By Bill Sheets Herald Writer
James Perrin of Marysville writes: I have wondered why the city is spending $14 million to build an overpass at 156th Street NE when there is one at 136th that could be attached to the frontage road on the north side and save big dollars.
Likewise, why are both of these overpasses in place and neither adds access to I-5?
Drivers have to go to exit 202 at 116th Street NE or exit 207 at 172nd. It would just make sense to place an on-ramp or off-ramp at either or both of these overpasses.
John Tatum, traffic engineer for the city of Marysville, responds: It would indeed make sense to add ramps to one or both overcrossings. That will be the city’s next step. Adding ramps at either location requires a complex study to obtain both state and federal approval. The city’s six-year transportation plan will have a line item next year for the study of ramps at 156th.
The city studied the possibility of adding ramps along this stretch of I-5 before building the bridge at 156th. The 136th location sits very close to the railroad tracks and does not have the space needed to economically build a fully functional interchange. If ramps were (or could be) built at 136th the city would have yet another interchange that suffers from the potentially severe traffic disruption and collisions from passing trains.
The 156th location has the space for an interchange without conflict with rail lines. It has the added immediate benefit of providing a second access route to and from the Lakewood Crossing commercial and residential areas, a benefit so clearly useful and apparent to local property owners on both sides of the freeway that they have formed a special district to tax themselves to pay a large portion of the construction costs.
We were able to get the overpass built much more quickly, and receive its traffic benefits, than if we had tried to get the permits and funding to build the overpass and ramps all at once.
Earl Hufnagel of Shoreline writes: The intersection of Highway 99 and 224th Street SW in Edmonds, at the Ranch 99 Market complex, has been a problem for a long time and an accident waiting to happen.
A change is long overdue. It would involve simply dividing the east- and westbound traffic on 224th, giving the green light to one and then the other, so that left turns (and the often-confused or over-aggressive drivers making them) don’t interfere with the straight-through traffic. Any hope of accomplishing this?
Bertrand Hauss, transportation engineer for the city of Edmonds, responds: We recently reviewed the three-year accident history of this intersection. During that time, only one accident has occurred (in 2010) involving an eastbound and westbound vehicle on 224th Street SW at that location.
Splitting opposing traffic at an intersection into phases is done only when there has been a lot of accidents there or if drivers’ sight lines are blocked. Neither is the case here.
Drivers make more than 10 times more trips per day on Highway 99 on this stretch than on 224th Street SW — 34,000 compared to 3,000. A conversion to “split phasing” would increase delays at the intersection, affect traffic volume on Highway 99 and have limited benefits to volumes on 224th. Waits for drivers on Highway 99 would be much longer since both phases for eastbound and westbound traffic would need to end before they get the green light.
Several years ago, the city looked into converting each approach of 224th Street SW into a left turn lane and a combined through-right lane. However, the right turn volumes for both directions are almost equal to the left turn-straight volumes so such a conversion would reduce the efficiency of the intersection.
Therefore, no changes will be made to the signal timing at this time. I would be happy to meet with Mr. Hufnagel at the intersection to discuss this further or answer any other questions he may have.
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