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August 01, 2007  |   Comments (7)   |   Post a comment

Roof Strobes Draw Crucial Attention

Strobes mounted on school bus roofs can help prevent collisions and illegal passbys — especially in inclement weather. More than a third of states require them.

by Thomas McMahon, Managing Editor


Being large and yellow, school buses are inherently some of the most noticeable vehicles on the road. But in certain conditions, such as inclement weather and low light, some added conspicuousness can help other motorists see the bus in time to stop safely, preventing collisions and illegal passbys.

The myriad lights required on school buses are key deterrents for these incidents. But one type of light not always found on school buses is the roof-mounted strobe.

These strobes are positioned on the longitudinal centerline of the roof, usually close to the rear but sometimes in the front. Their lenses are typically clear or amber, and the lights have an output of around 10 joules. Their intense flashing action can be another effective element in bolstering safety.

Attracting attention
Some operations, such as Henry County School System in McDonough, Ga., have roof-mounted strobes turned on whenever the bus is in transit. Beverly Skipper, director of transportation at Henry County, says that the frequency of accidents in which school buses are rear-ended by other vehicles has dropped significantly since the state included the strobes in its bus specifications.

"We still get those types of accidents, but they're not as common as they used to be," Skipper says.

The district has found the strobes to be particularly effective in foggy and smoky conditions. Skipper says that the relatively low cost of the units — about $100 per bus in Henry County's experience — is well worth the added safety they provide.

Skipper recommends that any school bus operation not already using the strobes look into them. "It is worth installing them, because they do save lives," she says.

Iowa Park (Texas) Consolidated Independent School District requires its bus drivers to run their strobes at all times. The policy was adopted at the request of the local police department.

Kent Chapman, who handles fleet maintenance and dispatching at the district, says the strobes' benefit is clear. "It's an attention-getter — it makes [motorists] aware that there's a vehicle ahead that is probably traveling slowly," he says.

Donna Sullivan, assistant director of transportation at Manhattan-Ogden (Kan.) Public Schools, says that her operation quickly saw the benefit of roof strobes after equipping their fleet a few years ago. "We always keep track of stop-arm violations, and there was a significant drop after we put strobe lights on the buses," Sullivan says.

State by state
Regulations on roof-mounted strobes vary by state. In a survey of state directors of pupil transportation, SBF found that at least 17 states require the strobes on school buses (42 of the 50 states responded). The other 25 states that responded allow the strobes but don't require them.

Several of the states that require the strobes said that they began doing so within the past 15 years.

Mike Simmons, state director in Arkansas, says that the state's School Bus Safety Act of 1995 mandated that all school buses be equipped with a strobe as well as a crossing arm beginning July 1, 1997.

In other states, buses manufactured after a certain date must have a strobe. Delaware, for example, requires buses built after Jan. 1, 2001, to be equipped with a strobe.

Ron Love, state director in Delaware, says that the state decided to follow the strobe usage recommended by the 2000 National School Transportation Specifications and Procedures. The specs call for a white strobe to be wired to activate "when the amber alternately flashing signal lamps are activated, continuing through the full loading or unloading cycle, with an override switch to allow activation of the strobe lamp anytime for use in inclement weather." A pilot lamp in the driver's area indicates when the strobe is in use.

State specs often call for the strobes to be mounted on the longitudinal centerline in the rear third of the roof, but some states allow them near the front as well. Mississippi gives bus operators the option of installing a strobe above the driver's head area or near the rear.

Maine allows both forward and rear roof-mounted strobes, and they can be white or red as long as both are the same color. Some other states allow or specify amber for strobe color.

Though all of the states responding to SBF's survey allow the strobes, some have restrictions on when they can be used. In California, school bus drivers may only use the strobes when visibility is reduced to 500 feet or less due to such atmospheric conditions as fog, rain, snow, smoke or dust. The conditions do not include the darkness between a half-hour after sunset and a half-hour before sunrise.

In Michigan, school bus drivers may only use the strobes during inclement weather, loading or unloading of passengers, hindrance in visibility of the bus or, unlike California, a half-hour after sunset until a half-hour before sunrise.

Some states that don't require the strobes still see widespread use of them. For instance, Indiana doesn't have a strobe mandate, but state director Pete Baxter says that a survey in 2000 found that about 78 percent of the state's school buses were equipped with them.

The strobes are also not required in New York, but state director Marion Edick says that the purchase of them is an aidable expense. "Our program office opinion [of the strobes] is favorable," Edick says. "They are especially good in fog and winter storms."

Strobe specifics
A number of companies supply roof-mounted strobes for school bus applications.

Aeroflash Signal has been making strobes for school buses since the early 1980s. Currently, the low-profile M420 and the M100 are the company's more popular offerings for pupil transporters. Most opt for a 10-joule output, and some order optional branch guards for added protection.

Heavy Duty Bus Parts offers several strobe models from different manufacturers, but its most popular unit is its own HDBP model. The 12-volt, self-contained strobe is about 4-1/2 inches tall and 6-3/4 inches in diameter. The strobe can be set to double- or quad-flash. It double-flashes 40 times per minute.

SoundOff Signal supplies school bus operators with strobes that are designed for heavy-duty use. Most states specify a low-profile, 4-inch dome with a branch guard and a clear lens for white light output when ordering from SoundOff. The company's most commonly used model is the 3107LCC, but the 7202LCC is often chosen for maximum light output.

Specialty Manufacturing supplies low- and high-profile strobes in energy levels ranging from 10 to 18 joules. They are fully encapsulated for protection against weather conditions, and their rugged aluminum bases provide vibration resistance and heat dissipation. The strobes single- or double-flash and are available with amber, clear, red, blue or green lenses.

Weldon Technologies offers its 7150 series 360-degree strobe. The unit is available in a low- or high-profile size (4.8 or 6.7 inches). The strobe functions in 12 to 14 volts. Its base, which can be die cast or polycarbonate, mounts with three screws. Lenses are available in red, amber or clear.


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As someone who is in the school bus industry I can verify that accidents have reduced since using strobe lights. How ridiculous to suggest NOT using strobe lights in poor weather. Should all vehicles with any sort of flashing lights be told not use them in poor weather? So snow plows wouldn't use them? How idiotic! Should all billboards be taken down and advertising signs that have any sort of animation or lights be taken down? This is the most ridiculous argument everyone! The fact is that the strobe lights notify people that there are students on the bus. Most school boards recommend only using it during this time or in poor weather. It allows motorists to be aware of the fact that the bus has students on it so it may be stopping, slowing down etc. If people are having seizures due to strobe lights then they need to have their licences taken away. If you're not healthy enough to drive - or fly, then DON'T!

Jessica    |    Nov 10, 2015 01:40 PM

Strobes have reduced the amount of bus related accidents,especially in inclement weather.They are supposed to distract you,so as to get your attention I'm sorry but these comments about white strobes are incorrect,people are commenting without any knowledge about them I haven't heard a single case of a elliptic ,having a seizure behind a school bus with a white strobe.Accidents involving school buses,especially in inclement weather have fallen sharply,as far as headaches [go see a doctor,its not the strobe,have your eyes checked],a distraction ?[yes its supposed to get your attention.Duh.People love to complain,lets just ,make all lights illegal,good luck on your night time flight or driving in the dark.Strobe lights save lives,especially in bad weather..PERIOD

Thomas lewis    |    Mar 30, 2015 07:34 AM

I AGREE with Mr. Lewis above.. Those STROBES are DANGEROUS. They are a major distraction if you find yourself stuck behind a bus. In buildings fire alarm strobes ALL HAVE TO BE Synchronized to flash at the same time. If you are behind 2 buses on a 4 lane, they may cause seizure. I will tell you here and now If I have to do 90 MHR to pass a bus, I DO IT ! That's probably why rear end accidents went down .. Because NOBODY LIKES THOSE STROBES AND PASS THE BUS !

Dave Puditinu    |    Jun 07, 2014 09:02 PM

I got stuck in a traffic jam on the highway two months ago two cars behind a school bus with a strobe light on it. We were sitting still in traffic for at least three minutes and I was trapped behind the bus for at least another three or four until I could get to my exit. When I got home, I had such a bad headache from the strobe I actually had to lie down. I didn't dare take any aspirin until my stomach settled because it would have come back up immediately. It was an awful experience.

Taquoshi    |    Mar 11, 2014 08:11 PM

the dangers of strobes,nonsense,every person I spoke to has said,it does not bother them and it does get their attention.Any product can be abused,misused and except for aircraft,daylight operational only.It saves lives,period.

thomas lewis    |    Nov 08, 2013 08:32 AM

Motorcycle accidents could be reduced by the addition of a daylight only visible white strobe,the headlight on does nothing.

thomas lewis    |    Nov 08, 2013 08:27 AM

Regarding the DANGERS OF STROBES: Folks, these strobes are far more dangerous than they are good. As a pilot, one must turn off strobes in fog, rain, snow due to vertigo. This is the same on the ground as it is in the air. Why would you wish to "blind" drivers following a bus, particularly over a long distance. These strobes SHOULD BE OUTLAWED and NOT USED. Wikipedia: Flicker vertigo is "an imbalance in brain-cell activity caused by exposure to low-frequency flickering (or flashing) of a relatively bright light" [1] The strobe light effect causes persons who are vulnerable to flicker vertigo to become disoriented, lose control of the aircraft (Vehicle). Due to the intensity of the brilliant white light source, the intended use for strobes is during daylight hours of operation. Strobes should really not be used in inclement weather, in the clouds or on the ground as this can cause flicker vertigo. BUT THIS IS WHEN MOST BUS DRIVERS USE THE STROBES ! THE WORST TIME TO HAVE THEM ON!!!! Aviation FAR 91.209—You must use position and anti-collision lights between sunset and sunrise, but this regulation says you can turn off the anti-collision lights for safety, such as when flying in precipitation. Distractions and problems can result from a flickering light in the cockpit, anticollision light, strobe lights, or other aircraft lights and can cause flicker vertigo. If continuous, the possible physical reactions can be nausea, dizziness, grogginess, unconsciousness, headaches, or confusion. The pilot should try to eliminate any light source causing blinking or flickering problems in the cockpit. Flicker vertigo has been reported as the cause of some aviation accidents. Twenty two percent of helicopter pilots and 30 percent of airplane pilots said flight through fog with a rotating beacon had caused flickering light in the cockpit. At night, anti-collision lights reflecting off the clouds can produce the effect. Flicker vertigo can develop when vi

GFREE    |    Jan 31, 2012 05:42 AM

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