Wednesday, October 10, 2012

Traffic Lights

Occasionally I come up with ideas for how to improve existing products or procedures. For a long time, like many others, I’ve sat at intersections and contemplated traffic lights and intersections in general. Clearly I’m not the only one. Here are three things I believe make intersections better (at least until everyone has a driver-less car and then they'll be to scary to watch)

Incoming Traffic Monitoring

My first complaint is not how long I have to wait, but the fact they don’t take “incoming” traffic into account; only traffic sitting and waiting at the light.

This scenario happens to me regularly. I am sitting at a red light with to no cross traffic. A vehicle begins to approach the intersection (figure 1). The light turns red and they have to stop.
figure 1

Now I get to go, and the other car sits there with no cross traffic (figure 2). Had the light stayed green in the other direction two more seconds, that car would have never had to stop. By the same token, with no cross traffic I’d have never been sitting at a red light in the first place. If we could make lights account for incoming traffic, anecdotal evidence suggest there would be savings in terms of gasoline usage.

figure 2

Lights with Feedback

Now let's address wait times. I have been assured by a civil engineer the longest you’ll ever have to wait is 2 minutes. That may be true, but what about lights that get so backed up have to wait two or three cycles.

Perception is reality, and with that in mind red lights are red for a long time. I believe this is a combination of  stopping sucks after you've been going fast, and not knowing when the light will change.  You can see lights in the cross direction and have a good idea, but what if lights gave more immediate feedback?

I propose making all traffic lights work like load bars. The picture below is an example of a green light. The dark green outline represents green light that stays on the whole time the light is green. The brighter green represents light moving right to left, it’s intuitive. Someone who’s never seen this will know something is going to happen when the green runs out.

Logically, it goes to yellow, and has a similar load bar motif. Yellow would move faster because the light is yellow for less time. The point is that at a glance a driver can get an idea when the light is going to change.

The system is not perfect. A gander at the next image may point out why rather quick.
Assuming red lights work the same way, true the feedback is nice, but apprehensive drivers may jump the gun. I don’t have a great plan for that, but my initial thoughts would be to change to green before the red timer runs out completely.

This system does have the added benefit of having more light. The surface area of the border can be thick enough to be greater than the surface area than current lights. Led panels can be made to support a variety of colors and have other information built into it them like turn arrows and yield symbols. Another added bonus is they can all be made the same since their display is programmable; no need for special turn signal lights.

Point of no Return Line

Finally, an intersection idea that needs no figures and can be put into place right now with a can of paint, “Point of no Return” lines. I’d guess they’d be yellow lines painted on the road perpendicular to the direction of traffic a ways back from the intersection (I guess I could include a figure here). If you are going to speed limit, and you are still behind the line when the light turns yellow, you should come to a stop. By the same token, if you are across the line when the light turns yellow you should be able to continue at the speed limit without any problems.

The “Point of no Return” line shouldn't be attached to any laws, though it could be useful for prosecuting someone who has caused an accident by running a red light. “The video clearly shows the plaintiff was beyond the line when the light turned yellow (and there would be a video if cameras took incoming traffic into account like the first idea).

For me there are times I’m not sure how long the light will be yellow. Perhaps I’m just not good at judging the distance. There have been times I've come to a quick halt because a light turned yellow, and there have been times I've caught the first half-second of a red light as I flew through the intersection. A line could put some of those concerns to rest.

I’m not saying these will happen. I’m not even saying they should happen. I’m just sharing the things I think about while waiting at a red light.


Jake said...

The purposed idea of a load bar traffic light i believe oversees the precautionary measures of colorblind drivers. The order of the lights respectively, red, yellow, and green, are indicators for those drivers. Likewise all vertical traffic lights keep the the same vertical color pattern.

However with the same technology used in toll booths for snapping pictures of vehicles without EZ-Tag stickers, you could improve the moderately used traffic stop.

Anonymous said...

I am sorry to say that, but I think you missed the point. The entire idea of this system is to slow down cars so that they can't be speeding. It prevents from driving too fast.

James Pryor said...

This post isn't about speed, it's about traffic light efficiency. I think you might be referring to speed bumps.