There is always the autobahn. If systems like that existed endangered there could be incredible time savings. A related question of mine is ‘If cars can go so fast why do we not find ways to raise speed limits while keeping roads safe?’
Why are assault weapons so difficult to own in Europe? They make them in the US and you can own them there.
As to your question - I’d like to refer you to physics. 2000 pounds of metal moving at any speed can kill pedestrians easily. More speed means more energy.
Increasing speed limits consumes more fuel, wears roads more, pollutes more tire and brake dust, and of course kills more. We should not make things more convenient for motorists just because motorists exist.
There are typically no pedestrians on highways. Being a pedestrian on a high way is hazardous no matter what the speed limit is for any realistic speed limit.
If the cars move faster, they will get off the road faster. This means fewer vehicles on the road and the distances between the vehicles will increase. It is a linear effect if you adapt a flow equation to vehicles. Here is the equation off the top of my head:
V1*D1*L1 = V2*D2*L2
V is the average speed, D is the linear density, L is the number of lanes. If you care about safety, you want D to be as big as possible so that vehicles do not have distances between them reach 0. That implies higher speeds (or more lanes, but that is harder to do).
Finally, the gun analogy is inappropriate. It is essentially saying “the data contradicts our conclusions, so let’s shutdown any rational thought that might question our conclusions”. This kind of thinking is backward and should easily lead to nonsense such as the rationalization of square wheels to give an example of the absurdity it allows. Interestingly, much of what you said could also be said in defense of the forced adoption of square wheels.
Traffic flow theory looks tidy on a whiteboard, but real roads don’t follow V D L arithmetic. Drivers open their following gaps faster than speed rises, so capacity peaks around 55 mph at roughly 2 000 veh/h/ln. Push limits higher and flow falls while crash energy soars. Because kinetic energy scales with the square of velocity (½ mv²), a 20 mph jump doesn’t give you 33 % more punch, it delivers nearly 80 % more. NHTSA data put it bluntly: fatal-injury odds about double for every 10 mph over 50 mph [1]. That’s an exponential climb in destructiveness, not a linear trade-off.
Higher limits also leak onto the streets that feed the ramps. The AAA Foundation’s 2024 before-and-after work showed a lasting uptick in operating speeds and speed-related crashes on arterials within a mile of interchanges after states boosted freeway limits [2]. Pedestrians and cyclists never set foot on the interstate yet bear some of the fallout.
Saying my analogy shuts down rational thought misreads what the analogy is doing. It's not a substitute for data but a framing device. I'm highlighting that different technologies share a core governance problem. When a private activity's danger rises faster than its utility, society uses regulation to keep expected harm below an acceptable threshold. This invites more rational analysis, not less.
If empirical data showed that 85mph highways or un-regulated assault rifles actually reduced third party harm, the analogy wouldn't block that conclusion, but instead lead to different regulatory settings. Your dismissal flips the burden of proof, hand-waving away the external-risk problem instead of engaging the numbers.
The gun analogy is serviceable once you zoom out from mechanics to externalities. An AR-15 and an 85 mph interstate both offer private utility but impose public risk that scales steeply—ballistic energy for one, kinetic energy for the other. Society uses licensing, background checks, or posted limits to push that expected harm below a tolerable threshold. Arguing that faster roads are safer because “cars clear out quicker” is like saying bump-stocks make rifles safer because the shooter finishes the magazine sooner: it flips the risk calculus on its head.
Think of operating a consumer-grade drone near people on the ground.
Private benefit: You get great aerial photos and save time compared with climbing a ladder or renting a lift.
External risk: If the drone falls from 100 ft it can hit a bystander with far more kinetic energy than if it falls from 20 ft (energy ∝ height, so the risk climbs steeply as you fly higher or faster or fly over people).
Regulatory levers: Aviation authorities cap altitude, require line-of-sight operation, limit flights over crowds, mandate geofencing near airports, and sometimes ask pilots to pass a basic safety test.
> Traffic flow theory looks tidy on a whiteboard, but real roads don’t follow V D L arithmetic.
I have been paying attention to speed changes while driving for the past 15 years and every time I have seen a speed change, I always observe a proportional change in the other variables, within the bounds of my ability to measure. For example, speeds drop when lane counts decrease, and the difference is in proportion to the reduction in lanes and change in vehicle density. The change in things in logically forced, since cars are not magically disappearing/appearing on the road.
Empirical studies have long supported the 85th percentile for vehicle safety. The spillover effect is a new thing that likely will affect the design of the ramps for highways, but does not justify violating the 85th percentile.
If we are going to consider other effects, how about the effect that happens when the roads no longer have the capacity to carry traffic from enforcing lowered speed limits? That will result in bumper to bumper traffic during rush hour, with enormous amounts of particulates and NOx released from having so many vehicles idling. These kill people both on and off the roads. This is a problem in NY where the low speed limits philosophy has been in effect for decades. The electric future cannot come fast enough. Of course, electrification does not solve the additional problem of people dying fairly quickly because ambulances cannot reach hospitals in a timely manner due to bumper to bumper traffic.
It is really easy to take the position that high speeds are the problem, but that ignores the problems associated with lower speeds. That said, I owe you a thank you for the information about the AAA study. I had been unaware of that. Thank you for the information.
I don't know what percentage of cars sold on the U.S. ever get transported across the Atlantic to the autobahn, but I'm willing to bet there are several zeroes between the decimal and the answer. I can't see how the existence of the autobahn an ocean away would actually be the answer for this question. Like, OK, fine, sell cars without limits on speed near the autobahn, but why the rest of the world?
I'm not even saying such cars shouldn't be available. I'm just asking why they're the default when so few people will ever actually care to drive over 100 mph.
