Hacker News Reader

Comment by iainmerrick | Hacker News Reader

I was thinking the same. One earlier article about this had a rather inflammatory photo of some twisted-up cars next to an empty baby buggy. But if you watch the video, that’s clearly where some human drivers ploughed straight into the back of the pile-up.

The Tesla autopilot failure is really bad, for sure, but those human drivers should be banned for life. There’s no excuse for ramming into a traffic jam because you weren’t paying attention.

Edit: occurs to me that possibly I’m being overly harsh here. Is there something about the dynamics of traffic that puts the cars three or four slots back at greater risk when somebody unexpectedly stops? I would assume that the immediately following car is at the greatest risk, but after that everybody is at successively less risk as they should all be slowing and should all see each others’ brake lights.

View on HN

I believe there is a dynamic effect.

The first driver has some reaction time needed so he’ll start breaking after the Tesla starts breaking. Which means, assuming they were at the same speed initially, that the 1st car will have to break a bit harder than the Tesla.

Then the second car will be in the same situation, it will have to break a bit harder than then first. 5 cars later, you are at the hardest possible breaking power, as it’s ultimately limited by adherence.

So, if there’s not a larger gap in the thread of cars somewhere to allow for breaking less hard than the car in front, it’s more or less inevitable.

That's a nice explanation, I'll buy that!

To mitigate it, each driver needs to look 2 or 3 cars ahead, not just at the car in front. Everybody should do that but it's understandable if they don't (and it might be hard to see clearly, especially in a dark tunnel).

Good luck maintaining a safe distance on a busy highway when every time you slow to make a space, somebody moves into the space from a different lane.

Traffic jams happen. Do you really expect drivers to just ram into the back of them?

Traffic jams usually have some sort of sign, a slowing of traffic, a stream of brake lights ahead.

It's a different situation when someone is slamming on their brakes from highway speed with nothing ahead of them.

Exactly this. A traffic jam, by definition, is never running at highway speeds. If it was, it's not a Jam.

Why not let them take the space?

Because then you have to slow down to keep a safe following distance again. Then it happens again, and again, and again.

Why is this a problem?

One car driving significantly slower than the rest of traffic can itself be a safety problem:

"To keep a smooth traffic flow, some highways also have minimum speed limits. If you drive slower than the minimum speed you can halt the traffic flow and create a dangerous condition. Even if there is no minimum speed limit, those driving too slow can be as dangerous as those who drive too fast."

https://dmv.ny.gov/about-dmv/chapter-8-defensive-driving#yre...

You don't need to drive significantly slower than others, just slightly slower so a new gap appears in front of you.

The conversation you are in:

1. It's the fault of the driver behind, for not leaving space

2. It's impossible to leave space, because cars will move in if there is a large gap

3. Why is this a problem?

It is not impossible to leave space. Granted, you need to do it every time a car moves in front of you. But such is life.

Reply on news.ycombinator.com