Rules of Defensive Driving

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Basically what I'm getting at is that in the real world, your load is a huge factor in what you decide to do in a given situation. It should be properly secured to where it's not going to shift... but real world. It doesn't matter how good your brakes are, the driver might just decide that scratching his bumper and giving you back problems or whatever isn't going to look as bad on his record. This is even more the case for liquid bulk. Food grade can't have baffles. You have thirty, forty, fifty feet of unimpeded mass sloshing around...

So yeah. Defensive driving.

Quintin_Stone wrote:

A braking vehicle only becomes a "simple" physics equation if all the tires are locked. That's the only time it becomes a simple formula of velocity, pressure, and coefficient of friction. Until the tires lock, it's an interplay of friction forces involving the road, the tires, the brake pad, and the disk or drum.

Jonman wrote:
Baredil wrote:
Jonman wrote:

the area of rubber that is contacting the road. The more rubber, the more force you apply under braking before a skid occurs (which braking force drops off precipitously).

Nope - friction is (mostly) independent of surface area.

http://www.mouatonline.com/Teachers/BHutchinson/Physics/Phys11/Unit%203/Surface%20Area%20&%20Friction.htm

I don't buy it.

If I drag a 1 square inch piece of rubber across a surface, I only need to apply a tiny amount of force.

What you're saying is that I can move a 1 square *mile* piece of rubber across the same surface for the same amount of force.

Which is clearly bullsh*t.

The force needed to overcome static or kinetic friction is the coefficient of friction (either static or kinetic) times the force perpendicular to the surfaces. In your example, a square mile of rubber would have a force 4,014,489,600 times that of the square inch because of the weight of all that rubber.

What is this ? MATH!? Burn the heretic!

I'm still catching up (starting page 7), but I honestly started this thread thinking it was a metaphor. Maybe it still is.

LarryC wrote:

I've been mulling over something on a policy level. This is not defensive driving and goes against the spirit of the thread, but since we went there already anyway...

I am a motorist more than I am a cyclist. I am a recreational cyclist, but a commuting motorist. I would like to commute more by bike, but the distance is too far (over 50km one way).

The overarching transportation principle I was thinking of is this: regardless of any other traffic rule, in a dispute, the smaller party always has right-of-way. This means that trucks are legally mandated to yield to cars, cars to motorcycles, motorcycles to bicycles, bicycles to unicycles, and all to pedestrians.

Different rules would apply to freeways and highways, of course; and on the design level, these thoroughfares could be made unattractive to smaller vehicles through tough inclines and monitored gateways.

There's this thinking that having smaller vehicles have right-of-way would lead to chaos and possibly over-aggressive pedestrians, but as with aggressive drivers, that problem is even more self-limiting. If you run over a pedestrian by accident, you might get comvicted of a misdemeanor, but that person is dead or permanently disabled and will never bother the roadways ever again.

For what it's worth, this was the original policy in the US. It was well and thoroughly lobbied away.

Some discussion here:

I'm skimming somewhat, and this has probably been posted, but I wanted to share these

My father taught me, if you are waiting at a junction and a car approaching is indicating to turn into the road you are on, never pull out in front of them because they could either not realise their indicator is on or they might change their mind at the last second. Also, don't swerve to avoid an animal in the road you could hit a car coming the other way.

Higgledy wrote:

I'm skimming somewhat, and this has probably been posted, but I wanted to share these

My father taught me, if you are waiting at a junction and a car approaching is indicating to turn into the road you are on, never pull out in front of them because they could either not realise their indicator is on or they might change their mind at the last second. Also, don't swerve to avoid an animal in the road you could hit a car coming the other way.

Sound advice. I base my decisions more or less on car physics. It's not turning right until the bulk of its mass says so; indicator light notwithstanding.

Haven't bothered to read the original, but this response article on Jalopnik has a good rule for defensive driving:

One, we shouldn't always, at every moment, have to be thinking about 'productivity.' Sometimes getting to work is enough. And B, when you're driving to work, just f*cking drive.

[...]

Or, if it's just not for you, try and hang tight. We're really close to robots driving your ass to work, anyway, and then you can email and tweet and be so freaking productive all the time you'll explode in a big, wet ball of achievement. Congratulations, winner.

Bolding mine.

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