Institute for Practical Bicycle Video Detection Research

ENOUGH of all this Bike School stuff for the moment. Let's do something pretentious. Hence the post title. Any of you are welcome to purchase the rights to it from me if we agree to suitable financial terms.

In English, this post is about how to get traffic signals to change for you when you are on a bike, and not those namby pamby induction ones, but the big video cameras. This is a tough one. HERE, I talked about induction loop signals. Amusingly, Rantwick, HERE, tested that tired old theory that magnets will help and found they don't.

Today, I delve further into a more mysterious area of traffic signals, the Video Imaging Vehicle Detection System (VIVDS in traffic speak). If you search around on the internet, you'll find two classes of information about VIVDS and cyclists. The first, epitomized HERE (regrettably, since it is usually FULL of good stuff), HERE, HERE, and HERE (among dozens of others), basically give no useful information at all about what the traveling cyclist needs to know to trigger such a system. All they say is "these are great for cyclists." Well, it ain't necessarily so. What these articles don't tell you is that cameras only work well when properly installed and calibrated, and presuming that the windstorm that hit last night didn't swing the camera around 79 degrees (which I have seen happen). Fortunately, there is also a second kind of information, which completely ignores bicycles, but which DOES give solid information. As it turns out, those "these are great for bikes" articles didn't LOOK at the second articles. Which is why you are fortunate to be reading this. Consider yourself "cutting edge."

FUNDAMENTALS

If you aren't the type of person who simply is highly trusting of the traffic types that do stuff like create door zone bike lanes, or stop signs just for the heck of it, read on. The first two photos are from a Texas A&M study on VIVDS system effectiveness, and the third is from a Purdue study. You can read these for yourself HERE and HERE. In truth, I forgot to copy the link when I pinched the pictures, but you'll see them in various forms in the links, along with all kinds of trivia it didn't occur to me might apply to cyclists.

Anyway, a VIVDS system works by detecting pixel changes in a "zone" that is programmed into the system when the camera is installed. You may notice that the cameras are usually installed fairly high in the air. This is so they can get a good view of the area leading up to the intersection stop line without also capturing clutter such as the horizon. As you can see in the first photo, the camera is aimed at the stop line and the roadway leading up to the stop line.  The horizon is purposely out of view. IF you happen to favor riding shoulders in such a situation, you may also notice that the shoulder disappears out of the view of the camera. Thus, we learn our first lesson. WHEN YOU WANT TO TRIGGER A CAMERA SIGNAL TO CHANGE, MOVE INTO A TRAFFIC LANE WELL BEFORE COMING UPON THE STOP LINE. This way you will be detected. Few cameras will be set to detect things on the shoulder, sidewalk, or median. More often than not, they are puposely set to AVOID detecting such areas. These things create false signals. Don't be a false signal unless you like waiting forever.

As you may see in the second photo, the camera is not simply set to just read a big blob waiting patiently for the light. It is broken into zones, so the camera can detect traffic approaching the intersection as well as traffic waiting for the light. This is another reason you want to move into the traffic lane well in advance of the intersection. However, take a good look at the Stop-Line Detection zones and imagine the situation of a cyclist that stops where the nose of the gray car stopped. That cyclist has given up at least half his/her pixels to the zone boundary. What's more, if the vagaries of weather have tilted that camera up just a smidge, the cyclist will be outside the detection zone altogether. This leads us to the second lesson. WHEN STOPPING FOR A CAMERA, STOP A BIT BACK FROM THE STOP LINE SO THE CAMERA SEES YOU. This also brings up the third lesson. WHEN DECIDING WHERE TO STOP, LOOK AT WHERE THE CAMERA POINTS. I have seen cameras spun by the wind around North Texas. The zones will move the way the camera has shifted. You want to be IN that detection zone. If the camera is pointed towards Oklahoma, it won't see you unless you are on your way south FROM Okalahoma. God LOVE those OKIES, except for the ones that drive red pickups with OU stickers on them.

You may also encounter one of these cameras at night. Well, they do not work by magic and they don't have IR or some special night vision. They get triggered by what they see. One more reason you don't want to depend only on a reflector at night. I do not know definitely if it helps to point your light at the camera, but it seems to me that pointing a blinky headlight at a camera at night ought to catch its attention. I've tried it and the light triggered, but it might have changed anyway. Still, I often check to see how far I can lift my front wheel when I am stopped at these types of light in the dark. Which brings up the final rule, AT NIGHT, NINJA CAN WAIT FOREVER! You KNEW there was some reason you needed to ride with lights at night. Now you know at least one reason why that you never read in the bike books. For all you know, there MIGHT be a ninja in that middle lane.

PS: As a duly designated remote tester, I EXPECT that you all will journey to some video signal camera you've never been able to trigger and give all this high tech stuff a go. I hope to hear of success, but these can be tricky devils. Unlike the induction units, there are not cuts in the pavement to clue you in. AND, if you can get me in touch with Eli Mowbray, of the Santa Cruz Public Works Department, you get double points. I suspect that guy can fill in the gaps a casual internet search leaves behind.