Rolling start traffic lights?

[cs02rm0]

Has this ever been done? Is it a stupid idea? (Probably).

There's a crossroads, with traffic lights, that I pass in the mornings which is just before I get to the M5. The vast majority of the traffic is heading towards the M5 but the traffic light timings don't seem to take account of this and so they're only green for a few seconds for each junction, with traffic queueing for over a mile up to the crossroads.

It struck me that you might get increased throughput if there were some traffic lights some distance before the crossroads that went green timed in such a way that the queue could move up to 30mph just as the traffic lights at the crossroads went green.

[The Wookie]

But wouldn't that just move the queue further back? The traffic would be hitting the roundabout faster but the bottleneck would still be there

[cs02rm0]

Hopefully because it's hitting the crossroads at a higher speed, you'll get more cars through the bottleneck, so reducing the size of the queue faster even though it is held a little further back. Hopefully.

[ZesPak]

cs02rm0 said:

Hopefully because it's hitting the crossroads at a higher speed, you'll get more cars through the bottleneck, so reducing the size of the queue faster even though it is held a little further back. Hopefully.

Better system is, and I don't know you guys have this, in Germany and on some of our roads the light goes onto orange for a few seconds before it turns green again.
People can get ready then, and the take of is often faster.

The thing is, I don't need them as I watch the other lights, and know when I'm getting green.

But, if you would draw a stop line about 10-15m (30-50ft) in front of the light, and you would make it orange for three seconds before you make it green, people would have some kind of rolling start imho.

Your solution would inevetably cause people to be stuck between both lights, thus eliminating the purpose of your first light.

[Gazado]

If anyone goes even slightly too fast and hits the 2nd set of roundabouts before they change, helloooo rear enders.

Probably a good idea in practice but not in reality.

[mike oxard]

Most of the traffic lights in the far east have a count down on the side to tell you how long till they go green, I'd have thought while he was in power Ken livingston would have assasinated anyone related to the company that makes these thought

[ZesPak]

mike oxard said:

Most of the traffic lights in the far east have a count down on the side to tell you how long till they go green, I'd have thought while he was in power Ken livingston would have assasinated anyone related to the company that makes these thought

Same as the German "3 second orange" thing .
TBH, it does scream a bit "ready... steady... GO!", but nevertheless I think it would be a good idea to better traffic flow. (Also, if it's becomming red to orange, you know you don't have to brake for the red light anymore, which saves fuel and polar bears).

[The Wookie]

cs02rm0 said:

Hopefully because it's hitting the crossroads at a higher speed, you'll get more cars through the bottleneck, so reducing the size of the queue faster even though it is held a little further back. Hopefully.

Yes, but the queue is still there, and surely the people will still be leaving the traffic lights at the same nominal rate regardless of whether they're on the junction, or 30 or 40 yards before it.

Thus the traffic goes over the roundabout faster, but the throughput is the same.

Or am I missing something.

[cs02rm0]

They leave the traffic lights they start from at the same pace, but in the rolling start system at the point at which the traffic light on the crossroads goes green they're at 30mph instead of 0mph.