A sign post indicates where to stop a bicycle to trigger the light.

Your Invisible Bike and You

No, you are not crazy. That traffic light did not change for you.

A red light hangs in the sky.
The red light stays that way for cyclists. Photo by the author

If you are an urban cyclist, I bet this has happened to you a time or two.

Because you choose to ride on less traveled roads, you often come to a busy intersection where yours is the only vehicle stopped at the red light. While you wait, you look over at the adjacent pedestrian signal and watch the countdown clock, which should trigger the yellow light for the opposing lane of traffic.

“5, 4, 3, 2,1, 0,” it reads, “WALK”

Wait, what? That light did not change. Why is the walk sight on again? Did I miss something?

This has happened to me a few times, in my travels. Most recently, I was on my way home from the light rail platform on my bike. It was after dark, and I was at a peculiar five-way intersection that features a freeway entrance ramp and a nearby homeless shelter. Cars were gathering speed ahead of me, and behind me there was someone shouting to the wind about forces that only she could see. I was ready to be on my way. But the red light had just declared that it was going an extra round, just for me.

At this point, you’re probably saying one of three things: “just go and press the crosswalk button, you doofus!” (I didn’t), “I know exactly what just happened!” (good for you, I’ll catch you another time), or “Oh my gosh, that exact thing happened to me.” As in all things, there are cyclists who are in-the-know about such things, and those who aren’t. That day I had encountered one of those invisible forces that affect our movements through the city, and only get explained to us through word of mouth. And so, for those of you in that last category, who have been rendered invisible by the impassive, mean-‘ol traffic signal, let me repeat: you are not crazy.

A tip from a relative led me to seek out someone from the City’s Public Works department, who explained the different sensors that are used to detect the presence of vehicles at intersections. I had always assumed that traffic symbols just run on timers. But where high-volume streets intersect with lower-volume streets, it doesn’t make sense to stop traffic at intersections where no other vehicles are present. That’s where sensors come in.

Three types of sensors are used to detect vehicles, according to Mike Klobucar, a project engineer at the City of St. Paul. One is a coil of wire embedded in the road, called an induction loop. It senses ferrous metal (steel) directly above it. That information triggers the timer in the traffic signal. The coils can be used to detect different kinds of vehicles, and at different locations, such as a bike lane. But of course, a lot of bikes are made of aluminum or carbon fiber, which the loops would not detect. And so video detectors are also used. Cameras can turn images into traffic data, which are then fed to the traffic signal. In some places, Klobucar said, radar is used as well.

An illustration of an induction-loop traffic sensor shows how an automobile travels through an electromagnetic field for detection.
Electromagnetic coils embedded in the road surface indicate the presence of a vehicle at an intersection.
A computer overlay shows a thermal imaging camera detecting a variety of vehicles.
Cameras, in this case, a thermal imaging camera, detect a variety of vehicles.

The problem, of course, is that those signals don’t always work for bicycles, or even motorcycles. Fortunately, there are work-arounds, alternative forms of infrastructure, and even legal protections that favor cyclists.

First, the infrastructure. Those streets where there are dedicated bikeways or bike boulevards are equipped with special sensors that are calibrated to detect bikes. In my limited experience, they seem to work much better than those streets without a similar designation. A cyclist simply pulls up to the familiar bike symbol indicating the location of the sensor, and boom, the light changes. Not always just-like-that, but when the signal changes, I feel seen.

The icon for summoning a light change is painted on the intersection of Summit Ave. and Lexington Ave. in Saint Paul.
The “stop here if you are on a bike” icon, at Summit and Lexington in St. Paul
A sign says "To request green, wait on" and illustrates the bicycle icon to wait over.
Signage indicating “stop here for signal” for cyclists, at Griggs and University Avenue in St. Paul

When you find yourself at a signal that requires a car-sized vehicle, rendering you effectively invisible, you’ve got two options. One is to dismount your bike, go over to the pedestrian crosswalk and press the button (or ask a passerby to do it for you). The other one is (duh) run the red light. The law has you covered there.

My friend Andy tipped me off about this. “There’s a law,” he informed me when I asked what he knew of induction loop sensors (he didn’t). The law “says when the light’s not working for you, you’re allowed to run it.” I checked. He’s right. Look at this, it’s Minnesota Statute 169.06, Subdivision 9-3.

“A person operating a bicycle or motorcycle who [runs] a red light has an affirmative defense…if [among several other conditions] the traffic control signal is apparently malfunctioning or, if programmed or engineered to change to a green light only after detecting the approach of a motor vehicle, the signal has apparently failed to detect the arrival of the bicycle or motorcycle.”

An “Affirmative Defense” means that if you can be accused of doing something illegal; you can introduce as evidence something that will negate your liability. In this case, the light wasn’t working, because the sensors did not detect your presence at the stop light. This only applies if you have come to a complete stop, you have been waiting there for an “unreasonable” amount of time, and you are not at imminent risk of being hit by an approaching vehicle.

Running a red light is not something I’m comfortable in doing. For one thing, there’s always that suspicion that I’ll get “caught,” either by law enforcement or by some passer-by. I’ve written previously in this space about representing cycling as a legitimate traffic use. As such, we have all the “rights and duties” of riding on the road. It’s of small comfort to know that it’s legit to run a red light. I would rather see the sensors work properly for everyone who travels through it. To that end, I am hoping you can help. What are your experiences as an “invisible cyclist?” Are there intersections where you have encountered signals that fail to change? Tell your story in the comments below.

I thoroughly believe that the planners and engineers who control the “gears” of the city do their jobs in good faith. In my exchange with Mike Klobucar, he assured me that the equipment at the intersection in question was being reviewed. Furthermore, “reports from roadway users are one of the best ways we have to know that something may not be working as expected,” he said. So by reaching out to the City, in this case, the Traffic and Lighting department at Public Works, you and I contribute to making our roads and intersections that much easier for cyclists to use.

Photo at top by the author

Ed Steinhauer

About Ed Steinhauer

Ed Steinhauer is a teacher and artist living in St. Paul, Minnesota.