red traffic light downtown

Ever been out on a road ride, on nice back roads, only to find yourself at a red light trying to cross a busy highway? Or maybe you ride or commute early in the morning and you’re stuck at red lights by yourself?

Chances are, you either waited patiently for a car to come up behind you to trip the sensor, or you just ran the red light when things looked clear. The former method wastes time; the latter puts you in danger of getting hit by a careless driver or getting a ticket from the cops.

One time I was first in line at a light, in front of a few cars, and none of us triggered the green. I’m betting it’s because the first car didn’t get close enough to me (so there wasn’t much mas over the sensor,) but when the light passed us by, the drivers were pissed because there was a cyclist in the way, apparently screwing things up. So I had to run the red light and hightail it out of there before I got run over from behind!

Luckily there are a couple techniques you can use to get a green light while riding your bike, and avoid angering the motorists behind you.

But first, we need to look at how these lights work. In most cases, the traffic lights are triggered by inductive loops which are placed beneath the road’s surface. You’ll notice these as you come up to the light – there are usually two parallel strips cut into the road (with wire down there, covered in a sealant that looks like caulking,) spaced to fit underneath a car’s tires.

Here is a picture of one of these buried loops:

inductive loop for traffic light

So when a big, heavy car pulls up to the light, it sits on these strips and triggers the sensor.

Bikes aren’t as big or wide, so even when the sensor is properly calibrated, cyclists need to be a little more creative…

Technique 1: Ride the Strip

To make the most of our small mass, we need to ride directly over the strip for as long as possible. (You want as much of your bicycle’s mass over the strips as possible.)

Typically there are two strips like this:

inductive loop for traffic light

What I do is slow down and coast directly on top of one strip, then trackstand for a while until the light changes to green. I usually drop one pedal to the 6 o’clock position, placing more metal closer to the ground.

(Sometimes there are three strips, in which case you can ride down the center one.)

I have done this successfully, and it’s my first recommendation.

Technique 2: Run the Red Light

It’s possible that the loop is not working, so if you can’t get the green light, you might have to just run the red light.

Obviously you want to wait for a break in traffic before proceeding!

Check the local laws to be sure, but it can be legal to run the red light if it does not seem to work properly.

In my experience, this commonly occurs in left turn lanes with green arrows. I’ve been in left turn lanes facing oncoming traffic, and they get their green turn arrow, but I still get a red light, even though I should be getting a green arrow, too.

If that’s the case, the good news is that most (if not all) other lanes of traffic will have a red light. If there’s no oncoming traffic going straight, you can probably make your left.

Technique 3: Buy the Green

I don’t recommend this unless absolutely necessary, and I don’t even know that it will help you at all (I haven’t tested it,) but I have heard that there is an easy way to trip the inductive loop, even if you’re on a bicycle…

By placing a special magnet on the bottom of your bike! There is a ready-made kit for this, as well as plenty of the special “neodymium magnets” on sale at various stores.

Supposedly these powerful rare earth magnets could create enough electromagnetic force to trip the sensor.

Technique 4: Piggyback the Cars

This technique only helps at busy intersections, but when used smoothly, it can make life easier on you.

The goal is simple – don’t be the first vehicle at the stop line.

When coming up to a light, you make your way into a line of traffic. If you have to speed up to get there, or slow down to wait for cars behind you, do it. Then you just roll up to the light behind a couple cars that will surely trigger the sensor.

Unfortunately, getting a green light on your own is never easy. And if the light is controlled by a camera, that’s totally different, and even more difficult to trigger!

(Tip: Make yourself appear as large as possible, kind of like the traffic camera is a black bear that you need to scare away!)

And if none of those tips help you, I guess it’s time for technique 5 – find a new route!

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  1. The trouble with new road bikes is that they have less and less magnetic material in them. A carbon frame with carbon cranks and carbon or aluminum wheels doesn’t hardly have anything to trip the sensors.

    The magnets may work…a friend of mine did a DIY project and said he thought it helped but no matter how much we tested it we couldn’t be sure.

    I often times (when it is safe to do so)ride a little past the stop line and wave a car up behind me to get closer if I’m first in line.

  2. Yep, carbon everywhere. Luckily for bike commuters, they should have some good ole steel in there somewhere.

    Good advice.

  3. It’s easier than all that: You just stand over the bike and lay it down sideways. More metal, closer to the switch. When the light changes, you straighten out the bike and go on your way.

  4. Another solution I’ve heard of is to use the pedestrian crosswalk button. Admittedly it’s probably easier to just run the light than make your way over to the sidewalk…

  5. I have never had bad luck triggering camera trigger lights. It may be my location uses a different light style. If it seems that the sensor is not triggering, I point my headlight at it and flick it on for a minute.

  6. Hey I want to confirm the magnets I ride a fixed gear steel bike with B-43s and the magnets will change every light with the metal strips in the ground.

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