I've studied a ton of stats as well. You're mixing high level studies with general trends and not looking at specific studies of this topic.

I went out specifically looking for this detail, yes there was a dip in the 70s. I'm sure if I cared more about this topic I could find more...
http://onlinepubs.trb.org/Onlinepubs...67/567-008.pdf

EDIT here's a very specific study on the topic that supports what I'm saying and takes into account the various road types. Link is being difficult after I read it, maybe it will come back
https://crashstats.nhtsa.dot.gov/Api...ication/808637

Again, I'm not disagreeing with you that the limit should be higher on roads designed for it, and remain high and get the value of that. I'm disagreeing that there clearly is an increased accident and death stat associated with that higher speed limit; at some point it's simple physics with survivability slamming into something at 55 vs 70 mph, that's a huge difference.

 

Believe me, I have read all of these studies. There are huge communities attached to the movement to raise speed limits that discuss this topic too that I've also been a part of. This is something my interest in goes back 20 years.



There was a dip in the 70s, but it was not a long term trend and the dip was gone as soon as traffic volume rebounded. The bulk of the data in that study is from rural roads. I'm only talking about interstate highways which were only a small part of that study. When you have reduced volume, you will certainly have reduced accidents. What that fails to prove is that reduced accidents were due to reduced speed limits and not reduced volume.

That link doesnt seem to work. But then how do you explain the fact that despite increasing speed limits over the past 25 years traffic fatalities have steadily declined? You would suspect the opposite would be true. You would also suspect that when they raise the speed limit on a highway they would find that they had increased accidents and fatalities and they would reduce the speed limit back down, that also almost never happens.

Clearly theres a survivability difference between hitting something at 50 vs hitting something at 70, but you have to look at what is the likelihood of there being an accident in the first place relative to the speed limit. The issue with limits set well below the 85th Percentile Speed is they create differentials in speed. You have cars driving legally at 55MPH on a roadway that has an 85PS of 70 MPH. That scenario increases the likelihood of there being an accident vs a roadway where everyone is driving at a more similar speed. That is how speed limits set below the 85PS actually make roadways less safe.

Its just way more complex than saying "raising speed limits increases fatalities" or "lowering speed limits decreases fatalities". The bottom line is, speed limits don't have a huge impact on the 85th Percentile Speed of a roadway. Drivers tend to drive what feels safe and natural for a road, and thats how roads are designed to be driven on. Raising the limits within that 85th range doesnt mean people drive faster. It just means driving the speeds they were already driving is now legal

 

I just don't see myself going under 75 unless I really have to on the freeway(s) that I'm native to. That's what everyone else does, and that seems like a pretty reasonable speed to me.

 

The 85th Percentile Speed, or the "flow of traffic"

 

If you go under 75, you'll have an enraged driver behind you tail gating. This is California.

 

I dunno...maybe traffic accidents vs traffic death against raising speeds is the real debate. I can’t imagine the death rate in a car accident decreases as the speed of the car increases

 

Of course it doesn’t, but that’s not the real question. Of course an accident at 80 is deadlier than one at 55 but that doesn’t mean 55 is the safest limit for the roadway.

 

It's an obvious and easy explanation that I already posted above a couple of times and don't understand why you think it would be the opposite at all? Continuous improvements in vehicle safety features and design have enabled that steady fatality decline (regardless of the speed limit).A 70 MPH crash is much more survivable in a modern vehicle vs one from 25 years ago, and as older vehicles cycle out of the pool of those on the road, driving gets safer as a whole every single year. These are simple improvements in the image below, and as a personal example I'm sure you know at least some of the advanced safety features on your previous LS460 compared to your dad's LS430 or his LS400.



Also a good summary here https://www.wired.com/2017/02/watch-...-20-years-ago/
and https://www.nhtsa.gov/newer-cars-are-safer-cars which has a pretty impressive comparative statistics of year-over-year improvements even though outside your date range "The average vehicle on the road in 2012 would have an estimated 56% lower fatality risk for its occupants than the average vehicle on the road in the late 1950s."

I feel very safe in saying a crash at 70mph vs a crash at 55 mph - in like conditions and in the same vehicle - is going to be statistically more deadly and damaging at the faster 70 mph speed. Unless you have some sort of Harry Potter wand to wave 'deathicus avoidus' you can share with me, there really is no way around the laws of physics.

 

I practically never speed. Usually just the speed limit. I am kinda too old to really care anymore TBH. If it is a long distance drive I might speed

 

Of course, I’m not denying any of that. Those are all reasons why higher speeds on roadways are safer today than they were in the past. Another reason why keeping speed limits below the 85PS on a highway doesn’t make roads safer. It generates municipalities more revenue.

 

LOL, but you did deny it as quoted above. I guess bad wording on your part, I wouldn't have posted all that otherwise.... Revenue has nothing to do with my posts or physics.

I totally agree higher speeds are safer than they were in the past because vehicle safety and drivability has improved. Higher speed crashes are still more deadly than lower speed crashes, period (like for like). The driver is also a significant factor; I'd much rather see an 80-year old grandmother going 55 vs 85 in her Buick , same for an inexperienced learner's permit driver. There's a wide range of drivers that can operate at the slower speed more safely - for them and those around them. Those drivers are also the ones that cause more issues at the 85PS limit road.

Again, I'm totally in favor of the faster speed limit personally and agree with driving closer to the road's designed speed, but I understand there are also good reasons for lower limits and don't deny they are valid.

 

I absolutely didn’t deny that, you misunderstood me. Obviously cars today are much safer, I said that multiple times, I also said multiple times that obviously higher speed crashes are more deadly.

The flaw in your logic about lesser drivers is, you don’t have to drive the speed limit. If you can’t or don’t want to drive that fast you don’t have to legally, just be sure to practice proper lane etiquette. The issue is ticketing people for driving their cars safely with the flow of traffic on roads with speed limits far below the 85PS or the flow of traffic. Most police make up for this issue by not ticketing people who are driving that way, but they can. And in many places they do, especially in small municipalities that rely on that revenue.

Another big issue is the total erosion of lane etiquette in the US. Seriously, people just do not practice this anymore. Riding along in the left lane, ignoring or not understanding drivers behind flashing to pass and forcing them to pass on the right. I have noticed a DRAMATIC change there over the last 20 years.

 

Lol So true haha

 

So true. In California, it's downright frustrating. I noticed however while driving across the U.S. that in many other states (specifically on two lane highways), people are more observant of the "keep-to-the-right-unless-you're passing" rule. I think the reason putting the speed limit at the 85th percentile makes sense is not to reduce lethality of crashes, but reduce the likelihood of a crash. Right now, at least in CA, if you're 65, I am going to pass you and from the drivers I see, most people would. By having the speed limit at, say, 70 or 75, I (hopefully) wouldn't have to worry about people going 65 in the right lane lol or getting pulled over by an officer. At the end of the day, if you're driving safely on a freeway going 75, you really shouldn't be getting pulled over and fined.

 

Sometimes there are valid reasons for staying (or getting into) the left lane, even if you aren't doing well above the speed limit. First, some of the freeway exit-ramps are to the left instead of to the right...and you must obviously be in the left lane to use them. Second (and this is often the case on the Beltway and I-66, particularly at rush hour), the solid line of traffic to the right of you, with everyone in a hurry, simply won't let you in if you do want to get out of the left lane and pull to the right. Third, emergency vehicles are sometimes trying to get by, and you want to give them room no matter what lane you are in. Fourth, the left lane you are in may simply disappear, due to construction-cones or the roadway's actual design, and what was the center or right lane becomes the new left-lane. Fifth, in the winter, you sometimes have trucks in the left lane, even when the road is still clean and dry, laying down the salt-brine stripes in anticipation of a winter storm....you can't expect them to do 75 or 80 MPH LOL. There are a number of other reasons as well, but that covers some of the more common ones.