Thursday, December 3, 2009

"Bike Box" - a.k.a. "Car Box"

Update: I rode over this spot today. The signal for the cyclists is in fact before the real stop line. So the car was parked in the wrong place, sure, but it's not a bike box.

There is however an real bike box now at Scott in the wiggle in San Francisco.

Today I was riding east down Evelyn from the Mountain View Caltrain station. Frequently on this route I will then take a left on Mary to get onto Central Expressway to head to work. The left turn there has an advanced stop line for cars with a triangular spot for bikes to set up their turns. There is a lot of value for a bike to make this left turn from the front of the queue because you need to be able to set up a proper line as you turn left, so as to be able to take a straight line over the Caltrain tracks.

This morning, I wheeled up to the bike box and there was a car pulled up past the stop line and into the bike area.

Unclear on rhe whole bike box concept - Evelyn and Mary, Sunn... on Twitpic

I sent this out in a tweet and Fritz asked "There is a bike box there?". I had to think about this - my kneejerk reaction is "Yes", but is it a legitimate "Bike Box" - e.g. is the striping done like that specifically for bikes? I thought I recalled there being a bike symbol painted there - the tiny bike symbol with the vertical line through it to indicate where the bike sensor is in an intersection, but I wasn't 100% sure. I figured I would take a look at the Google Maps and check it out.

View Larger Map

Amusing. There is a car stopped in the bike box in the Google Satellite View, on the left side of the intersection. You can see how the striping is set up if you look at the right side of the intersection showing the left onto Mary from WB Evelyn. And no, that car is not in the process of making a left...

You can look at the ground there in the streetview picture, I don't see a bike marking. I'll have to go check it out again. What is clear, bike box or not, the first line is the stop line.

Not the first time I've ever seen a violation captured by Google....

View Larger Map


Michael Graff said...

There's no such thing as a "bike box" (or advanced stop line) in the California MUTCD or HDM (or AASHTO for that matter). Nor is there any vehicle code that would apply.

That looks like an ordinary stop line which would apply to all drivers. So it doesn't matter who is in front of the stop line, it's the same violation.

Michael Graff said...

Also, I think that stop line is where it is to keep people turning north-to-west from hitting people waiting to turn east-to-north, because of the angles. Note the curved dashed line in the sat photo.

murphstahoe said...


I'll ride by today to see if the marking/sensors are there.

Is this marking strategy basically giving the cars a purely horizontal stop line despite the fact the crosswalk needs to be diagonal?

murphstahoe said...

And how does no such thing as an "advanced stop line" correlate with this...

Michael Graff said...

By "advanced stop line", I mean this:

One stop line for cars, a second stop line for bikes, with some way for bikes to pass stopped cars to get to the front. It's another term for bike box (or in-line bike box as John Allen calls it).

There are no approved standards for bike boxes in California or AASHTO, so if there's a stop line it's for all drivers. Even the bike boxes in Portland are experimental.

The streetsblog example is a different meaning of advanced stop line. One reason for this type of ASL is to improve pedestrian visibility, in order to prevent a "multiple threat" collision.

But that example isn't a bike box. Cyclists have to stop behind the same line.