[Svip]

My understanding of speed limits in the US is that each state defines it. There is no national speed limits (hence why Montana is famous for its high speed limits on motorways, but not much else).

But I doubt that Washington D.C. uses kph on its speed signs, though.

[lancefisher]

In 1995 - 1999, our speed limit on the Interstate in Montana was "Reasonable and Prudent". The federal government set a national speed limit in 1974, and it was repealed in 1995. When that happened the speed limit reverted to what it was in '74.

I was in high school for a couple of those years. I drove 120 MPH frequently. I probably would have got pulled over for that. I had a friend who got pulled over for going 90 MPH. Ultimately, I think the ambiguity of "reasonable and prudent" led to the state enacting a 75 MPH speed limit.

http://en.wikipedia.org/wiki/Speed_limits_in_the_United_Stat...

[cglace]

Are you saying that Montana is not known for much else other than having high speed limits?

There are two incredibly beautiful national parks there, Glacier and Yellowstone. Yellowstone is one of the best known parks in America.

[YZF]

Yellowstone for the most part is in Wyoming.

[cglace]

You are right. It has been years since I have been there. However, for some reason I remember spending a good amount of time in the Montana portion. Don't know why.

[dgavey]

Arizona has some signs in Kilometers. [http://www.nytimes.com/2010/09/15/us/15highway.html?_r=0]

[chiph]

The last sign in the US that I saw marked in metric was one on northbound I-95 in South Carolina, just north of the I-26 interchange. The sign was replaced about 2 years ago with a new one that only shows distances in miles.

I suspect that metrication of the highway system in the US will only happen if a large state like California or Texas converts. But with the current budget situation, that's highly unlikely.

[xxpor]

The federal government has a law that federal funds can not be used to pay for signs with metric measures on them.

[benholmen]

Do you have a source for that?

[Torgo]

According to: http://www.fhwa.dot.gov/interstate/faq.htm

"the National Highway System Designation Act of 1995 prohibited the use of Federal-aid highway funds to convert existing signs or purchase new signs with metric units."

It appears from my reading of the law that the prohibition expired in 2000.

[xxpor]

Ha interesting. Didn't know abou that expiration.

[xxpor]

http://www.legistorm.com/score_gao/show/id/25766.html

"However, Congress passed legislation in 1994 and 1995 that prohibited federal funding for converting highway signs, such as those for speed limits, to metric units."

[derleth]

> Montana is famous for its high speed limits on motorways

This hasn't been true for years. Our current speed limits are in line with the rest of the country.

[maqr]

Ok, I'll bite, so what are you famous for now?

[derleth]

I doubt a resident can accurately answer this question.