SignalTraffic Forums

by **DigitalMCO** on Tue Jun 25, 2013 2:43 pm

Here’s a question that maybe some of our signal techs on the forum could answer, especially those who live in areas of the country that receive large amounts of rain and or high humidity.

Every time we have a heavy rain here in the city, numerous intersections go into flash mode (all red). It’s always the usual suspects and I was curious as to what the MMU sees as an issue to cause it to go into flash mode?

I don't believe it's a power failure related issue as I’ve witnessed intersections go dark and then return to normal when the power returns. Could this have something to do with the timer (being a computer after all) failing due to high moisture content or could it be something as simple as wet wiring causing the MMU to sense some sort of resistance or short circuiting issues.

:scratch:

by **notMUTCDcompliant** on Tue Jun 25, 2013 3:07 pm

Sounds like some of the underground cables aren't insulated properly, and when water gets in there, it could see stray voltage on a conflicting indication, then drop out.

by **EPAC-EPIC-MARC** on Tue Jun 25, 2013 3:14 pm

My vote goes to bad insulation on the wires as well. We get lots of rain here..and snow and ice! Never seen anything out of the ordinary

I am waiting for an MMU to come out with a rain-fault feature! :lol:

by **notMUTCDcompliant** on Tue Jun 25, 2013 3:23 pm

that's easy! hook up a standard rain sensor to a standard input, then you can log it!

by **EPAC-EPIC-MARC** on Tue Jun 25, 2013 3:28 pm

notMUTCDcompliant wrote:that's easy! hook up a standard rain sensor to a standard input, then you can log it!

I bet somewhere, somehow, some agency is contemplating a rain fault option on their cabinets :crazy:

by **Econo101** on Mon Jul 15, 2013 8:41 pm

EPAC-EPIC-MARC wrote:
notMUTCDcompliant wrote:that's easy! hook up a standard rain sensor to a standard input, then you can log it!

I bet somewhere, somehow, some agency is contemplating a rain fault option on their cabinets

I can bring it up at the next office meeting......

by **Canuck_in_TX** on Mon Jul 15, 2013 8:56 pm

That happens a lot in Bedford, Texas. We finally have had some good rain (2 days in a row now - much needed!!) and as always, flash mode for a couple of intersections in Bedford. Sometimes they'll put little stop signs out in all 4 directions to go along with the flashing red - probably because many are clueless here on what to do with a flashing intersection.

I saw a car one night in my area that approached a flashing caution and stop [normal after 12:30am with the main street flashing the caution yellow) and even though no cars were in sight at around 2am, continued to wait. They then would accelerate slowly and stop, still unsure what to do. :rant:

(Yep, you know who was waiting on the flashing red direction - me).

by **2070** on Fri Jul 19, 2013 9:20 am

Moisture any place in the traffic signal control device......

by **DigitalMCO** on Sat Jul 20, 2013 2:28 pm

Moisture is the correct answer, but where was it coming in from?

The other night we had some heavy rains and four intersections went into red flash along the bus route I was driving. On my final trip I came upon a couple of signal techs and asked WTF. Why is it every time it rains we have a rash of failures? Because all of our poles are on breakaway bases, there are terminal blocks for wiring in each pole to make it easier to repair after a knockdown. Unfortunately some of the access covers allow water to penetrate the pole during a heavy rain and well, you can guess the rest.

As for people not knowing what to do at a flashing red, I also encountered this the other night as well in my bus. Fortunately on my next couple of trips the police were kind enough to sit along the side of the road with their lights activated. It's amazing how many people seem to remember what a flashing red means then. :lol:

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