Vehicle: Traffic Light
Lenticular Traffic Lights   (+8)  [vote for, against]
To reduce confusion

Around here there are some pretty confusing roundabouts. Some have seven exits, each with their own set of traffic lights and when you're driving through it, it can be very confusing which lights apply to you. To make it easier, many lights have big black hoods over them so they can only be seen, supposedly, from one direction. This helps, but it's far from perfect.

I propose ditching the hoods, and placing a clear plastic lenticular-style covering over the light. A lenticular coating is a series of thin prisms made from moulding the plastic so that light is sent in a specific direction. It's used in simple "holograms" you sometimes get on bookmarks and the like, where more than one image has been printed in columns lining up with the prisms, so it appears as a different image from different points of view.

Most new traffic lights use an array of LEDs instead of a bulb, so these could quite easily line up with the lenticular cover. The green light would only be seen from the direction chosen when the cover was designed, and all of the light would go in that direction, instead of being absorbed by a black hood.

If every other column of LEDs were wired differently, combined with the lenticular design, it would be possible for the traffic light to appear in a different state from different directions. A single unit could send different instructions to different lanes of traffic easily, cutting costs and confusion.
-- mitxela, Jan 12 2009

Baked https://en.wikipedi..._visibility_signals
Doesn't work exactly the same way, but traffic lights that do this have existed for a while. [notexactly, Nov 10 2016]

A light type called a programmed visibility lens already does this to some extent. A rigid mounting and careful set-up are required.
-- MechE, Jan 12 2009

There must be a reason they haven't tried this yet, but as I can't think of it I'm going to have to vote [+]. Very good idea.
-- wagster, Jan 12 2009

There are a couple of "lensed" traffic lights around here, for this reason. I think they are built like a telescope; a couple of lenses to put the "virtual" light source a long way back, so the tube obscures it from everywhere but the narrow target angle (but I'm not sure and I can't be bothered working out the optics myself...).
-- neutrinos_shadow, Nov 10 2016

Hmm, fair enough. The wikipedia page did not have the section on Programmable visibility signals back when I wrote this.
-- mitxela, Nov 10 2016

I thought it was called selected visibility back then (and that's what I searched for at first, pretty much fruitlessly), but WikiBlame says the word 'selected' has never been in that article. Did I switch universes? (/s)
-- notexactly, Nov 11 2016

// Did I switch universes? //

Yes, but so did everything else, so it doesn't show - except on Budweiser cans, which used to have a very slightly darker shade of red on them.
-- 8th of 7, Nov 11 2016

This would make it harder for pedestrians to work out when it was safe for them to cross.
-- pertinax, Nov 12 2016

random, halfbakery