SignalTraffic Forums

by **B 67** on Fri Apr 15, 2011 6:47 am

I have spotted this short unnecessary red at some intersections before and assumed it to be either a programming fault or perhaps a limitation on older controllers. But apparently it is popping up at new installations and upgrades as well. It's very annoying having a light go red, only to turn green right away.

by **coyttl** on Fri Apr 15, 2011 8:39 am

I've seen something similar to that here in the US - rare, but I have seen it. What I've seen cause it is if there's a vehicle on a side road, waiting for the green, and the controller starts to terminate the main road. Sometime after the side road has gotten the 'Next' flag, the detector input is cleared - the vehicle turned right, backed up, etc. The controller then re-evaluates and changes the 'Next' flag back to the main street. Since it can't go from yellow-green, it has to finish cycling the phase.

In this case, however, it appears as if the thru-phase is 'OR'd with the right-turn phase. :scratch:

by **2070** on Fri Apr 15, 2011 4:15 pm

It may also be that the BALL colors are an OVERLAP.

If they are, Then the "Wording" may be incorrect to keep the BALL colors green when the other Phase is going to be next. :scratch:

by **B 67** on Fri Apr 15, 2011 6:50 pm

I should point out that this is a T intersection. There's no road on the left here. So those circle / ball aspects have no reason not to stay green.

by **jab8356** on Fri Apr 15, 2011 7:47 pm

Right turn doghouses do that here. Everything is red. Then the cross streets left goes to green arrow, yellow arrow, red arrow while the main street right dog house is tied to it and the right green arrow goes to yellow arrow then off and 2 seconds later the main street gets a green thru, so there was really no reason for the yellow arrow on the right dog house to stop traffic because traffic starts up again with the green thru 2 seconds later. It just bugs me. The old system was to have a green arrow (no doghouse) for right turns that stayed on until the thru green came on. I liked that much better.

by **EPAC-EPIC-MARC** on Fri Apr 15, 2011 10:25 pm

jab8356 wrote: The old system was to have a green arrow (no doghouse) for right turns that stayed on until the thru green came on. I liked that much better.

MUTCD!!

The old way was done two ways...

EPAC Phase On input from the left turn phase of the crossing street.

EPIC four intervals mapped with Green, Green, Green, Dark codes.

:offtopic:

by **steven1981** on Sat Apr 16, 2011 1:05 am

jab8356 wrote:Right turn doghouses do that here. Everything is red. Then the cross streets left goes to green arrow, yellow arrow, red arrow while the main street right dog house is tied to it and the right green arrow goes to yellow arrow then off and 2 seconds later the main street gets a green thru, so there was really no reason for the yellow arrow on the right dog house to stop traffic because traffic starts up again with the green thru 2 seconds later. It just bugs me. The old system was to have a green arrow (no doghouse) for right turns that stayed on until the thru green came on. I liked that much better.

I totally agree with you. This particular system also bugs me. It's pointless. In New York City, a handful of signalized intersections use that sequence. There are, however, a lot of signalized intersections that use the "old system." Furthermore, there's a fairly new signalized intersection in my town that uses this system as well.

by **notMUTCDcompliant** on Sat Apr 16, 2011 11:17 pm

same thing right around here.... didn't happen on the old signals, but now does the exact sequence on the new one.... Lazy programming or limitation?

by **Troubleshooter** on Sat May 28, 2011 12:31 am

It may be to prevent yellow trap when the opposing phase goes red.

by **B 67** on Sat May 28, 2011 3:50 am

Troubleshooter wrote:It may be to prevent yellow trap when the opposing phase goes red.

Except that there is no opposing phase at the location in this video. Which is why the lights could, and should remain green for straight through traffic.

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