Foto Friday: Bike Lane Detection Loops

I am, personally, opposed to guerrilla bike facilities. Do it yourself bike paths could lead to a horror show of mismatched cold patch asphalt atop a bed of gravel intermittently transitioning to easily washed-out sand. Inaccurately planned recreational mountain bike paths are a frequent target of the ire of those opposed to erosion. Even when sober traffic engineers governed by the California Manual of Uniform Traffic Control Devices (CAMUTCD) create signs, there’s a bewildering variety of the same message. As far as I know, only the small city of Santa Clara, CA has had the vision to put the officially approved notice that wrong way bike traffic is riding in the wrong direction on the reverse side of their bike lane signs.

Guerilla Bike Lane Facility
Guerilla Bike Lane Facility at Pacific Highway northbound at the intersection with Sea World Drive, just before it becomes Mission Bay Drive

That said, I do sympathize with folks who get out the paint cans, spray chalk, shovels, stencils, tampers, and other tools and materials when confronted with a consistently irritating situation. The picture above is one example. It’s a picture of Pacific Highway northbound at the intersection with Sea World Drive, just before it becomes Mission Bay Drive. Yes, fellow San Diego cyclists, there is an induction coil under that smooth pavement, ready and able to detect the magnetic fields induced by a bicycle and relay that signal to the controller for the traffic lights at that intersection. It’s right under that bike lane bike rider stencil, but it’s finicky. I’ve gotten my best results by stopping with the front wheel right atop the helmet! However, without that sort of local knowledge, how could anyone riding a bike know there’s a detector down there, or how to get it to work? No wonder some frustrated rider, probably tired of coaching others, painted the white box and the red and white words giving precise, easy to follow instructions.

Official Bike Detection Loop
Official Bike Detection Loop

It’s a shame someone had to go reinvent the wheel, or in this case the bike detection loop marking, as there is an official (yes, it’s in the CAMUTCD) stencil pattern for precisely that message. The above example is from San Jose, CA. It features a smaller than normal cycling person image along a registration line that shows the “sweet spot” for being detected. It’s equally applicable for detection loops designed with bicycles in mind and those regular traffic lane loops set to detect bike riders and their faithful non-motorized steeds.

That’s in San Jose.

Unpainted Bike Lane Detection Loops

The City of San Diego, where it has detection loops in bike lanes or on other bike facilities, tends to not tag or label them at all. The example above, ineptly placed within a merge section of a bike lane on Regents Road southbound near La Jolla Village Drive, is typical. The casual viewer can see the hot melt seams where the detector loop was sealed underneath the surface, but there’s no indication of what was done or why that would be apparent to a casual observer or someone not a connoisseur of paving and traffic control devices. It’s a shame.