Home | Authors | Adams | Are “High and Slow” Warning Lights Feasible?

Are “High and Slow” Warning Lights Feasible?

By Bill Adams

Discussions about dimming fire apparatus warning lights have abated somewhat but haven’t completely disappeared. They definitely haven’t reached the point of honest debate where deliberation and examination of facts may result in a conclusion acceptable to all parties. Perhaps if the topic is ignored, it will go away.

Tom Shand provided this photo of a 1958 Seagrave pumper with fixed stationary red lights mounted through the front corner posts. Today’s full light bar aficionados might acquiesce in having lights similarly mounted on new rigs.

Some are apprehensive nothing will be accomplished until just before proposed changes are due for the next revision of National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus. Equally foreboding is, at that time, there will be another rush to expedite changes to the standard based on emotional reactions “to get something done” rather than as a result of unhurried testing, analysis, and unbiased investigation. Oh well, what is is.

NFPA 1901 criteria for warning lights include two modes of operation: calling for the right-of-way (responding) and blocking the right-of-way (stopped). This article does NOT address warning lights when responding. However, some comments made could be applicable to that mode. It addresses warning lights used in the blocking-the-right-of-way mode.

Harvey Eckart supplied these two delivery photos (2-3) of older Mack apparatus with high mounted red flashers.

The fire service and lighting industry should be mindful the motoring public has no clue or care about what NFPA 1901 is or says. It doesn’t have to. Most have probably never heard of it. Motorists are obligated by law to respond to certain colors of warning lights designated by their state—or the Federal government. I don’t believe states teach motorists how to react to flash rates or whether lights are rotating, flashing, oscillating, pulsing, or throbbing.

Harvey Eckart supplied these two delivery photos (2-3) of older Mack apparatus with high mounted red flashers.

Warning lights on emergency vehicles are “sending a signal” to motorists to respond and to do whatever the motorists were taught when taking a test to receive an operator’s license. They probably had to acknowledge it in writing! How motorists respond or react to warning lights is mandated by laws—not by the NFPA. They might be required to stop or yield right of way, or pull to the right and stop, etc. NFPA 1901 has nothing to do with it.

Stupid, inattentive, medically impaired, and drug- or alcohol-impaired drivers might not pay attention to the rules and regulations of the road let alone warning lights.

I believe the only nationwide “accepted and expected” response to warning lights is when they are displayed on school buses and at railroad crossings. Elevated alternating flashing red lights mean STOP. There’s either a stopped school bus in front of you or a train is, or will be within seconds, crossing the road in front you. That’s pretty much standard from the Pacific to the Atlantic.

An elevated amber light or alternating flashing amber lights are generally accepted to mean SLOW DOWN and/or USE CAUTION. Flashing amber lights on a school bus means be prepared to stop because the red lights are coming on soon. That also is a nationwide norm. When an amber light or lights are displayed on vehicles other than school buses, the general consensus is to use caution because there’s something (that’s possibly very big) that is slowing down or has stopped in front of you.

The analogy is similar to amber traffic light signals. A single amber flashing traffic light means caution—the other guy might be exercising the right of way. Or, if it’s a multilight traffic signal, amber means get ready to stop because the red light is coming on next.

The Penfield, NY Fire Company provided this photo of one of their former rigs—a 1971 Young Crusader. It featured two large red flashers mounted each side above the windshield.

Proponents of using multiple forward facing warning lights whether they are spinning, flashing, oscillating, or whatever should not panic. Use them and all the strobes, Roto-Rays, Mars figure 8 lights, and flashing headlights you want when responding—providing, of course, they don’t obscure directional lights and blind or distract motorists. This concept for high and slow warning lights is intended for use in the blocking-the-right-of-way mode. The rig is stopped, and you don’t want anyone to ram it or the firefighters working around it. Hopefully the public is aware that is what the warning lights mean. They might if the light color(s) and flash pattern(s) are similar to school buses and railroad crossings.

Years ago, many rigs featured red warning lights—about 6-inches in diameter—one each side above the windshield. Most rigs had similar lights facing the rear. Some flashed simultaneously, however, just like school buses and railroad crossing lights, many were alternating flashing. Did the fire service copy the school buses and the railroads or was it vice versa?

The high and slow concept still works today for school buses and railroads. Could it be still feasible for fire apparatus in the blocking mode? I am not proposing going back to the identical warning lights of 50 years ago. The concept might be worth investigating.

Somewhere within the bowels (my term) of Federal Motor Vehicle Safety Standards (FMVSS) are requirements for school bus warning lights. Discounting the recent swing-out arms with warning lights, the requirement for the upper lights is, I believe, each lamp lens must be 19 -square inches and alternately flash from 60 to 120 cycles per minute. As a reference, the area of a 5-inch round light lens is 19.6-square inches, and the 6-inch size is 28.27 square inches.

The United States Department of Transportation Federal Highway Administration publishes the Highway-Rail Crossing Handbook. It says new red flashing lights at rail crossings must be 12-inches in diameter, with a 35- to 65-flash rate per minute. Just like a school bus—the lights are large enough to be “color visible” and are slow flashing, and motorists all over the country know what they mean.

Author’s photo of a 1940 Mack with similar high flashers. The fender mounted combination light and siren had a slow flashing light with over 36-square inches of “red” facing forward. There is no recommendation to go back to warning lights of yesteryear however a similar size light or lights, whether they be LED or halogen flush or surface mounted may have merit today. You can see it, recognize it and hopefully will stop or get out of the way!

Railroad crossing lights must be visible at a certain distance. If there’s such a requirement for school bus warning lights, it’s probably in FMVSS Standard No. 108, SAE School Bus Warning Lamp J887. Some European countries mandate warning lights on emergency vehicles must be “recognizable” at a certain distance from the vehicle “in bright sunlight.” Should NFPA 1901 require something similar for warning lights rather than requiring a candela/seconds per minute requirement that most firefighters don’t understand?

Table in NFPA 1901 shows the Minimum Optical Power Requirements for Large Apparatus. It is an interesting read. Lower warning light power requirements in the blocking mode are only 15% of the upper lights in the responding mode. Could today’s minimum requirements be changed to the maximum power requirement for all warning lights when blocking the right of way?

Would it be blasphemous for the NFPA to require ALL warning lights in the blocking-the-right-of-way mode to be amber and flash slowly? Is there a way to address warning lights, especially at night, that reflects common sense and is not expensive to implement? LED lights shouldn’t be so bright they distract oncoming motorists or blind the pilots of low-flying aircraft. One light manufacturer says the amount of current flowing across an LED chip determines how bright the light is.

Perhaps the manufacturers should be challenged: “Make an LED warning light that is not distracting to motorists, yet meets NFPA 1901 and does not have to be dimmed or regulated at night.”

BILL ADAMS is a member of the Fire Apparatus & Emergency Equipment Editorial Advisory Board, a former fire apparatus salesman, and a past chief of the East Rochester (NY) Fire Department. He has 50 years of experience in the volunteer fire service.


  1. Our apparatus ALL the lights above the windshield go black when parked. The rear light are on a control so we leave them on when on a controlled access highway and ALL the forwards light are of except the 4 way flasher. When at scene with the road blocked we shut them ALL off and don’t distract or blind the crew. We have done this for over 20 years…..One clear and red bright warning light between the headlights at the bottom of the windshield will be seen by the operator in front of you….

  2. With today’s technology LED lights can be configured so that they can flash as different colors from the same bulb. Combining that with the ability to change the intensity, there should be significant ways to provide adequate and effective warning lighting for all conditions.

    In addition, many departments are now mounting various kinds of warning devices in the center of the grill. These are extremely effective in heavy traffic conditions because the roof mounted lights quite often are not visible to the drivers immediately in front of the vehicle.

  3. Recently we changed the warning lights on our heavy squad from incandescent to LEDs that flash like an old time incandescent as opposed to the multiple ultra bright LEDs that flash so fast and are overpowering bright. The result is a vehicle that can be well seen in all circumstances with causing the oncoming drivers to become instantly blind by the intense lighting. It is almost painful to walk up to our standing ambulance when they have all the lights on, let alone work in that environment. In my opinion, more is not always better and we need to get away from that mentality ASAP.

  4. In my nearly 40 years in the fire service I worked a lot on interstate highways. I have had my share of close calls while apparatus was stationary working an incident. In the last third of my career I was a strong proponent of “purposeful” on scene lighting. That is to say, lighting that is clearly giving an indication of what oncoming traffic is to do. Whatever happens to the standard should be two fold in that it should be purposeful in intention and understood by someone who is entirely unfamiliar with emergency vehicle lighting. Throwing more light at oncoming drivers seems to be the trend. It doesn’t matter if it is a wrecker, DPW truck, or contractor in their own pickup truck who does snow plowing. The intensity in the number and brightness of lights is an epidemic. Motorists are being dazzled, blinded and confused. The fix, in my opinion, not only is purpose but toning down across the boards. If you come across a crash on a highway, it can be an incredible barrage of lights for the motorist to decipher. It is a small wonder motorist mishaps are a problem. I believe the answer is a cross jurisdictional coordinated approach to on scene lighting. That is why school bus and railroad warnings work as well as they do.

  5. I’ve said it before and I’ll say it again, the solution is not going to be fashioned from the number of lights on a vehicle or their intensity. How many emergency vehicles do you have on a scene of crash? We at minimum have an engine, a rescue, two police cars, at least one ambulance and some pov’s; that’s five departmental vehicles if they all have “high and slow” won’t mean anything, they’ll still be a bunch of lights that will still cause the monitoring public to remain confused….. because the monitoring public needs to be educated, a basic, fundamental process that had been eliminated in our schools, so it’s no wonder we can’t educate new drivers. And what they do teach them is directly opposed to state law requirements (in Michigan state law requires motorists to pull to the right and stop, driver’s education instructors tell their students to just stop anywhere). When the educators aren’t knowledgeable, they can’t correctly teach. Shoot our MDOT engineers can’t even correctly post road narrowing signs properly, the state law requires motorists to drive in the right lane, but then they post signs saying merge left. It’s no wonder the motoring public is confused. How about this …. if you’re blinded by the lights and you don’t know what to do — STOP, creep up slowly watching for personnel to direct you, or simply take another route, it might take up some of the motorist’s time, but someone else is having a much worse day than you are by having to detour or wait.


Check Also

Darley Announces Availability of Smart Bottle®

Itasca, IL, July 13, 2021 – Darley, in partnership with KRW, has ...