Driving at roughly the same speed as the rest of traffic is definitely much safer than driving the posted speed limit.

Any other such commonly observed violation would probably have to be studied to answer the question - and given humans' tendencies to take on a fairly uniform level of risk no matter what the rules are, I suspect the question may need to be "does this keep the risk level constants while increasing throughput" rather than "does this reduce risk".

So ... it's plausible both ways so far as I can tell.

> Driving at roughly the same speed as the rest of traffic is definitely much safer than driving the posted speed limit.

Who is causing the danger of driving the maximum legal speed.

Also, it's rare that all of the traffic flow is above the maximum legal speed. The ones speeding then cause the differential, which is the danger.

The fault is not with those not keeping up. But rather with those breaking the law because it's convenient.

Maybe it's rare where you are, but it's common for traffic to flow at greater than the speed limits in many places. Here in the DC area, for example, if freeway traffic isn't so dense that it's jammed up, it's probably flowing at 5-10 MPH over the limit. I usually drive at 60MPH in 55MPH zones and stick to the right lane because I'll be one of the slower cars on the road. Sometimes the difference is so great that 60MPH is still too slow to be safe and I bump it up a bit more.

What one ignores is the traffic that you pass when you're going 65 in a 55. I would estimate probably 1/4 of traffic is moving at or just below the limit. I'm in Houston and we deal with traffic quite a bit and I'm not addressing rush hour bumper to bumper here.

The fundamental question is who is at fault for the differential in speed (i.e. that which increases risk of injury/death with an accident)?

The answer is the person who breaks the law and the one who does so as a precaution to themselves (i.e. following the flow of traffic). An accident by this group disproportionately affects those obeying the law.

So I see three groups.

1. The speeder. 2. The law abiding citizen. 3. The person who is aware of their surroundings and adapts.

Ethically between 1 and 2, 2 has the upper hand. 3, when driving with 1 increases risk to 2. But if 3 joins 2 they increase risk to themselves and to the larger group 1.

> Driving at roughly the same speed as the rest of traffic is definitely much safer than driving the posted speed limit.

Absolutely. I went into some details here: https://news.ycombinator.com/item?id=15495904