By Bill Sheets Herald Writer
Sue Sullivan of Snohomish writes: Have you seen the plans for the Bickford Avenue-U.S. 2 overpass? After hearing about the state taking out the weaves to make Highway 18 safer to enter on I-5 in Federal Way, I cannot believe they would even consider this flyover-ramp design for the Bickford overpass. The state never contacted anyone about this (city of Snohomish, fire district, neighbors) to get preliminary input.
Bronlea Mishler, a spokeswoman for the state Department of Transportation, responds: The Bickford Avenue intersection on U.S. 2 is the last unsignalized, street-level intersection between I-5 and Highway 9 — basically, that means drivers don’t have an overpass or underpass (or traffic light) that allows them to safely merge on to U.S. 2 from Bickford Avenue. Instead, drivers have to turn left across two lanes of high-speed eastbound traffic to head west, or merge into high-speed eastbound traffic with limited room to get up to speed. The new overpass will eliminate the need for drivers to turn across traffic and will help reduce congestion and the potential for serious collisions. Work on the $19.7 million project is scheduled to begin this summer and conclude in the fall of 2013.
As part of our design process, we met with staff from Snohomish County, the cities of Snohomish and Lake Stevens, local emergency responders and interested neighbors to discuss our design plans and process. Our design team even met with Ms. Sullivan at her home, and incorporated some of her suggestions into the final design for the project — including the construction of a dirt and grass berm behind the Sullivan residence to reduce the visual and noise impacts of the project.
We even considered building an underpass and U.S. 2 local access from 87th Avenue SE for local traffic at 83rd Avenue, though those options were eventually eliminated. These options and our preferred proposal were presented to Ms. Sullivan at her home.
In attendance were the city of Snohomish city manager, the public works director, the fire chief and one of her neighbors. We also made presentations to the city councils for the cities of Snohomish and Lake Stevens at their public council meetings.
Additionally, we hosted a public meeting in November 2011 to present our finalized design to interested drivers and local residents, and to answer questions about how the new overpass will affect traffic and nearby residents.
The change to the I-5-Highway 18-Highway 161 interchange in Federal Way is quite a bit more complex than this project — partly because the volume of traffic is many times higher there (166,000 vehicles daily) than at the Bickford intersection (31,000 vehicles daily).
At the Federal Way location, we’re replacing older “cloverleaf” style ramps with new flyover ramps to reduce the number of merges drivers need to make at this intersection. The new ramps between Highway 18, I-5 and Highway 161 will improve the way drivers merge into traffic by increasing the merging distance and streamlining the way drivers travel between highways.
More information is available on the project webpage at http://tinyurl.com/WSDOTI5.
For more information on the Bickford project, go to http://tinyurl.com/BickfordOverpass.
Marysville traffic light
John Ray Marysville writes: The traffic light at the on-ramp to southbound I-5 for drivers traveling westbound on 88th Street in Marysville has reverted back to waiting for the cycles to fully complete before changing to green to allow entry to the freeway. This is during the morning rush hours when no other traffic is coming eastbound on 88th. Very annoying.
Both left-turn lanes are getting full before the light will change. And heaven help the poor soul that is waiting to turn left onto 88th from the southbound I-5 off-ramp. That light won’t ever change until every other cycle is completed at least a couple of times each.
Mishler of the transportation department responds: We had our engineers take a look at the signal at the 88th Street-I-5 interchange to make sure it’s working properly. They found that the lights and the loops that detect waiting cars are working the way they’re supposed to. However, because the traffic signals go through different cycles in the morning than they do in the afternoon, this can give drivers the impression that the lights aren’t working properly.
As John noticed, the traffic signals at the southbound on- and off-ramps are coordinated between 6 and 9:30 a.m., however they operate with a different sequence than he might be accustomed to. What happens instead is that there’s a flip-flop in the way different directions of traffic get a green light. In the mornings, the left-turn signal from 88th to southbound I-5 is “lagged.” That means rather than serving traffic turning from 88th to southbound I-5 first, then serving through traffic on 88th, the signal clears the through traffic on 88th first, then gives the green light to drivers turning left.
This flip-flop can make it seem that through traffic is getting priority over turning traffic, but it actually allows turning traffic more green time.
Here’s how: Each signal is allotted a maximum amount of “green” time — the time the light stays green. For example, the left-turn lane to southbound I-5 is allowed 35 seconds of green time in the morning. But if traffic is light, the signal may not use all the green time it’s allotted, and that extra time may be given to another direction. This is typically what happens at 88th and I-5. Like John said, there’s not a lot of westbound through traffic on 88th, so the signal doesn’t use up all its green time. That “extra” green time is then reallocated to traffic turning left onto southbound I-5. In the mornings, traffic turning left typically ends up with an average of 50 seconds of green time — an extra 15 seconds. So even through drivers turning left may have to wait for through-traffic on 88th, if that traffic is light, they’ll actually benefit by having more time to turn.
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