Flashing lights

[hbelkins]

No, not Takumi's blog... 

Where flashing caution or stop lights (beacons, call them) have been used in Kentucky, the flashing pattern of the lights used to alternate. Right, left, right, left, repeat ad infinitum.

Noticed this week that now, at least in my area, the lights flash in unison. Both on, both off, both on, etc.

Is this a new MUTCD requirement or just something Kentucky has instituted?

Added message icon. - Alex

[roadfro]

Where two or more red beacons are used for intersection control or stop-controlled situations and they are horizontally aligned, the 2009 MUTCD stipulates that these must flash simultaneously. This is to avoid the appearance or being mistaken as a grade crossing signal. If the red beacons are vertically aligned, they can alternate.

There is no requirement on the flash pattern of yellow beacons.

[NE2]

Where two or more red beacons are used for intersection control or stop-controlled situations and they are horizontally aligned, the 2009 MUTCD stipulates that these must flash simultaneously. This is to avoid the appearance or being mistaken as a grade crossing signal or HAWK.

Fixed for you.

[realjd]

From my experience, it seems flash-in-unison is much more common across the US.

[Alex]

From my experience, it seems flash-in-unison is much more common across the US.

Flashing in unison is generally what I have seen in travels. I first noted the alternating sequence in Louisiana and Texas on a trip in 1996, every else I had traveled to until that time used the simultaneous sequence.

[roadman65]

You know its funny as how a friend of mine retired from the Orange County, FL public works and he stated that there was no guidelines anywhere that said that horizontal red beacons had to flash simultaneously.

Then quite a few years ago, there was a letter I sent to the Osceola County, FL road department about information regarding the four way stop beacon in Yeehaw Junction, FL at the intersection of FL 60 and US 441. This was back in the 90s and I had no internet yet, so I snail mailed them at the time.  They had informed me that they were going to change the operation of the signal to flash on and off and not alternatively as it was previous on the next signal overhall that was to take place.  Their reasoning behind the move, was so that motorists could distinguish between that and a railroad grade.

Interesting that my friend who fixed traffic signals was ignorant to the methods of operation of his devices he services.   Also, that my letter sent was long before 2009, so even back then some figured out this simple little thing, although I cannot see people confusing the two being railroad flashers and those overhead as the railroad keeps its lights close together.  Then again we have people who cannot figure out that EXIT ONLY on overhead signs mean that the lane they are in is exclusively for the upcoming exit, yet they are surprised when they reach the diverge point that the lane leaves the highway, so unfortunately extra precautions have to be made.

I think the flashers are more effective than the blinkers, and attract attention more to the driver. 

[roadfro]

Where two or more red beacons are used for intersection control or stop-controlled situations and they are horizontally aligned, the 2009 MUTCD stipulates that these must flash simultaneously. This is to avoid the appearance or being mistaken as a grade crossing signal or HAWK.

Fixed for you.

Re-fixed

HAWKs weren't explicitly stated in that section of the MUTCD, hence why I didn't mention them.

[thenetwork]

From my experience, it seems flash-in-unison is much more common across the US.

Indiana alternates...at least on the yellow beacons.

[Brian556]

I'm glad they adressed this in the MUTCD. I agree with their reasoning. I've seen alot of these that flash alternately.
Here's an example in Carrollton, Tx:

http://maps.google.com/maps?hl=en&ll=32.975674,-96.897547&spn=0.000036,0.025063&t=m&z=16&layer=c&cbll=32.975773,-96.897543&panoid=jH2-VXNFPfXikDlwivFm3Q&cbp=12,170.72,,0,0

[theline]

From my experience, it seems flash-in-unison is much more common across the US.

Indiana alternates...at least on the yellow beacons.

Indiana alternates the red flashers too, at least to my recollection. There aren't any on roads I travel frequently, but the alternating flashers are so familiar to me that I was shocked to hear that they aren't the standard. Next time I see one, I'll report it the location.

[PurdueBill]

Is it likely that two red flashing signal heads 10 feet apart would be mistaken for a rail crossing signal?  Am I giving some drivers too much credit? 

[Alps]

Is it likely that two red flashing signal heads 10 feet apart would be mistaken for a rail crossing signal?  Am I giving some drivers too much credit? 

From a distance, it can happen. I've done it, and I'm well aware of traffic control devices. I have the same issue with HAWKs, as do many at the FHWA (despite official record to the contrary).

[theline]

Is it likely that two red flashing signal heads 10 feet apart would be mistaken for a rail crossing signal?  Am I giving some drivers too much credit? 

From a distance, it can happen. I've done it, and I'm well aware of traffic control devices. I have the same issue with HAWKs, as do many at the FHWA (despite official record to the contrary).

And from a distance, what harm does the confusion do? If I see alternate flashing red lights from a distance, I know I should be preparing to stop at some point ahead. When I get closer, I'll sort out whether it's an intersection or a railroad crossing. In all my years, I've never had a problem with this.

[agentsteel53]

my only problem with the HAWK (apart from the stupiD acrOnym oVerrEach of its name) is that it has a valid off state.

a traffic signal should never be showing nothing; because to me that implies a malfunction.

[Alps]

my only problem with the HAWK (apart from the stupiD acrOnym oVerrEach of its name) is that it has a valid off state.

a traffic signal should never be showing nothing; because to me that implies a malfunction.

That is indeed an FHWA concern. If you ask me, it got pushed through the trial/interim process way too quickly.

Is it likely that two red flashing signal heads 10 feet apart would be mistaken for a rail crossing signal?  Am I giving some drivers too much credit? 

From a distance, it can happen. I've done it, and I'm well aware of traffic control devices. I have the same issue with HAWKs, as do many at the FHWA (despite official record to the contrary).

And from a distance, what harm does the confusion do? If I see alternate flashing red lights from a distance, I know I should be preparing to stop at some point ahead. When I get closer, I'll sort out whether it's an intersection or a railroad crossing. In all my years, I've never had a problem with this.

In my case, I ended up taking a different route because I thought there was a train blocking my preferred route. That's longer time and distance, which has an associated cost.

[hbelkins]

Saw the monthly report from our engineering support branch manager this week. He's in charge of the people who do our traffic signals. The report indicated that the flashing beacons in our district had been converted to meet new MUTCD guidelines.

[theline]

my only problem with the HAWK (apart from the stupiD acrOnym oVerrEach of its name) is that it has a valid off state.

a traffic signal should never be showing nothing; because to me that implies a malfunction.

Agreed. If you're going to put up a signal, it should always display something to avoid confusion. My opinion isn't stopping local authorities here in this area from introducing HAWKs. Check out today's story from the South Bend Tribune (act fast, because it goes behind a pay wall in a week): http://www.southbendtribune.com/news/sbt-motorists-walkers-adjust-to-new-traffic-signal-east-of-notre-dame-20130514,0,1601097.story

The page has a video that gives a clear explanation of how the signal works. I found it interesting that this signal has cameras to automatically trigger the signal, without waiting for someone to press a button.

[Ace10]

my only problem with the HAWK (apart from the stupiD acrOnym oVerrEach of its name) is that it has a valid off state.

a traffic signal should never be showing nothing; because to me that implies a malfunction.

I understand what you're getting at, but there are lots of signals that show nothing by default - railroad crossings and school zone flashing lights. Granted these have auxiliary signage to show us the context - railroad crossbucks and school zone signs - and I would guess HAWKs have a big pedestrian crossing sign near them or have some signage saying it's a pedestrian crossing.

The City of Biloxi rebuilt an intersection near a fire station and changed the emergency signal to a HAWK-like signal. It's got signage to the effect of "stop on flashing red" and plus if it was malfunctioning, the fire truck with lights and sirens blaring should be enough to let people know to stop to let the fire truck through.