In many states of the USA, school buses are fitted with a "roof-mounted strobe".

In some states, they are required by law:

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 some states they are not required, but often found:

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 local states also vary about the conditions under which they may 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.

Safety Claims

There are claims that these devices improve safety:

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.

Is there good evidence to support the claim that roof-mounted strobes on school buses improve safety?

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    I've made a significant edit to this question to bring it inline with community standards. If there is a lot more context than usual, it is because I have never seen or heard of these things before, and I needed it explained to me!
    – Oddthinking
    Commented Apr 19, 2016 at 15:24
  • @Oddthinking Fine with the edits, thank you. I guess my point is that people seem to come up with ideas that they think will "help" but they either have no discernible effect, or it is not a worthwhile benefit compared to the problems it causes. Because you cannot prove harm, everyone gets to weigh in with their improvement ideas and cannot be gainsaid. I think this is just dumb. Individual cases of benefit are not what we base our laws and policy on, or else there would have to be a set of books for every citizen, because one man's meat is another man's poison, often quite literally.
    – user29285
    Commented Apr 19, 2016 at 23:35
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    Sure, but that is all your political opinion, which is off-topic.
    – Oddthinking
    Commented Apr 20, 2016 at 0:57
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    @nocomprende - I lurk here more than post, so I may be wrong, but: You say 'kill truly bad ideas', but applying a 'good' or 'bad' label is an opinion. As per the Tour, (emphasis mine): "Skeptics is a question and answer site for applying scientific skepticism... ...we're working together to build a library of detailed answers challenging unreferenced notable claims, pseudoscience and biased results." I would say that Skeptics.SE tries to remain neutral when approaching claims, only drawing conclusions from the facts presented.
    – Robotnik
    Commented Apr 20, 2016 at 4:32
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    Do the strobes increase risk to other road users, by getting the drivers to look at the school buses to much? Commented Apr 20, 2016 at 11:40


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