I just got back from O’ahu, and on a section of H1 (one of Hawaii’s three Interstates) the speed limit is 35 MPH. I think this might be the lowest permanent speed limit on any Interstate (I certainly have never seen lower) - does anyone have another contender?
PS - the irony of an interstate highway in Hawai’i is not lost on me.
Nope. Lowest around here is a section of 35E through St.Paul with a 45 speed limit. It goes by a hospital complex and it was one of the compromises needed to get the damned thing built.
because it is the interstate and defense highway system and Hawaii needs national defense also.
Yeah, I don’t think we’re going to beat 35. There’s some places I can think where a spur route directly dumps out onto surface streets, in which case the last mile of the Interstate route might drop down progressively from 60 (or whatever) to 45 to 35, so technically there’s 100 feet or so of Interstate with 35 mph. I don’t think I’ve ever seen lower than 35, though, and that’s probably not really in the spirit of the question anyways!
I can also think of a couple of places where the entire flow of an Interstate route goes on ramps with low “suggested” limits. For example, you might read that I-90 is the longest stretch of limited access 4-lane highway in the world, but it isn’t so-- at the interchange with I-94 east of Billings, MT, you have to take a 1-lane ramp (with a 25 mph limit) to remain on I-90. Also probably not in the spirit of the question!
I know of a couple of Interstate passes that have 25 mph truck limits on the downgrades, but I don’t think I’ve ever seen a car speed limit lower than 55 for a pass.
Yeah, but what are the chances Hawaii would ever be attacked?
ETA: I assume tollbooth zones also don’t count?
I drove across the country once long ago and remember a stretch of interstate that basicaly runs right up to the edge of one of the Great Lakes, then does an absolute 90 degree right turn. Concrete walls on both sides.
I remember it so well because of the skidmarks, car parts and general carnage littering the area. It was surreal.
I think it was Cleveland. And I think it was posted 25 mph (but that would have been a yellow sign).
Could just be local jargon, but I’ve been told that our Main Street is also considered part of the (possibly old?) highway. That being the case, the speed limit hits a low of 20 MPH at one point near the town square.
Similarly, the same is said of the Main street in the town where I grew up.
It makes me wonder how common this is in rural America?
Where are you where an Interstate highway is routed via a town square? Are you sure it’s not a US or state route, or something like an Interstate business loop?
It is all about the military.
I do suppose it could be a US route. I just know a lot of people refer to it as a highway, and have been told (and seen) that it is a main thoroughfare for eighteen wheelers.
It’s more that the Interstate system gets federal funding. According to this post by Mr Downtown, the military really didn’t care a whole lot about freeways.
I-68 in western Maryland slows to 40 MPH as it twists its way over downtown Cumberland.
Can’t find the official posted speed limits for trucks going down Cabbage Hill on I-84 east of Pendleton, OR, but the ODOT pdf on the grade gives suggested limits for semis based on weight. For 75-80k the max is 18 MPH. And that’s in good weather. Throw in snow or ice and even that is suicidal.
It’s probably still fairly common for US routes, but not for Interstates, which were built later. It seems to have been fairly easy to route the new Interstate highways outside of town in rural areas. I have lived in two small towns that had US routes as their main street. One had an exit on the interstate, completed just before I was born, which was routed just outside town. The US route has been decommissioned in that area now, and the last time I was there, they had put the word “OLD” above the US 10 signs. The other town just recently had the US route rerouted to a new larger road outside town and the old road through town is now a county road with a different number.
More commonly, the old US route going right through town will become the business loop when the Interstate bypasses it.
I-70 in Breezewood, PA likely has a mighty slow speed limit for an interstate highway, being a massive stip of commercialism festooned with traffic lights.
If only they’d had Interstates back then!
Ssssoooo, do you know what that mighty slow number is?
There’s a section of I-40 in Winston Salem NC that used to have a speed limit of 45 where it went around a big twisty turn near a hospital. I haven’t been back there in 15 years or so, so I don’t know if it’s still like that.
This. The answer is stopped. Zero. Gridlock. Every hour of every day. Trust me on this. Driving through Breezewood is miserable and is best avoided.
