Couple of days ago my car was parked in front of another car. Given that I needed more space to get out of the parking spot, I drove backwards and hit the front of the car behind me. I got out of the car and saw no visible damage to both vehicles, apart from the registration plate of the other car being slightly bent. I assume the crash happened at around 2-5mph. The car was no more than 2 meters behind me, so there was no space to accelerate much and of course I didn't press the gas pedal hard. I also hit the brake just before the collision, so I assume the speed was really low.

Since it was late and dark and I was in a hurry and didn't see any damage, I drove off. I also didn't have a pen to leave a note. The next day I realised that this was wrong and felt guilty about it.

So my question is whether it is possible to have caused some damage, given that there were no visible dents apart from the bent registration plate? More specifically, is it possible to have affected the safety of the car?

My car is a BMW 3 2007 sedan, and the other car was an Opel of similar size (probably an Astra) produced in about the same year.

  • Welcome to Motor Vehicle Maintenance & Repair! Commented May 30, 2018 at 23:37

2 Answers 2


Based on your description of the accident, I don't think it was severe enough to create non-visible damage or affect the safety of your car or the other car involved.

Modern vehicles have crash beams behind the bumpers which are designed to protect the chassis and safety of the vehicle in low speed accidents, and can sometimes protect the chassis of the vehicle and its safety systems in accidents that totally destroy the bumper cover.

I can confidently say that both cars are totally fine (other than a slightly bent number plate).

You might be interested in reading the regulatory standards for car bumpers, which specify that, at minimum, a car's safety systems must still function normally after a straight-on pendulum or moving-barrier impact of 4 km/h (2.5 mph):

Wikipedia article

  • Thank you for your response! This makes sense, but since it was dark (I added that piece of information), I thought I could have missed something. In general, is it realistically possible to negatively affect the safety of a car with such a minor accident? There was no person in the vehicle, so there's no direct effect, but I was wondering whether it's possible for a component like the bumper to "wear off" because of an accident like this. Commented May 31, 2018 at 5:14
  • @TodorPetrov I'd confidently say its impossible to negatively affect the safety or longevity of either vehicle that was involved in such a low speed incident.
    – WeakMech
    Commented May 31, 2018 at 5:43
  • Thanks again! So will that assume that what the other answer says is not applicable for such low-speed crashes? Commented May 31, 2018 at 5:48
  • In my opinion, a 2 mph accident at 2 metres is not going to deform the crumple zone of either car
    – WeakMech
    Commented May 31, 2018 at 6:12
  • And even at 5mph? Although I am not sure you can reach that speed in 2 metres, unless you press the gas pedal very hard. Commented May 31, 2018 at 6:24

Some cars can suffer serious damage - while the bumper and plate don’t show anything, crush or crumple zones can start to deform and reduce their effectivness in future accidents.

Have seen this on some cars - bumper is fine while the boot floor has a ripple in it.

Given you say there was nearly 2 metres of space why did you need to hit it?

This video may make the point ...: https://www.youtube.com/watch?v=aGOWtIuP204

  • There was no need. I am an inexperienced driver, so I just drove backwards and pressed the brake a little too late. Due to my lack of experience, I also didn't know how to handle the situation properly and that's why I left. A very immature decision indeed. How realistic is that to to happen, given that my car had no more than 2 metres to accelerate? And shouldn't this case still be visible? Commented May 31, 2018 at 5:24
  • so open the boot, lift up the carpet and look.
    – Solar Mike
    Commented May 31, 2018 at 5:27
  • I will do that. I was more concerned about the other car, since I cannot inspect it anymore. Commented May 31, 2018 at 5:30
  • I also, am only concerned about the other car....
    – Solar Mike
    Commented May 31, 2018 at 5:32
  • I will check the boot, thanks! But shouldn't that still be visible for both cars? Commented May 31, 2018 at 5:44

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