[Zak]

People driving at the speed of surrounding traffic are not creating a particularly high risk even if their speed exceeds the posted speed limit. People driving at a different speed from surrounding traffic do create an unusual risk, even if that speed is legal and the other drivers are speeding.

This becomes less true in places like Germany where lane discipline is very strict. It's not rare to see extreme speed differentials on unlimited speed sections of German Autobahns, but it is rare to see crashes there.

[KennyBlanken]

> People driving at the speed of surrounding traffic are not creating a particularly high risk even if their speed exceeds the posted speed limit.

The whole "everything is fine as long as everyone is doing the same speed" bit is a myth.

For every percent increase in speed, this leads to a 2% change in injury accidents, a 3% change in severe injury accidents and a 4% change in fatal accidents.

https://road-safety.transport.ec.europa.eu/eu-road-safety-po...

More about speed vs injury/death rates:

https://www.iihs.org/news/detail/new-crash-tests-show-modest...

https://safety.fhwa.dot.gov/speedmgt/ref_mats/fhwasa1304/Res...

Why? Kinetic energy is a function of velocity squared, influencing injury severity and stopping distances.

[ryandrake]

Just to be clear, are you and others in this thread advocating driving the posted 45MPH speed limit on a highway where the actual flow of traffic is going 65MPH? And you don't think that's going to be disruptive to the point of causing accidents?

[superkuh]

Just to be clear, are you and others in this thread advocating for driving 20 mph faster than the 45 mph speed limit just because you see other criminals doing the same? That's wildly illegal and would probably get your license revoked.

[Zak]

That's essentially the situation on the highways through Atlanta. It's so extreme that some students made a video[0] demonstrating the extreme effect on traffic when drivers in every lane maintain the speed limit.

Their conclusion is that the speed limit should be increased; there are other reasonable conclusions one might draw, but I would argue against the one that follows from your comment: that nearly every driver on the road deserves punishment.

[0] https://www.youtube.com/watch?v=OoETMCosULQ

[superkuh]

Changing the speed limit to the current status quo "speeding" is the reasonable thing, yes. We've already accepted that rate of lives lost at the higher speeds so make it official. Law breaking while driving should not ever be the status quo. It's an absurd situation that one almost has to break the law to drive.

I would be very interested in if people would then go the reasonable new speed limit or if they would continue in their speeding flocks and only travel even faster. To me it seems like their speed is mostly something they evaluate relative to the rest of the drivers and not to absolute speeds so it'd take quite a change in behavior.

As for [0], the traffic back-up proves only that the vast majority of people on that road are speeding.

[Zak]

Maybe there's better research available, but this DOT report found that changing speed limits has fairly little effect on how fast people drive: http://www.ibiblio.org/rdu/sl-irrel.html

My take on it is that when the speed limit doesn't match the 85th percentile speed of actual drivers, something should be changed. Sometimes, (often, in my view) it's the speed limit. Sometimes, it's the design of the road, especially in cases of neighborhood streets that are shaped like highways. Sometimes the answer may be highly-visible traffic cameras, as the advance warning and certainty of punishment will slow down almost every driver.

[JoeAltmaier]

Illustrating the difference between being a safe responsible driver, and pedantry.

[JumpCrisscross]

> People driving at a different speed from surrounding traffic do create an unusual risk, even if that speed is legal and the other drivers are speeding

Driving the limit in the right lane is almost always fine.

[superkuh]

People who do not drive the speed limit are objectively breaking the law. And generally each flock travels at a different speed. After all, they have no way to communicate a common speed standard like, say, a speed limit.