Defensive Driving: Reduce Impact Force in Collision

  • Context: High School 
  • Thread starter Thread starter Ulnarian
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Discussion Overview

The discussion centers around strategies to reduce the force of impact during a collision while driving, particularly in urban traffic scenarios. Participants explore various approaches to minimize damage if a collision is unavoidable, considering factors such as speed, direction, and surrounding traffic conditions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that slowing down as much as possible can reduce the overall energy and momentum of the collision.
  • Others propose that ideally moving away from the merging car in the same direction could lessen the impact damage, though this raises concerns about potential collisions with other road users.
  • One participant emphasizes the importance of maintaining a safe stopping distance by increasing the gap between vehicles, particularly in traffic situations.
  • Another viewpoint highlights the necessity of emergency braking techniques, especially in vehicles with or without ABS, and the importance of practicing these techniques in safe environments.
  • A later reply questions the assumption that avoiding a collision is impossible, suggesting that if the merging car is moving faster, it may still be possible to avoid impact with mild braking.
  • There is a discussion about matching the velocity of the other car to reduce the force of impact, contingent on the surrounding traffic conditions.

Areas of Agreement / Disagreement

Participants express a range of strategies for reducing impact force, with no clear consensus on the best approach. Some agree on the importance of slowing down, while others debate the effectiveness of matching speeds or moving away from the merging vehicle.

Contextual Notes

Participants note various assumptions, such as the conditions of traffic, the presence of other vehicles, and the capabilities of their own cars (e.g., ABS). The discussion reflects differing opinions on the best practices for emergency situations without resolving these complexities.

Ulnarian
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Living in the city, it seems that some jerk tries to merge right into my car on a daily basis during rush hour (i.e. they try to come into my lane without even looking if I'm there or not).

Assuming that avoiding a collision isn't possible, what is the best way to reduce the amount of force of the impact? Do I slow my car down as much as possible? Do I speed up my car to match the velocity of the other car? Any ideas?

Thanks!
 
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Slow down as much as you can, reduce the overall energy and momentum of the collision.
 
A way to reduce impact would to be ideally move away from the merging car in the same direction so that less damage occurs.
 
joshmdmd said:
A way to reduce impact would to be ideally move away from the merging car in the same direction so that less damage occurs.

But then you risk collision with other road users or shortening your own stopping time if someone else does something.

The law (in the UK, which I happen to agree with) says that when you have someone cut in in front or behind you, you should increase the gap between you and the car in front to ensure you have a safe stopping distance. Not that you should accelerate, swerve etc out of the way.

Note, I can understand accelerating away if the road is clear (seems the obvious choice), but I assumed this was during traffic.
 
In traffic, trying to slow down as rapidly as possible is your best choice. Given short reaction time, if your car has ABS, just slam the brakes. Pretty much all you can do. If you have no ABS, then application of brakes is the matter of surface conditions. On fresh snow, slamming the brakes is the worst thing you can do with no ABS. But hopefully, you know how to perform proper emergency braking on your car. If not, it's a good idea to find an empty parking lot and practice.

Unfortunately, very often, not hitting the guy who cut you off means getting hit by the guy who's been tailgating you. On the plus side, the later is the fault of the person behind you, regardless of whether you can prove that the guy in front of you cut you off. In most places, if both collisions happen anyways, it's still the fault of the guy in the rearmost car. So emergency braking is your best bet both in terms of minimizing damage and in minimizing legal troubles.
 
Ulnarian said:
Assuming that avoiding a collision isn't possible, what is the best way to reduce the amount of force of the impact? Do I slow my car down as much as possible? Do I speed up my car to match the velocity of the other car?
It's not clear to me how avoiding impact isn't possible if the other car is moving faster than you. If it's moving faster than you and merging into your lane at the same time, it would have to have started the lane change almost behind you in order for mild braking on your part to not avoid the collision.

As far as reducing the force of impact from a collision, you want to match the other cars velocity, both the speed and direction, assuming this doesn't result in hitting other surrounding cars or objects.
 

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