EMERGENCY VEHICLE SIRENS, lights, useage, etc.

[Robert Gift]

Just saw a private ambulance with a GREEN forward-facing light in the middle of the light bar.

I asked if they were IC (Incident Command)
They answered, No.

They are trying GREEN lights to stand out better.

Red blends in with brake lights, signs and traffic signals.
White blends with headlights and many other lights.
Blue blends in with few things, but is not very bright and not well seen during daylight.
Yellow stands out and is bright.
White is brightest.

[q2bman]

I remember accident scenes where i was first on scene. My lights were effective a little but when the mass of fire trucks ems and police were on scene people crawled through at a slow speed. I think the more lights the better because people are aware it is something more serious than a traffic stop. A car with just hazzards is way down on the list of concerns for most motorists. A vehicle with a lightbar is better, a million flashing lights and people slow down to assess the situation and figure out what to do.


I had a nice vacation one year to California. On the way back I ran accross an accident. A semi had its hazzards on in the shoulder at about 3am. Drivers flew past him. I slowed way down to see if I could help. I activated my personal strobes, Six white lights to the rear, and stopped in the lane to protect the cars and debris. Turned out to be a tripple fatality accident. The scene was much better but still unsafe. People slowed more so than for the hazzards but still flew through. It was only when about six troopers, two fire rigs, and an ambulance arrived that people slowed way down to a crawl.

[Jim_Ferer]

Four-ways aren't good enough and a well-lit scene is good, but there is such a thing as too much. The brightness of some light setups can make it impossible to see other hazards in the road and shock the eye to boot.

[StonedChipmunk]

Saw many, many emergency vehicles on a drive from a clay trap shooting range back to school today. Strobes, LED's, rotating, all sorts of different colors. All working (duh).
Must have been some big emergency down here.
Anyways, my analysis concluded with these results:

Color ranking during broad daylight:
Yellow
Green
Blue
Red (light was shining on red causing it to not show as well)
White (too bright today to see it at ALL)

Light type visibility during broad daylight:
Stobe
Rotating
LED
(Note: I say LED worst because the lightbar was one of those superthin ones... couldn't see it until actually next to it).

I also think that the flash pattern efficiency depends on the speed of the vehicle. If the vehicle is moving quickly, a barrage of strobes won't do much effect, since it will seem just like glare or something. On the other hand, synchronized strobes are less efficient while at a standstill, because a barrage of strobes catches the eye better because of the brightness, while synchronized strobes dont do much better.

EDIT: Note that I'm 14 years old, so my eyesight is better than most.

[loudmouth]

strobes are best at night they are quick flashes to cach the eye.
Rotors are best for day light due to there lag time.
LEDs are a littel bit of both worlds you can delay the flash exsposer to allow the eye to cahch the light better. and the amount of patterns keep the eyes for getting hipnotized to the lights. Plus they save on battery power and save some gas too since they are thiner. unlike the rotors which can be bulker.
Yellow is the hardest collor to see during the day if its a strobe
red is more eye cachin during the day
blue isnt the best in the day light.