Emergency Lighting Studies

SoFlaDep

Member
Aug 24, 2010
27
South Florida
I know there have been many studies on emergency lighting. Our agency switched from all blue to red and blue saying that red was better for day use. I have since heard that blue LEDs are actually superior during the day at grabbing attention and that red blends in with stop signals. Does anyone have any official studies on emergency lighting? Thank you and stay safe.
 

Stendec

Member
May 21, 2010
816
There haven't been "many" studies, and those that do exist don't carry a whole lot of scientific rigor. They also aren't very "deep" - they don't typically address the physiology and psychology of perception, the way people process visual and audible signals, and how motorists construct responses to unusual circumstances like encountering emergency or service vehicles.


Most of what we think we know about emergency signaling we know because, well, everybody knows that (insert theory of choice here.)


There would also be a number of practical and ethical issues involved in studying signal effectiveness, also. You just can't fake emergencies or run up on somebody's bumper lights blazing to see how they react, even though it might be a hell of a lot of fun.


Someone will cite the Florida Highway Patrol paper, but NHTSA doesn't have much, nor does NIJ. NASA and the FAA have done work on aircraft conspicuity, but I don't think the emergency vehicle equipment manufacturers would be too happy if we used the same standards as aircraft, essentially a couple of marker lights and plain old strobes or beacons.
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
There is a CHP study (somewhere) that indicates slow flashing large lamps are better than a buch of small fast flashing. Looking for it now...
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
SAE study


http://www.sae.org/standardsdev/tsb/coo ... mp0810.pdf


General Study, with work cited


http://www.emergencydispatch.org/articl ... stems1.htm


The prop to allow quad flash LEDs.... not really what i was looking for..... http://www.chp.ca.gov/regulations/pdf/06-18isr.pdf


and then there's this... doesn't seem very indepth..


http://policedriving.com/article145.htm


a brit study


https://dspace.lboro.ac.uk/dspace-jspui ... AR2344.pdf


reflective stuff


http://www.usfa.dhs.gov/downloads/pdf/p ... fa_323.pdf
 
Jun 26, 2010
324
Massachusetts
Give it some time and there will be one done by the Massachusetts State Police.


They've pretty much had it with getting whacked by drunk drivers so they've decided to start a lighting study to see if lights may be part of the problem.
 

led0987

Member
Jul 13, 2010
34
Joplin, MO
Stendec said:
NASA and the FAA have done work on aircraft conspicuity, but I don't think the emergency vehicle equipment manufacturers would be too happy if we used the same standards as aircraft, essentially a couple of marker lights and plain old strobes or beacons.

Point of fact- much of the automotive warning technology we enjoy today was created for the aviation industry to meet the need for better visibility for aircraft during the aviation boom in the 30's, 40's, 50's.. etc.I believe I read somewhere once before that both Whelen and Federal Signal created their first rotating halogen beacons for the aviation industry, which bled to applications in automotive. Strobe technology, and now even the new LED scene light technology was invented to fill the need for better aircraft visibility.


One can even suggest you can follow new lighting technologies introduced in aviation to preview what will be designed for automotive in the coming year.


Also- both the FAA and NASA I am sure have much more stringent requirements for light output and low failure rates that we should all hope automotive lighting manufacturers look to meet those requirements.
 

SoFlaDep

Member
Aug 24, 2010
27
South Florida
Thank you all for the responses. I prefer to go back to an all blue lightbar with amber and red toward the rear. The other night I was going to a call running code 3. My zone partner joined in and was behind me. When I looked in my rearview, it seemed as if he had two lightbars. The red leds and blue leds were not even. The red floated up higher and the blue stayed level. It looked like crap. I am going to review these studies and see if I can convince the agency to go back to all blue. Like someone said most of the time these studies have no real relevance and it comes down to preference and state laws. Thank you again.
 

nerdly_dood

Member
Jun 15, 2010
2,312
Georgia
My experience:


BLUE


------------------


Hardly visible in the day. Appears "lower" than other colors at farther distances, at all times of the day. Very visible at night. Blue LEDs at night are literally blinding, with specific reference to a Federal Signal Legend in all-blue. Blue rotators or strobes are much better at night than LEDs since they make sure they car is very visible but not blinding.


RED


------------------


Very visible in the day. Appears at proper height at any distance. Visible at night, but with other red lights like cars' brake lights and traffic lights, blue stands out more.


AMBER


------------------


Similar visibility in the day and at night - at all times, visibility is between that of red and blue.


ROTATOR


-----------------


They convey a sense of urgency. Visibility good in the day and at night. Flash speed is best at appx 100 FPM with mirrors, 120+ without mirrors. In a lightbar with diamond mirrors, one or two rotators at appx 175 FPM can be good but more than that and any mirrors in the lightbar totally ruin the "pop".


HALOGEN FLASHER


----------------


Does not convey much sense of urgency, but adds plenty of visibility at long distances at all hours of the day. Best used with simple, slow alternating flash patterns; double-flash halogens don't work as well.


STROBE


----------------


Less effective than rotators in the day, however white strobe hideaways and intersection lights are very effective. Very effective at night with multiple-flash patterns. Pretty worthless with single-flash patterns.


LED


-----------------


Very visible in the day, blinding at night. Best used with either quick alternating patterns, or a flash pattern with very quick flashes before a moment of steady glow... some patterns rely on "off time" rather than "on time" in their flash patterns, and I find these to be much less effective.
 

shues

Lifetime VIP Donor
May 21, 2010
10,276
NW Indiana
SoFlaDep said:
Thank you all for the responses. I prefer to go back to an all blue lightbar with amber and red toward the rear. The other night I was going to a call running code 3. My zone partner joined in and was behind me. When I looked in my rearview, it seemed as if he had two lightbars. The red leds and blue leds were not even. The red floated up higher and the blue stayed level. It looked like crap. I am going to review these studies and see if I can convince the agency to go back to all blue. Like someone said most of the time these studies have no real relevance and it comes down to preference and state laws. Thank you again.

What you are describing here is a result of having a prismatic day/night rear view mirror and happens regardless of the manufacturer of the leds. The effect is more pronounced with two colors that are distant in the visible spectrum, but is even noticeable with more nearby color combinations such as red and amber.
 

03crownvic

Member
May 8, 2010
1,033
Louisiana
The human eye can also produce the same "floating" effect with colors, as I've often noticed the different colors of red and blue, especially in LEDs, do not seem to be lined up on the same level in many lightbars, especially from a distance, and it does look very odd. However, it seems to be more apparent in some of the various bars on the market rather than others, probably because of number of diodes in the LEDs, their positioning, etc. If you do have the option with your lighting color presentation, mixing red and blue is the ideal way to go, as it obviously covers the classic day/night argument. However, blue's visibility has progressed these days to the point where it is very effective when used by itself.


Back in the my LE days in Arkansas in the early 80s when we still used Visibeams, we had all blue on our PD cars. Being from Louisiana, where red/blue was often mixed, I decided to change to red/blue on my unit. I borrowed a red dome from the FD guys and used it for a couple of days until I found out from the chief that the state code dictated red was strictly for fire/EMS use, so I had to remove it and return to all blue. The all blue was very dim and hard to see in the daytime, so for kicks, I borrowed a clear dome from the FD to try out. Since I didn't have any blue bulbs to use under it, I had clear on one side of the bar and blue on the other. That lasted for about half of one shift as it looked like the bar was missing the colored dome entirely. I went back to all blue domes, but soon put 100 watt 4509 aircraft landing bulbs in the bar to make it brighter, as those 35 watt 4416s just didn't cut it. Of course, it slowed the rotation down so much, I had to alternate the bulbs and have one of each per end. I eventually changed to the 50 watt 4464, which worked out best. Coincidentallly, Arkansas eventually changed their color codes and lets red and blue be mixed for LE use now.
 

SoFlaDep

Member
Aug 24, 2010
27
South Florida
Thank you for the information. I read some of the studies and being in Florida I am somewhat familiar with the FHP study. I passed an FDOT unit the other day on the I-95. His lightbar was all blue, with blue amber warning deck lights, and corner strobes. Truthfully, you could see him plenty far way. The car look more professional than having all these mixed colors. For example, our cars are R/B/R/B/R/B/R/B with an amber traffic advisor built into the first layer of the bar. It looks like a circus when the bar is lit up. Most of us have had our amber bar turned off b/c it drowns out the red and blue. BSO has the legends in all blue with a red and amber pod to the rear. You can see them just fine during the day and in the front they have flashing LED takedowns which are very effective. I think one color with two amber/red pods to the rear seem more effective overall. I am not sure what FHP is going to do since the Javelin is no longer available. Beside, FL law says police cars must have blue lights on their lightbar. For a while FHP was all red during the day and now they have the middle of bar flashing blue.


Another thing I do not understand is the lack of uniformity in regard to emergency lighting colors state to state. We had a guy fail to stop for one our marked units b/c he was from New York and I guess NY police are all red. Someone told me in New Mexico tow trucks use blue lights. There was some talk of FEMA pushing for a uniformed light designation but I guess nothing came of it.


Thanks again for the responses. Be safe.
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
Colors need to be alternated against one another. Split lenses/heads and red/blue next to each other look purple. A local dept has an arjent that alternates the blue against the red and one where pairs of red and blue together flash. The second one looks like a purple glow. On the first one both colors are seen clearly in day and night. Nice large chunks of single colors flashing against each other does the trick.


So... the setup of how the colors flash is more important than the colors themselves in my opinion.
 

NPS Ranger

Member
May 21, 2010
1,988
Penn's Woods
If there was real science in these studies, if there were known variables that could be quantified, then the studies would all conclude the same thing. They don't. Some say blue is best to the rear, some say amber, some say slow alternating flashes of the same color are best, some say alternating colors are best. The problem is that people in different parts of the country have come to expect certain colors for police and other colors for fire, still others for wreckers etc. People react in these "studies" according to what they respond to behind the wheel. Yes you can show that X color is more visible than Y color at 1000' in Texas, but then in California you may show that Y is more visible than X.


Reminds me of the hype surrounding the slime-green color for fire apparatus in the 60's, a NY doctor decided that since the eye was more sensitive to green than it was to red, all fire apparatus should be painted slime green. Only problem was, the green trucks had a higher accident rate and so the whole concept was dropped. People didn't yield for the trucks because they didn't identify them as emergency vehicles, and/or they fixated on the bizarre color and hit them, rather than waking up and avoiding them.


When the MSP used the old sealed beam Unity beacon, or the Ohio DOT used alternating par-46 amber flashers, people could see them for miles and knew exactly what they meant. These days almost every state police unit looks like a Christmas tree and when vollies are on scene with 6 or 8 vehicles using lightbars/headliner bars/decklights/license lights/HAWS it just dilutes the urgency of the lighting so that little by little, people just don't pay attention anymore. I'm waiting for my rural newspaper carrier to get an amber Liberty and HAW's.
 

NPS Ranger

Member
May 21, 2010
1,988
Penn's Woods
Also bear in mind that the studies mostly took place when halogen and strobe were the rule. With halogen blue is the dimmest color photometrically, with strobe red is the dimmest. With LED's blue and red can now be blindingly bright, brighter in many cases than amber LED's. Just serves to confuse comparisons among older studies which recommended amber because it was most visible.
 

JohnMarcson

Administrator
May 7, 2010
10,971
Northwest Ohio
At this point my theory is that all colors are bright enough.... it's a matter of flash speed and limiting mixing of colors.
 

Skippy

Member
Jul 3, 2010
423
Florida, USA
SoFlaDep said:
... For example, our cars are R/B/R/B/R/B/R/B with an amber traffic advisor built into the first layer of the bar.

Any idea why they don't put the colors together instead of alternating?
 

SoFlaDep

Member
Aug 24, 2010
27
South Florida
Skippy said:
Any idea why they don't put the colors together instead of alternating?


I really don't know. To be honest, I really don't think they know any better. When we gives suggestions, we usually get a " I know what I am doing" response. Some guys have switched their light bar to have all blue on one side and all red on the other side with their amber bar turned off. This has increased visibility tremendously. If I use my amber bar, it is without my red/blue lights activated. It has a lot more effect on traffic as running all the lights together washes out the red/blue. I still think with LEDs one color on a lightbar with a few different color pods to the rear seems to work just fine. Our slick top cars have their amber directional separate from the other lights and it seems to have a might greater impact.
 

tnems7

Member
May 21, 2010
407
USA Nashville Tennessee
Several compilations and review of studies are described by research just recently published in Best Practices for Emergency Vehicle


and Roadway Operations Safety for the Emergency Services


http://www.aiff.org/hs/EVSP/BestPractices.pdf


I suggest you review pages 84-92. The Arizona, Florida, Phoenix, and USFA/FEMA research are described.


In 2007 the USFA, in partnership with the U.S. Department of Justice’s (DOJ)Office of Justice Programs (OJP), entered into a Cooperative Agreement with


the Society of Automotive Engineers (SAE) to look at the issue of non-blinding emergency vehicle lighting. The SAE worked with the researchers at the University


of Michigan Transportation Research Institute (UMTRI) to conduct this research. The results were published in a USFA report titled Effects of Warning


Light Color and Intensity on Driver Vision in October 2008 (Figure 6.20).


This report was part of a program of research on how warning lights affect driver vision and how those lights can be designed to provide the most benefit


for the safety of emergency vehicle operations. To view and download the entire Effects of Warning Light Color and Intensity


on Driver Vision report, go to the SAE website at:


http://www.sae.org/standardsdev/tsb/coo ... mp0810.pdf


There is a formal 2005 studiy from emergency vehicle crash data that is mentioned by the U.S. Fire Administration report:


http://www.usfa.dhs.gov/downloads/pdf/sae0905.pdf
 

NPS Ranger

Member
May 21, 2010
1,988
Penn's Woods
tnems7 said:
Several compilations and review of studies are described by research just recently published in Best Practices for Emergency Vehicle
and Roadway Operations Safety for the Emergency Services


http://www.aiff.org/hs/EVSP/BestPractices.pdf


I suggest you review pages 84-92. The Arizona, Florida, Phoenix, and USFA/FEMA research are described.

The domain aiff.org is for sale. To purchase, call BuyDomains.com at 781-839-7903 or 866-866-2700. Click here for more details.
 

tnems7

Member
May 21, 2010
407
USA Nashville Tennessee
I have the document as a pdf file but I am not getting it at the IAFF web site with that address. It is posting a page not found notice.


I resent the query and now I am getting a different link:


Try searching http://www.iaff.org/hs/EVSP/Best%20Practices.pdf


NPS Ranger and others, if you are still unsucessful, send me an email at richardland@comcast.net and I will attach the document in my email reply.


I received this info in my email from the Dept. of Homeland Security entitled: Emergency Management and Response Information Sharing and Analysis Center


(EMR-ISAC) INFOGRAM 35-10 September 2, 2010
 

tnems7

Member
May 21, 2010
407
USA Nashville Tennessee
NPS Ranger said:
Thanks, I finally got it.... 62 MB, wow!

Sadly, the fact that this is a book, 164 pages is going to scare a lot of members from checking the research, and there is a massive list of links in the back of the book. But only twenty pages or so actually apply to warning lights and devices.


One concept that I want to mention. Just because you have multiple vehicles on scene doesn't mean every one of them needs to have their full emergency warning devices activated.


This is something I have been mentioning for years.


At some point, enough is enough!
 

nerdly_dood

Member
Jun 15, 2010
2,312
Georgia
JohnMarcson said:
At this point my theory is that all colors are bright enough.... it's a matter of flash speed and limiting mixing of colors.
From my experience, blue lights are vastly less visible in the day than other colors. But I do agree that flash patterns and not mixing colors is important.
 

cory y

Member
May 21, 2010
1,614
I was driving down the road yesterday and on a long stretch of straight road... about a mile and a half down the road there was 2 dallas cops on a traffic stop, 2 impalas 1 with a wecan liberty the other with a mx7k.


On both vehicles the red portions of the bars were very visible from a mile out. But the blue was I would say about half as visible. But the amber halogen arrow of the mx was brighter than the reds of both.
 

tnems7

Member
May 21, 2010
407
USA Nashville Tennessee
Stendec,


Those studies reached back to 1998 to 2005 looking a crash data for emergency vehicles and what lighting was employed by the vehicles involved. I believe the more prevalent LED lighting would change the study results if and when it is repeated. Also, the need for barrier vehicles, traffic cones, and arrow boards was also cited. Many places, those are now SOP.


As to recommended colors, we have a lot of research already that a mix of colors is best, but particularly in the southeast, trying to get blue for use by agencies other than law enforcement would be very difficult.


And rather than a traffic advisor, I use one amber and one red light on the rear deck and then amber rear four way flashers on scene, rather than a traffic backer. But I am not law enforcement, I am rescue/EMS. Is it research based? No! Like most of the lighting we see by individuals on ELB, it is my preference and based on my opinion, because I am buying my own lights.


And, as meek as my LED warning lights might be, they do outshine the old Fireball 1 I was using forty years ago!
 

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