Automatic Hazard Lights?

Question

Automatic Hazard Lights?

IRstuff (Aerospace)

(OP)

29 Nov 21 17:42

I was watching this video from a roundabout in Milwaukee, which I guess is their version of the low bridge collision video site: https://www.youtube.com/watch?v=Vmi8AjlNDlY

The hazard lights come on pretty quickly after the car does its thing, but did they automatically come on because of the collision, or did the presumably intoxicated driver had such presence of mind to turn on the hazard lights, but not enough to even make it into the roundabout in the first place? Inquiring minds want to know; but don't want to test their cars to find out.

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3DDave (Aerospace) · Answer 1 · 2021-11-29 19:30:24

I've seen that a lot of crash videos and believe it is automatic under many circumstances - too often for dazed or confused drivers to manage. More than once have I had a lengthy search of a dashboard to figure out where the User Interface guys hid what should be a prominent button.

I'd give a 100% likelihood of being linked to airbag deployment.

However - I see this for Smart (brand) cars:

Activating the hazard warning flasher
after an emergency braking maneuver
If you bring the vehicle to a complete stop
by strongly braking at a speed of more than
43 mph (70 km/h), the hazard warning
flasher automatically comes on as soon as
the vehicle is at a standstill.

As far as I can tell it's not required nor prohibited in the USA so I suspect makers are adding this

BrianPetersen (Mechanical) · Answer 2 · 2021-11-29 20:41:10

Can't tell in the video what the car was. Lots of european cars automatically turn on their hazard-warning lamps after an "event". I'm not sure what the criteria are for triggering them.

CWB1 (Mechanical) · Answer 3 · 2021-12-01 15:58:06

Yes, they appear to come on at the moment of impact before the vehicle even stopped moving. On modern vehicles there are both physical and software triggers for these events, physical sensors being on the body and also in some of the electronic modules.

Compositepro (Chemical) · Answer 4 · 2021-12-01 16:58:02

Seems a good feature, so why not? Fuel pumps are also cut off automatically in minor collisions. How did I learn that?

IRstuff (Aerospace) · Answer 5 · 2021-12-01 19:36:54

Thanks, one less thing for me to remember after a collision

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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Belanger (Automotive) · Answer 6 · 2021-12-30 15:43:22

Actually had this happen to me last week! A stupid deer jumped in front of my vehicle (on the freeway, at night) and smashed the front end. I'm fine, but the airbags deployed and the hazard lights went on. After the tow truck arrived, I turned them off using the normal switch.

IRstuff (Aerospace) · Answer 7 · 2021-12-30 17:10:07

Glad to hear that everything in the car's safety system appears to have worked as intended.

TTFN (ta ta for now)
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Automatic Hazard Lights?