DBWI: Electrical light on crossroads

[Gladi]

Bright day
I recently read a sci-fi which had series of electrical lights governing the traffic conduct at crossroads instead of policeman. Could have had such automated system arised, and people made to obey it w/o supervision of any kind? Would it solve our traffic problems?

[HARRY]

How does this light system work?

Light comes on the the traffic goes through, light goes off the traffic stops?

What happens if the bulb blows?

If the light is switching on and off automatically wouldn't it slow down traffic I think you still need the human factor to decide which way should flow.

[Tom Veil]

Crossroad-lights work like the traffic flagposts on residential roads: one light represents the "right of way" flag, the other represents the "yield" flag.

Traffic flagposts obviously don't work well on busy streets; that's why we have the Traffic Police. The idea is that a big, bright light is easy to see even in a busy area, so maybe we wouldn't need Traffic Police at some intersections.

They actually use the light system in some of the industrial parks outside of Pittsburgh where trucks and trains cross. It works really well for trained crew -- accidents are down 40%, if you believe company statistics -- but it tends to scare the crap out of locals who wander into the crossdocks.

[Gladi]

Bright day
In the book there were three colours for each lane. Red -"yield", green "right of way" and orange which is "change" (same as when policeman blows his whistle).

Interesting info Tom. Any idea on general application? Could it be feasible?

[BCO]

What about a wooden barrier that lowers to block the direction without the right of way, which I believe is used in some toll plazas? There could be an electric light to illuminate it, so cars don't run into it.

[Darkest]

For sci-fi ideas, I always liked the 'shifting bridge' system at crossroads. Get this: a light goes off, the ground lifts hydraulically to form a bridge. Traffic goes over the bridge straight, and under the bridge straight, AT THE SAME TIME. Then, a light goes off again, the bridge sinks down to ground level, and the railings sink into holes, and people are allowed to turn. Then it repeats.

Very science fiction, though. Need a lot of steam power for every crossroad.