Jet City Journal: (Un)intended Consequences of Seattle's Bike Masterplan

The image to the right shows one of the consequences of Seatle's Bicycle Master Plan. Taken this past Thursday at roughly 8 in the morning, it shows a 4-block traffic back up on 7th avenue from the Westlake intersection west.

There were no extenuating circumstances causing the back-up. No accidents, police activity or anything else. Instead, it's a direct result of the decision to convert what was formerly a shared bike/car lane on 7th into a dedicated bicycle-only lane from Dexter Ave. all the way to Virginia. And it's created a serious traffic bottleneck where none existed before.

With so many riders coming up from Dexter and riding a few blocks on 7th before heading downtown, the dedicated bike lane is a good idea. But there's no reason it should extend all the way to Virginia. In fact, there's a good reason it shouldn't.

There are two sets of traffic lights close together at Virginia and Westlake. That's also where 7th ave switches from a two-way to a one-way street eastbound. Since the lights aren't synchronized, only 4 cars at a time can get across Westlake before hitting another light at Virginia without blocking Westlake. With a lane of traffic gone, it's now impossible for more than a couple of cars to queue up at Westlake to make the light at Virginia. In addition, there's now a cascade effect as more cars get caught at the lights at preceding blocks on 7th.

Keeping in mind that the photo above was taken in late July, when car traffic volume during rush hour is low, there is a strong likelihood that this problem will only get worse as the year goes on. It's not inconceivable that the back-ups could extend all the way back to the Aurora interchange.

There is an easy solution, however: end the dedicated bike lane at Lenora Ave and allow cars and bikes to share the same lane from Lenora through Virginia. That would relieve the bottleneck at Westlake and reduce or eliminate the cascade back-up it creates on 7th. As the vast majority of bikers turn south before reaching Lenora, it should have a limited impact on bike commuters. Another option would be to change the light pattern so that there are greens at Westlake and Virginia at the same time.

Still, it's odd that no one thought about these issues before and, at a higher level, raises questions about the overall Bicycle Master Plan. How much research was done before determining where dedicated bikes lanes should be created? Does the plan offer the flexibility to adjust routes if assumptions about car and bike traffic prove erroneous? Who is actually monitoring the impact that these new bike lanes are having for traffic and traffic patterns in the city?

Now that more of the master plan is in effect, it might be time to reassess these questions. It will be interesting to see whether our bike-loving mayor has the interest of all commuters in mind or just those of his fellow bike commuting constituency.