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