Traffic Signals During Power Outages

[MooseJaw]

Hello,

What do other cities do, or what is the industry standard, for power supply to traffic lights during outages? Currently for us, we do not have an uninterrupted power supply or backup power supply to our lights, so they go dark during a power outage.

Our power outages don't usually last very long either.

Thanks in advance for your input.

 

[jgailla]

I live in a city of about 1 million.
The closest major intersection to where I live is a four lane road intersecting with a six lane road.
I don't know the road classifications, but there is a lot of traffic.
Recently a transformer blew and the light was out. There was no backup power supply and traffic was backed up for miles.
On the other hand, they got it fixed within a couple of hours.
I am not aware of any traffic lights in the city with a backup power supply, as I have seen numerous lights out over the years.

 

[ACtrafficengr]

There is a proposed change to the MUTCD recommending backup power supplies for signals interconnected with railroad grade crossings.

The proposed text reads:

Guidance:
Except for traffic control signals interconnected with light rail transit systems, traffic control signals with
railroad preemption or coordinated with flashing-light signal systems should be provided with a back-up
power supply.

http://mutcd.fhwa.dot.gov/resources/proposed_amend/npa_textshowingrev.pdf

Rumor has it there will be an announcement on the next revision by the end of the year.

"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 

[GeoPaveTraffic]

In our area there is no backup power supply for signals. We have had power outages lasting several days in the last 5 years due to ice storms. The local police / public works departments put up temporary stop signs at the largest intersection, the rest are just left dark.

 

[ABKaminski]

If you can afford it, battery back up is preferred; followed by a gas powered generator with external plug (downside, you need to know the signal is out and send public works/police department to hook up the generator). However, I have seen a situation out here in the NE where signal that frequently goes down is located at an intersection with poor sight distance. There are fold down stop signs on each approach that are manually lowered during an outage.

 

[brandoncdg]

I think over here in the Los Angeles region they like to pay the police to stand in the intersections and wave their hands. I don't see that ever changing.

How big is the battery backup that controls a simple intersection??? Or is the backup used to just flash the lights red?

CDG, Los Angeles Civil Engineering specializing in Hillside Grading

http://www.CivilDevelopmentGroup.com

 

[ACtrafficengr]

When 150 watt incandescents were replaced with 18 watt LEDs, battery backup became feasible.


"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust