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Originally Posted by Dean
If there is enough time to get down to 20MPH, there is more than enough time to miss the object.
It's physics time again... braking distance is a square function, not linear...
Roughly speaking it is x² ÷ 20 + x = Overall stopping distance in feet. where X = speed
I think some of these distances are a bit long based on modern tires and brakes, but here goes anyway...
Using some Intarweb data we see that it only takes 40 feet to make an unplanned stop from 20 MPH. and only 20 feet of that is actually stopping. From 60MPH, it takes 240 feet, take away the last 20 feet for your 20 MPH stop, and you need 220 feet to get from 60 to 20.
Hope all the deer are kind enough to step out in front of you 2/3rds of a football field in front of you.
Most of the time braking should be done after making a directional change, but in todays ABS world, you can even steer after you brake. The problem is people don't! They stare at the object they are going to hit pedal jammed to the floor, and arms locked braced for impact.
Turn the F'ing wheeel! |
If braking distance vs. speed is a second order function, and Kinetic Energy is a second order function, then braking linearly reduces the energy in the system before impact. If you have twice as much distance available to you, you can reduce the energy in the system by half. Swerving only reduces the energy in the system by the tiny fraction of speed you bleed off due to tire scrub. You put all your eggs in the basket that hopes you don't hit anything, meanwhile increasing the chance that if you do hit something, it's not w/ the nicely designed front crumple zones, but with the side or the roof of the car.
Like I said earlier, I'd stomp on the ABS and steer away from the impact if possible. But I don't believe in attempting to swerve to avoid the impact. Maybe your definition of swerving is different than mine, but to me swerving is attempting to use 100% of your traction to change direction rapidly, which leaves no traction for braking. I say brake as hard as you can, if there's tire leftover, steer away. Don't swerve.