People who set Speed Limits deserve this Punishment

https://www.fhwa.dot.gov/publications/research/safety/97084/97084.pdf

It took you 16 hours to reply to me, and after only 2 hours you post "Cat got your tongue?"

I know you're a kid but it's still funny.

"Like 60mph on the highway."

You're lucky if your interstates are 60, the limits are 40-55 on most New York Interstates

I am obviously not going to reply when I am sleeping. I am not one of these internet addicts.

Go ahead and link the study that concludes raising speed limits will increase safety.

https://www.fhwa.dot.gov/publications/research/safety/97084/97084.pdf

I posted this in two other threads and created a whole thread on it.

And yet you give me only 2 hours to reply

Go to page 85.

85 on the PDF file, page 74 on the report

And notice how in the first paragraph it says non-random selection of interstates

What is also interesting is how they only raised it 10 mi/hour, in other words, not even really changing it. If they raised it to 100, or even unlimited and then see what would've happened. And looking at the summary tables near the end, interstate accidents did not increase by much, only 352 (<9%) in once case. If speed were the main factor they should have doubled. They should also re-do this study nowadays where modern cars are much safer.

"Based on speed data coli ected at four sites, it appears that the mean and
85th percentile speeds increase d 1 to 2 mi/h (1.6 to 3.2 km/h) after the speed limits
were raised to 65 mi/h (105 km/h). Based on the limited data collected in this study,
there does not appear to be an increase in the 99th percentile speed, which contains
the highest speed drivers."

Since driver speeds did not change, it could not have been speed that was the contributing factor to crash increases. It simply proves that drivers kept driving what they were comfortable at, regardless of the speed limit, which has been another one of my points all along.

"I also suggested you were obsessed though."

I admit, I do have a few videos I made on the subject, but it does not constitute an obsession or pathology. Judge for yourself.

(Just so you know, I'm not fully agreeing or disagreeing with you here, just saying what I saw)

Page 71 of the report gives the summary and notes that they did it both ways

1) Raised speed limits to within 5mph of 85th percentile

2) Lowered speed limits to more than 5 mph below the 85th percentile

And then they compared how crashes changed against a control group of roads where speed limits stayed the same.

Looking at their numbers myself crashes decreased when speed limits were raised, crashes decreased when speed limits were lowered, and crashes decreased on roads that were unchanged. They decreased in all cases, so we have to compare.

On page 73 Table 25 it gives the numbers, and it seems to me that lowering the speed limits resulted in 60 less crashes than the control roads while raising the speed limit resulted in 16 more crashes than the control roads.

Which is confusing because page 74 graph does suggest raising the speed limits to within 5mph of he 85th percentile lowered crashes while lowering the speed limit more than 5mph below the 85th percentile increased crashes. I don't know where they're getting those numbers from so I don't know what to say.

---

In any case, it seems the facts do support the argument that raising speed limits to match the speed of the 85th percentile is good.

This also seems sensible just like you'd want to put trash cans where you see litter and you want to build sidewalks where you see people cutting through the grass.

Page 133 of the report (144 of PDF) gives a summary.

Seems they raised it by:

"15 or 20"
10
and 5

They also lowered it by

"15 or 20"
10
and 5.

It says the speed limit was raised and lowered for experimental sites, ok, I understand that.

It also says the speed limit was raised and lowered at comparison sites... so I guess I don't understand the method, and I don't want to read it

But sure, like I said earlier, it seems there's data supporting crashes decrease when you raise the speed limit to match the 85th percentile.

Thank you for actually giving a reasonable mature reply unlike most other people my forums! I am curious where they got the 85th percentile from? Why not 90% or 70%? Applying that to what I see in New York, the speed limits should be 75 mph on most highways. 

Oops, it should say faster than 84% and slower than 16%. I made it quickly so it's not a perfect picture

I know what percentile means, I was asking how they determined that 85% was the best benchmark to split the difference.

No idea.

But again, it seems reasonable to me. If you posted no speed limit, then people's speed may be very different, so I think that would increase crashes

But letting people drive however they want would probably give you a good estimate for what the speed limit should be, because on average people probably pick a good speed.

I guess average is a little too slow though. It seems 85th percentile is good. Why 85? Maybe they wanted to test that because that's roughly 1 standard deviation on a bell curve. Other than that I don't know.