Has anyone else noticed this?

[Dave1215]

Somewhere I read that if you took away all the speed signs and then monitored behavior that you would determine the best safe speed by taking the speed that the folks in the 85th percentile are doing and using that as the new set limit... the idea being that most reasonable folks have a feel for what is safe and not safe - those reasonable people (thus the 85th percentile idea) set the flow of traffic and that's the speed you want to set your signs at. Those folks know when its painfully slow (we've all seen those 30mph when 45mph made more sense) and those same folks know when it is uncomfortably fast...

Spoke to a cop one day and he said the 85th percentile idea is starting to be used more and more in places where they can record the speed of all cars over an extended period of time (like 5-7 days)..

[Katarina Witt]

On one trip out there to Nebraska we noticed that the speed goes up as one gets closer to Omaha. This was on I-80, coming from Colorado.

[Dave1215]

Originally Posted by Katiana

On one trip out there to Nebraska we noticed that the speed goes up as one gets closer to Omaha. This was on I-80, coming from Colorado.

Actually I-80 in the entire state is 75mph, unless you are in the vicinity of a metro area where it will fluctuate between 55 & 75...

[tpabes]

I think she meant that the speed of traffic increases, not the actual speed limit itself. I would tend to agree with her, although you always get the people who absoluetly fly through western Nebraska.

[Dave1215]

Originally Posted by tpabes

I think she meant that the speed of traffic increases, not the actual speed limit itself. I would tend to agree with her, although you always get the people who absoluetly fly through western Nebraska.

I'll agree with that...

[Dave1215]

Originally Posted by Dave1215

Somewhere I read that if you took away all the speed signs and then monitored behavior that you would determine the best safe speed by taking the speed that the folks in the 85th percentile are doing and using that as the new set limit... the idea being that most reasonable folks have a feel for what is safe and not safe - those reasonable people (thus the 85th percentile idea) set the flow of traffic and that's the speed you want to set your signs at. Those folks know when its painfully slow (we've all seen those 30mph when 45mph made more sense) and those same folks know when it is uncomfortably fast...

Spoke to a cop one day and he said the 85th percentile idea is starting to be used more and more in places where they can record the speed of all cars over an extended period of time (like 5-7 days)..

Found a Q&A on the 85th percentile concept: 85th Percentile Speed (http://www.dma.org/~ganotedp/85th.htm - broken link)

The trick is getting the good statistical measure, which up to now was never feasible to do (since you needed someone with a radar gun to record) and you couldn't do that at all hours of the day/night over an extended period.... but, now they have those speed detectors that actually record every reading and store the data so the cops can get a report for the entire week...

[Katarina Witt]

Originally Posted by Dave1215

Actually I-80 in the entire state is 75mph, unless you are in the vicinity of a metro area where it will fluctuate between 55 & 75...

Originally Posted by tpabes

I think she meant that the speed of traffic increases, not the actual speed limit itself. I would tend to agree with her, although you always get the people who absoluetly fly through western Nebraska.

Yes, that is what I meant, and it was my DH, the Nebraskan, who made note of this.

[Basalt]

As to the 85 percentile thing, I remember driving through Montana a few times when the Daytime speed Limit was wide open on the highway.

On the flats you had to cruise a steady 95 to 100 mph to avoid geting jammed by traffic, and even then most were passing, including 18 wheelers. The one time I tried to keep up in one stretch the speedometer was showing 115 to 120. and that was going into a bit of a winding section of highway along the Snake river.

Not sure that the 85 percentile rule would work so well on open highway, and residential areas. Speed Limits still temper those findings, and I believe once the limit was adjusted, traffic would still push pass the new limit.

On the whole I find myself doing about 5 over on the average just to flow with traffic, especially on two lane roads.

[keltec]

Funny, I drive Montana all the time and never find people driving like that, even on the interstates. There are actually several stated limits on sections of 25. I drive a high performance Mustang and don't drive like that either. Safe is safe and over 85 isn't safe. Most people's tires aren't even rated to go over 90 without risking a blowout. If your gonna drive that fast, you better be spending some serious money and buy Z rated tires as they will deal with the speeds like that. Others won't.

[ehenningsen]

Originally Posted by Katiana

Yes, that is what I meant, and it was my DH, the Nebraskan, who made note of this.

Funny that you say that Katiana, cause I noticed that too when I travel along I-80 to go to North platte or that area.. I need to do more research on that phenomena and if I find something I'll post my findings with the rest of y'all!