Pedestrian crossings aren’t a new thing. Cars and pedestrians have shared streets longer than we usually think, we just have to roll back to the Roman Empire. Yes, cars were powered by animals (including humans), therefore much slower, but being ran over by an ox and a couple of wooden wheels sounds as dangerous to me as being ran over by a Bentley. Even if it was slower, and less fashionable.

So, in Pompeii ruins there are a few examples of the first pedestrian crossings. As Wikipedia says:

Blocks raised on the road allowed pedestrians to cross the street without having to step onto the road itself which doubled up as Pompeii’s drainage and sewage disposal system. The spaces between the blocks allowed horse-drawn carts to pass along the road.

Sounds like a good idea to avoid stepping on the… let’s call it “waters” that moved along the streets. And here we are, 2000 years later, following the same design, as if nothing had changed. The only difference is that nowadays instead of blocks raising on the pavement, we have lines painted on it. As if it was a “flat design” version.

The main problem, if you ask me, is visual, contrast, counter-shape. The fact is that, the way the lines are drawn, a person standing in the middle of a pedestrian walk is way less visible than it should. If we reduce the shapes to basic geometry we could easily spot the flaw.

Figure A, the most common design for pedestrian crossings. Amount of counter-shape: between 63x to 47x

Consider Figure A, the most common case, with the lines drawn parallel to the traffic. For this example we’ll assume that the pedestrian isn’t Lady Gaga using fancy sparkling colorful clothes, just a regular human being, with regular clothes that don’t pop-out as easy and might blend with the background. During dusk, dawn and night, when light conditions are less favorable, a car with the lights on (coming from below in this case) will cast X amount of shadow.

You can see that, when the pedestrian is stepping through the lines, the amount of white lines that gets blocked is variable, and when he’s between two of them, he’s not blocking much.

Figure B, a simple redesign. Amount of counter-shape: constant 129x

Now let’s check Figure B, in this case the lines have been painted perpendicular to the traffic. With the same light conditions, the pedestrian will block more white lines, to be exact more than double (I ran some numbers), and that amount will be constant, no matter where the pedestrian stands.

Figure C

And if you were wondering it, a pedestrian standing right over the line will block even less amount of white lines.

I know, I know, this is not a scientifically accurate example, but it helps getting to the point, and I’m sure you will agree with me that a vertical object standing on a perpendicular line, is way more visible than the same object on a parallel line.

There are even more facts that make the redesign better than the current one: probably it’s easier for the driver to visualize the distance between the car and the lines, and judge his own speed.

And it will only take 3.7% more paint to cover the same area with perpendicular lines instead of parallel ones.

More on Pedestrian Crossings: http://en.wikipedia.org/wiki/Pedestrian_crossing