> You're ignoring a reality where a culture has _figured out on their own_ an optimal way to navigate from point A to B in bad traffic, (mostly) safely while constraining themselves to the _intent_ of the law, if not the letter.

Is it a reality? Sounds like conjecture to me, and the fact that many humans are killed in traffic fatalities certainly suggests otherwise.

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

France, specifically, has one of the highest rates of traffic fatalities in Europe. Roughly 3500 people die every year on their roads. If those cultural norms resulted in safer traffic, I'd be all for giving them precedence - they don't, though. So now you have to weigh the value of cultural norms around driving style vs. people's lives.

First 3500 is the total amount. You need the number of deaths that were caused by local trafic rules and could have been prevented by strict adherence to traffic laws. You'll be lucky if 5% of those meet that criteria.

You also have to weigh the lives against the value of the time saved -- the whole reason those norms exist. There's no way it comes out in favor of the deaths.

Let's try and ballpark whether it's worth it to speed 5km.

Roughly 410 billion miles driven yearly by the French.

The average speed of a journey in France is ballpark 60km/hr

Average salary is 36k in France with a 1450 work hours a year for €25/hr.

Putting it all together we get €0.42/km or €170B.

Now suppose that everyone always drives 5km over the limit bringing that average to roughly 65km/hr or €.38/km or €156B for a ballpark €14B in savings.

Say you can save 10% of those deaths by driving the speed limit which is extremely generous. I would take odds that not even 1% of the deaths could be traced to speeding 5km over but let's pretend. Even then each life saved still costs €400M.

Is it worth it?

If that were what caused it, maybe - do Germans drive slower than the French?

> You're ignoring a reality where a culture has _figured out on their own_ an optimal way to navigate from point A to B in bad traffic, (mostly) safely while constraining themselves to the _intent_ of the law, if not the letter.

But the intent is not always sufficiently appreciated.

Case in point, urban speed limits at 50Km/h in EU or 35MPH in US. For most drivers (me included), they feel terribly slow and overly precautious. Yet the intent has to do with stopping distance. In those areas, you should be prepared to come to a full stop on a very short notice because a child/dog/ball could be darting out in front of you with zero notice. Not only that but the cars behind you should also be able to stop. Whenever you're driving at 45 in a 35 zone, keep that in mind: not only you need to be ready to slam on your breaks but you must have enough distance with the vehicle in front of you, should they need to slam on their brakes.

Most people only consider the "happy path" scenario, not the "error handling" one.

I suppose, but lawmakers optimize for the 1% error case, actual drivers optimize for the 99% case.

Let me take a thougher position. The value society gains by upping the speed limit on a major road will quickly outpace the value of the lives lost due to accidents. It's just that the injuries and deaths are more visible.

The evidence should be that almost everyone drives at the faster speed anyway and 35mph roads aren't death traps.

Cultural norms have nothing to do with optimal driving. It used to be a cultural norm in parts of the US to drive around with a 6-pack of beer in the console, and one in your lap. Just because a culture has "unspoken driving rules" doesn't mean they're safe or sound.

> You're ignoring a reality where a culture has _figured out on their own_ an optimal way to navigate from point A to B in bad traffic, (mostly) safely while constraining themselves to the _intent_ of the law, if not the letter.

This is self evidently not true though. Humans are terrible drivers, and the road would be safer if all of those people who are unsafely not following the rules instead followed them.

The reality of the world that we live in is one of terrible drivers that get into lots of accidents.

> culture has _figured out on their own_ an optimal way to navigate from point A to B in bad traffic, (mostly) safely while constraining themselves to the _intent_ of the law, if not the letter.

Exactly. This is why the speed limit on highways is always min("one or two under the misdemeanor speed in this state" "as fast as conditions allow").

> as fast as conditions allow

This is the part humans (who almost invariably overrate their abilities at everything, especially driving) are really bad at determining.

> Who is the self-serving person who thinks they are entitled to travel to Paris and drive around without understanding the cultural norms of their unspoken driving rules?

Anyone licensed to drive in France, actually. The requirement is that they understand the traffic laws and regulations.