.
Engineers say that speeds will drop and safety will improve along the corridor.
Clint Morris, street engineer for the City of Mercer Island, said that recent road diet projects have been successful in other King County cities.
“Cities such as Seattle and Sammamish have seen the benefits of a three-lane configuration vs. a four-lane roadway,” he said.
“Three lanes help left turn movements, and pedestrian crossings are safer with the addition of ‘refuge islands’ within the roadway.
Design engineer Clinton Davis, of the engineering consulting firm KPG, agrees. He points to roadways that were changed from four to three lanes in Seattle that have become safer and handle just as much traffic.
The recently completed Nickerson Street road diet in Seattle is similar to what is planned for Island Crest Way. The average daily traffic count (ADT) for Nickerson is given as 18,500. The section of Island Crest Way getting the four to three-lane reconfiguration this summer has an ADT range of 18,000 to 20,000.
In August 2010, a stretch of Nickerson Street from 13th Avenue to the Fremont Bridge was changed from four lanes to three, to make it safer for bicyclists, pedestrians and drivers. A new bike lane was added and two more crosswalks were painted.
As a result, traffic collisions dropped nearly a quarter last year compared to the prior five-year average, according to a story in the Seattle PI. Drivers have slowed down. The average speeds on the stretch are now 33 mph, down from 42 mph, according to Seattle Department of Transportation data. The posted limit is 30 mph.
Perhaps more important to drivers who depend on the arterial to get around; the traffic volumes on the roadway have remained the same after the change.
“We are hoping to achieve similar results on Island Crest Way as Seattle has seen with Nickerson Street,” said Morris of the city.
When the $241,000 project was first announced by then-mayor Greg Nickels, it met resistance from business, freight and interests over concerns about losing a lane of traffic.
Nickerson Street was just one of 36 recent road diet projects in Seattle on a major arterial.
“I drive this every day to work and haven’t observed any increased congestion or delay in my commute,” Davis said.
The contract for the work was awarded to Lakeside Industries of Issaquah, which has worked for the city on prior paving projects. The contract with Lakeside is for $1,244,862. The total project budget is $1,653,797.
Repaving should be completed by mid-August, with the entire project scheduled for completion by Labor Day and the first day of school.
