# Can A Car's Airbag Be Activated By A Pedestrian Kicking The Front Of The Car? **URL:** \ **Category:** Factual Questions\ **Created:** [January 2, 2024, 5:33pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504 "2024-01-02T17:33:15Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![HeyHomie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heyhomie/32/207_2.png) [@HeyHomie](https://boards.straightdope.com/u/HeyHomie)\ **Post date:** [January 2, 2024, 5:33pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/1 "2024-01-02T17:33:15Z")
A brief (as in, 5-10 seconds) ad for some streaming series appears in my ads from time to time. It shows a man sitting in a car and a pedestrian angrily approaches it. The pedestrian then kicks the car in _just the right place_, and the airbag deploys. Fade to title card. Is this even remotely possible? \*If anyone is wondering, I _think_ the show is _Reacher_, and I _think_ it’s on Amazon Prime. ---
**Author:** ![Mikkel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikkel/32/13151_2.png) [@Mikkel](https://boards.straightdope.com/u/Mikkel)\ **Post date:** [January 2, 2024, 5:39pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/2 "2024-01-02T17:39:39Z")
Is it this one? [![](https://img.youtube.com/vi/BmH_eIhHLX8/hqdefault.jpg "Old lady triggers airbag IKEA") ](https://www.youtube.com/watch?v=BmH_eIhHLX8) No, I don’t think it’s possible ---
**Author:** ![kayaker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kayaker/32/441_2.png) [@kayaker](https://boards.straightdope.com/u/kayaker)\ **Post date:** [January 2, 2024, 5:39pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/3 "2024-01-02T17:39:58Z")
The show is definitely **Reacher.** ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [January 2, 2024, 5:45pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/4 "2024-01-02T17:45:32Z")
> **[Alan Ritchson Airbag Scene - The Reacher #clips #netflix #shorts](https://www.youtube.com/watch?v=JoVEHeabrHg%2F)** ---
**Author:** ![Mikkel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikkel/32/13151_2.png) [@Mikkel](https://boards.straightdope.com/u/Mikkel)\ **Post date:** [January 2, 2024, 5:55pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/5 "2024-01-02T17:55:43Z")
I see, isn’t the Ikea one funnier? Why does he kick the car? ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [January 2, 2024, 5:58pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/6 "2024-01-02T17:58:25Z")
The guy in the car was following him, of course, and to get the drop on him, Reacher kicks the car, sets off the airbag, and uses the ensuing confusion to get started with the fisticuffs. ---
**Author:** ![DavidNRockies](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/davidnrockies/32/6279_2.png) [@DavidNRockies](https://boards.straightdope.com/u/DavidNRockies)\ **Post date:** [January 2, 2024, 6:01pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/7 "2024-01-02T18:01:58Z")
Answer scabbed from another site: > [@](#): > > No, at least not modern airbags. > > Since the activation depends on several sensors switching at the same time, and they [typically need that the whole car is accelerated with 3-5g](https://www.hella.com/techworld/uk/Technical/Car-electronics-and-electrics/Car-airbag-system-3083/#) including the corresponding deformation of the frame, no force a human can produce will suffice due to the inertia of the immense mass of the car. Kicking the steering wheel won’t do much. > > Just to put this into perspective, in order to accelerate a very light car of one metric ton so that the sensors go off, you’d need to produce at a minimum **29.34 kN** (1000 kg, 3g acceleration) while a very powerful kick [seems to typically top out at about **2 kN**](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5571909/). That doesn’t even count in roll resistance and that most of the force won’t go into an actual acceleration of the car but rather into deformation of the front (or back). > > Long story short, a kick can produce not even a tenth of the force needed to accelerate a very small car so that its airbags go off. [**SOURCE**](https://martialarts.stackexchange.com/questions/13337/activate-a-cars-airbag-with-a-kick) My spidey sense says this is a pretty credible answer. ---
**Author:** ![Mikkel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mikkel/32/13151_2.png) [@Mikkel](https://boards.straightdope.com/u/Mikkel)\ **Post date:** [January 2, 2024, 6:04pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/8 "2024-01-02T18:04:42Z")
I still don’t think it’s possible. I have once triggered the seatbelt tightener in an old Mercedes by going over a bump too fast, but the airbag stayed intact. That was much more violent than I think even a professional football player could kick. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [January 2, 2024, 6:14pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/9 "2024-01-02T18:14:57Z")
> [@HeyHomie](#): > > Is this even remotely possible? The sensors that trigger airbag deployment measure deceleration of the chassis. Airbag deployment imparts its own risk of injury, so it’s important to for the system to ignore signals that don’t correspond to the onset of an actual dangerous collision. A kick to the bumper isn’t going to do it: the resulting chassis decel won’t be strong enough or long-lasting enough for the system to interpret it as being a collision worthy of airbag deployment. **[This video](https://www.youtube.com/watch?v=NPfGR-31AkU)** shows where the front impact sensors are on a BMW (at 1:42) and on a Chevy (at 3:16). In either case, they’re not in the bumper, so kicking the bumper will barely register on these sensors. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [January 4, 2024, 10:19am UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/10 "2024-01-04T10:19:25Z")
Airbags are triggered by multiple redundant sensors, so no. ---
**Author:** ![pullin](https://avatars.discourse-cdn.com/v4/letter/p/c57346/32.png) [@pullin](https://boards.straightdope.com/u/pullin)\ **Post date:** [January 4, 2024, 10:50am UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/11 "2024-01-04T10:50:27Z")
A related question: Could a car’s airbag be triggered by another vehicle reversing into it (at high enough speed)? Would the seat belts detect this as a “deceleration” and lock up? Just curious. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [January 4, 2024, 12:13pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/12 "2024-01-04T12:13:06Z")
> [@pullin](#): > > A related question: Could a car’s airbag be triggered by another vehicle reversing into it (at high enough speed)? Would the seat belts detect this as a “deceleration” and lock up? “Deceleration” is just acceleration in a rearward direction. For the vehicle and its occupants, deceleration of a forward-moving car due to collision with a stationary object has the same effects as rearward acceleration of a stationary car due to collision with a moving object. If I’m stopped at an intersection and an oncoming car crosses the line and head-ons in to me, I definitely want my airbag going off. Differentiating between the two scenarios (me-in-motion colliding with a stopped object, and object-in-motion colliding with a stopped me) would require that the system deliberate examine the vehicle’s speed at the moment of impact, and I can’t imagine why the designers would design it to operate that way. Note also that while older seatbelts had a simple mechanism that stopped the reel from paying out belt when a certain belt velocity was reached, newer systems trigger a pyrotechnic device that actively takes up several inches of slack in the belt, as seen in this video at the 2:00 mark: [![](https://img.youtube.com/vi/6phdJWRi_vw/maxresdefault.jpg "Seatbelt Pretensioner in Super Slow Mo - The Slow Mo Guys") ](https://www.youtube.com/watch?v=6phdJWRi_vw) ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [January 4, 2024, 2:38pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/13 "2024-01-04T14:38:11Z")
My dad mentioned once upon a time that there was a problem in NJ - joyriders would steal a car, drive around and then if they found a parked occupied police cruiser, ram it from behind hard enough to set off the airbags in the cruiser. I assume this was back when cheaper, older cars had no airbags, or the joyriders would have an airbag problem too. Or perhaps this was a urban legend he’d heard along the lines of the “gang initiation - flash your lights at a car with no headlights and they shoot you”. Roughly how fast would a car need to be going to set of airbags in a collision? ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [January 4, 2024, 2:48pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/14 "2024-01-04T14:48:59Z")
> [@kayaker](#): > > The show is definitely **Reacher.** Yup. And for context for those who haven’t seen it, Reacher is portrayed to be a comically enormous man of just gargantuan strength. Not in a comic book supernatural way, but large enough that it’s a continual plot point throughout the series. Most of his feats of strength are absurdly exaggerated, but it’s a fun show. ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [January 4, 2024, 2:55pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/15 "2024-01-04T14:55:35Z")
> [@md-2000](#): > > Roughly how fast would a car need to be going to set of airbags in a collision? Between 10 and 16 MPH, depending on whether the occupent is belted in. Side airbags have slightly different algorithms. > **[Airbags](https://www.iihs.org/topics/airbags)** > > Information from IIHS-HLDI on airbags ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [January 4, 2024, 3:13pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/16 "2024-01-04T15:13:56Z")
> [@Munch](#): > > Yup. And for context for those who haven’t seen it, Reacher is portrayed to be a comically enormous man of just gargantuan strength. Not in a comic book supernatural way, but large enough that it’s a continual plot point throughout the series. > > Most of his feats of strength are absurdly exaggerated, but it’s a fun show. Yes. One of the funniest aspects of the Reacher saga is that his larger size (6’4"?) and musculature is specifically mentioned frequently in the books, it’s often a plot point…yet in the original movies made, he was cast as the midget Tom Cruise. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [January 4, 2024, 5:59pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/17 "2024-01-04T17:59:59Z")
**Moderator Note** > [@md-2000](#): > > midget Tom Cruise The word “midget” is considered by many to be offensive these days. Let’s try to avoid it. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [January 4, 2024, 6:02pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/18 "2024-01-04T18:02:27Z")
> [@md-2000](#): > > My dad mentioned once upon a time that there was a problem in NJ - joyriders would steal a car, drive around and then if they found a parked occupied police cruiser, ram it from behind hard enough to set off the airbags in the cruiser. I assume this was back when cheaper, older cars had no airbags, or the joyriders would have an airbag problem too. > > Or perhaps this was a urban legend he’d heard along the lines of the “gang initiation - flash your lights at a car with no headlights and they shoot you”. Sounds like urban legend. If the car is parked/shut down, the airbags shouldn’t deploy. But if it’s an **occupied** police cruiser, as you described, then the miscreants are hoping they will be able to outrun the cop (on foot, if they manage to disable their own car) right after having outed themselves as car thieves. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [January 4, 2024, 6:08pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/19 "2024-01-04T18:08:09Z")
The airbags deploying in and of themselves don’t render a car undrivable. It’s less convenient to drive with the bags hanging around, but not impossible as such. To be sure, if a car crashes hard enough to deploy the airbags the crash certainly _might_ render it undriveable, or render whatever other car(s) it collided with undriveable. But overall I’d rate this as urban legend. It you want to disable a car that’s not the one you’re driving, best to crash into its front, not its rear. Radiators and engines and front fenders can take far less damage than the read end before the car is undrivable. There’s a reason demolition derby drivers are mostly driving in reverse, using the ass end of their car as a durable battering ram against the other cars not-durable front quarters and front ends. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [January 4, 2024, 6:11pm UTC](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504/20 "2024-01-04T18:11:43Z")
> [@md-2000](#): > > Yes. One of the funniest aspects of the Reacher saga is that his larger size (6’4"?) and musculature is specifically mentioned frequently in the books, it’s often a plot point…yet in the original movies made, he was cast as the midget Tom Cruise. - Those movies should have been “son of Reacher”. Petite mom to explain the size difference and a cameo by Dolph Lundgren as “elder Reacher”. [Next page](https://boards.straightdope.com/t/can-a-cars-airbag-be-activated-by-a-pedestrian-kicking-the-front-of-the-car/995504.md?page=2)