Power backup for signalized intersections

[cpzilliacus]

Seems like a good idea to me, but  is it too expensive?

Howard County, Maryland has backup at county-maintained signals (if one or more of the intersecting roads is a state highway, then the State Highway Administration usually maintains the signal, which is the practice in most of Maryland, except Baltimore City and Montgomery County).

Story in the Baltimore Sun: Howard Co. lights its intersections – even in outages

[DaBigE]

I've seen worse uses of those amounts of money. Like the article says, with the big swap to LED signal displays, power consumption has dropped like a rock, making these backup power systems much more affordable.

[myosh_tino]

I believe the city where I live (Cupertino, CA) installed battery back-ups on signals at major intersections however but when power is lost, the signals default into an all-way flashing red with the battery supplying the power.  I think the system was installed back in the early 2000's when California was going through it's "energy crisis" phase with rolling blackouts being instituted when energy consumption got too high.

[PurdueBill]

My city has done this on selected intersections--not all of them, but on certain complex ones and high-volume ones.  Replaced the incandescents with LED and installed battery backup.  Other intersections still have incandescents.

[Revive 755]

Some of the IDOT maintained intersections around Chicago have battery backup.

[roadfro]

In Nevada, I think it is pretty typical that most complex intersections, SPUI interchanges, and signals adjacent to railroad tracks (that are often affected by preemption) are equipped with battery backup.

In the Las Vegas area, I believe battery backup is installed for most major intersections. I seem to recall reading some technical design standard (maybe Southern NV RTC) that stated that signals must have battery backup capable of operating the full signal for something like two hours, then operating in all-way red flash mode for an additional two to four hours before batteries fail.

[sp_redelectric]

I find it strange that battery backups are almost standard at railroad crossings - even the most seldom used (i.e. once-a-day) railroad crossing signal, but traffic signals don't have some type of backup or even some type of "power outage" indication that is battery powered.

With the increasing number of solar powered installations for warning beacons, school speed readerboards, pedestrian signals, portable VMSes...

[Duke87]

After a nasty nor'easter knocked out power in parts of Connecticut for as much as a week in March of 2010, the City of Stamford decided to invest in a bunch of generators which they could, when needed, wheel up to the box of a powerless signal, plug in, turn on, and keep the signal running until CL&P got power to the area restored. This proved to be a wise investment when even worse storm-related outages followed Hurricane Irene the following summer.

Of course, when the power's out all over the place, you've got the opportunists to contend with. The first day they were put out, a few of them were stolen. They then had highway crews chain up the rest to prevent further theft. Shoulda done that in the first place, guys...

[KEK Inc.]

Seattle does in major roads at least.  I remember walking along in Greek Row during a snow storm one evening when power went out for 5 minutes, but the signals were still operating.  It was pitch black dark though. 

[Alps]

After a nasty nor'easter knocked out power in parts of Connecticut for as much as a week in March of 2010, the City of Stamford decided to invest in a bunch of generators which they could, when needed, wheel up to the box of a powerless signal, plug in, turn on, and keep the signal running until CL&P got power to the area restored. This proved to be a wise investment when even worse storm-related outages followed Hurricane Irene the following summer.

Of course, when the power's out all over the place, you've got the opportunists to contend with. The first day they were put out, a few of them were stolen. They then had highway crews chain up the rest to prevent further theft. Shoulda done that in the first place, guys...

Makes me wonder when I see traffic count boxes on the side of the road, not chained to anything. Whenever my company puts them out, they're always chained and padlocked. Not that it's impossible to break through, but it makes a lot of noise. (Also, for whatever reason, people seem uninterested with pulling up or cutting the tubes, even though that would be easy vandalism.)

[Duke87]

The thing with traffic count boxes is that your average citizen has no clue what they are and no motive to steal one. As opposed to your power's out and likely to be out for a while, and there's a nice generator not tied to anything...

I came across one of those traffic count boxes on a minor side street once. I was tempted to drive back and forth over it several times just to mess with it. Tempted, mind you.

[Alps]

The thing with traffic count boxes is that your average citizen has no clue what they are and no motive to steal one. As opposed to your power's out and likely to be out for a while, and there's a nice generator not tied to anything...

I came across one of those traffic count boxes on a minor side street once. I was tempted to drive back and forth over it several times just to mess with it. Tempted, mind you.

I'm tempted to pull out any boxes I come across in this area, because they're clearly not on my own company's projects. Probably even less tempted than you to actually follow through, though. Professional courtesy.

[on_wisconsin]

I came across one of those traffic count boxes on a minor side street once. I was tempted to drive back and forth over it several times just to mess with it.

Been there. Done that.

[Alps]

By the way, we test installations by stomping on the tubes. So if you want to mess with people and be green at the same time...

[Dr Frankenstein]

I don't think I've stumbled upon any signal in Québec that had a power backup. However, as mentioned earlier in the thread, it is the standard for railway signals (both mainline and crossings) simply because freight trains cannot usually stop within eyesight distance.

[Duke87]

By the way, we test installations by stomping on the tubes. So if you want to mess with people and be green at the same time...

That actually works? I would have assumed that a person's weight wouldn't be enough to trigger it.

What then, if they are installed in an area with a lot of pedestrian traffic?

[Alps]

By the way, we test installations by stomping on the tubes. So if you want to mess with people and be green at the same time...

That actually works? I would have assumed that a person's weight wouldn't be enough to trigger it.

What then, if they are installed in an area with a lot of pedestrian traffic?

At least in this area, people tend to not walk in the pavement, so it's not an issue. Also, it takes a concerted stomping effort to register, not just a regular footfall. Most people would tend to walk over a hose rather than right on top of it, so I really don't see a concern. I guess the sensitivity has to do with picking up motorcycles? Also, hoses vary in thickness - I've put out mostly thinner tubes, whereas I've seen some seriously thick ones go out that really wouldn't deflect if walked on.

[6a]

Seattle does in major roads at least.  I remember walking along in Greek Row during a snow storm one evening when power went out for 5 minutes, but the signals were still operating.  It was pitch black dark though. 

Several years ago there was a sizable ice storm in Charlotte, knocking out power to most of the city.  After three days of driving home in the dark with officers directing traffic I was pleasantly surprised to see a working light.  Turns out there was a cop there, he'd just brought his own generator and was kicking back with a hot cocoa in the patrol car.  Funniest shit I ever saw, and I couldn't even hate him for it.

[vtk]

Every time there are power outages or even reports of a single intersection without working signals, the media is quick to remind everyone to treat it as a four-way stop.  But for major multi-lane roads, people don't know how to execute that plan, and besides, that represents a significant reduction in capacity.  For major intersections, backup power would be good, but I don't know of that existing anywhere in the Columbus area.

What really scares me is when you can't see that the traffic light is even there, such as at night.  It's all well and good to treat the intersection as a four-way stop, but if the unpowered signal is invisible, it's too easy for cars to just cruise through without even slowing down.  That's why I hope ODOT's new standard of putting reflective borders around the signal heads spreads quickly.