Hacker News Reader

I've heard Defensive Driving described as driving with the assumption that someone else is going to do something wrong, and to be in a position to defend yourself from that eventuality.

The opposite is to drive Offensively (ha ha) which I guess is to assume that every other car will do the right thing and it's okay if I take a few risks.

I wouldn't say that at all since you're not assuming people are going to do something wrong per-se, you're more willing to accept that a situation that looks normal is going to turn out differently and be aware of how you can avoid any driver who's going to do that stupid thing.

I drive with the assumption that everyone else is drunk. Most friday night around here, it is true.

In the morning, I drive with the assumption that everyone is half blind and too aged to drive. I work next to an eye clinic, so this is also true.

Drive like everyone else is a fool and you should make it back home safe.

...look at every car that I can see, using every gap, window, mirror etc to be aware of my surroundings. Look at people, bus stops, crossings, shops in towns etc.

In my experience a shortcut to this level of awareness is to regularly cycle in commuting traffic. Not only does one notice much more, but one also notices the classes of things that it's actually impossible to notice from an autocage. (Examples: what most drivers are doing in addition to driving, where pedestrians are hiding, how a line of traffic moves through signals in fits and starts, etc.)

I cycled 150 miles for charity once, you soon pick up on extra things - having been knocked before.

That's a kind of brute force approach. It seems sub optimal but I don't know how to reason about it.

Should I say that observing every vehicle across the median on the oncoming carriageway is inefficient? Well I can't say that because occasionally some small cargo or even a wheel falls off and bounds across to the oncoming lane - something you definitely want to see coming.

Perhaps taking a zonal approach is as effective and certainly less taxing on the driver.

Scan each zone, some zones get scanned more frequently, and look for anything unusual.

Defensive driving is really just a specific application of situational awareness [0]. With practice and experience you'll go from just maintaining visibility and space for reaction time to actually remembering where drivers are that have been blocked from your view by other vehicles. You never really track every vehicle and pedestrian, but you do make note of particular ones and the rest get lumped into groups based on their behavior. You'll learn to anticipate the car that's going to make a left turn in front of you by taking your foot off the throttle earlier instead of braking at the last second.

[0] http://en.wikipedia.org/wiki/Situation_awareness

you're talking about chunking: at first you try to remember everything, then as you gain experience you learn you can abstract certain items away to a general model of them (chunk) without having to remember the specifics of each individual item.

Like everything related to driving, it eventually becomes automatic.

It's not that you're consciously looking at each car and saying "Is this car going to be a problem? Is this one a problem?" Instead, you recognize patterns. If a car suddenly weaves out of its lane, it triggers a tinge of fear and you give that car a wide berth until you can pass him and leave him behind. If you see brake lights go on 10 cars ahead of you, you know that you're going to have to slow down, so get ready for it (oftentimes, I'll let up on the gas as soon as I see brake lights go on a quarter mile down the road, and by the time I get to the traffic, I'll be going their speed anyway). If you're in a car's blind spot, pay extra careful attention to turn signals or any deviation from his lane, and try to pull forward or behind so he can see you. If a car is clearly in a rush, it's a good bet he's going to weave in front of you, so hang back and make sure you have room to adjust if he does. If two cars try to enter the same spot in the same line (this is my personal biggest fear, they're both in each other's blind spot and each has reason to believe the lane they're switching into is clear), hang back, and honk if it's clear that they don't see each other.

It's about pattern recognition, knowing which situations are dangerous so you can be extra careful whenever it looks like one of those situations is happening.

"That's a kind of brute force approach. It seems sub optimal but I don't know how to reason about it."

Well, what else are you doing while driving?

For the most part, whatever your answer is to that question, stop it. (Reasonable exceptions apply; conversation with another in the car isn't too big a deal, of course.)

Now that you're just driving and not doing anything else, you might as well be active about it and be on the lookout for long-tail risks, since really long-tail risks are all you ever have to worry about. Driving is fairly safe and almost everything that ever happens bad is long-tail in the first place or we wouldn't drive.

Agree 100% with "if you are doing something else while driving, stop it". I have always thought the conversation is the distracting part, not the act of holding a phone to your head. Research shows that it's less distracting to talk to a passenger than a phone conversation: http://scienceblogs.com/cognitivedaily/2007/01/24/want-to-dr... (link in article). Still, I prefer to remain focused on the driving conditions.

I'm not sure I agree that "driving is fairly safe" though. We have mitigated much of the risk associated with driving with vehicle impact standards and road design. I still really feel that most drivers don't understand the magnitude of what they are doing - they become accustomed to the relative safety and start doing other things. It seems the more safety we "build into the system" the more risks people are willing to take. I'm not suggesting we take safety out of the system though!

A zone won't hit your car...another car will.

Some things need to be brute forced.

I learnt these techniques from the IAM [0] in the UK. Their manual is Roadcraft - the Police Driver's Handbook [1] which introduces techniques which I've found incredibly valuable.

[0]: http://www.iam.org.uk/ [1]: http://www.amazon.com/Roadcraft-Police-Drivers-Handbook-Foun...

That's how you drive in third world countries.

It's the right way to drive anywhere hundreds of barely-trained primates are distractedly operating heavy equipment at high speed...

I use that technique, and during a period in which I commuted, my meditations on cars taught me to use the same principles of thorough research and prediction to analyze stocks, which worked out well. It can also apply to understanding a room of people or a crowd. Those are all situations where overconfidence can be worse than overcaution.

I think defensive driving is a good way to introduce that kind of prudence to people who would otherwise not pay close attention to things because piloting an auto is frightening at first so makes a person receptive to whatever makes them safer and gives them confidence.

Even beyond that, there's an overall 'field' of cars for me. Peripheral vision gets an overall sense of all cars in the proverbial neighborhood, and looks for scary patterns. Little things that seem harmless (and maybe are) put me on edge and make me guard my brake.

My wife didn't understand at first, but after 12 years of driving with zero accidents, it becomes apparent that it works.