Least Common Speed Limit

[interstatefan990]

What is the least commonly posted speed limit in the US? This excludes anything below 20 MPH or above 80 MPH, and temporary work zones.

My guess would be 60, I don't know if it's just me but the only times I've ever seen that anywhere in the Northeast was approaching a couple of population centers along I-95/Maine Turnpike. Maybe it's more common elsewhere?

[Big John]

60 in Wisconsin,  more limits at 55, 65 and 70.

[1995hoo]

Virginia has a fair number of 60-mph zones, but on the whole they are less common than most of the other numbers. I'd guess 60 is probably correct in terms of "normal" speed limits.

The least common one I've seen was 27 mph on James Street in Durham, North Carolina, in the mid-1990s when I was attending Duke. The speed limit signs were standard signs in all ways other than the bizarre 27-mph limit. I don't recall what the reason for posting it was, but I know it's no longer there–it's been changed to 25. But, of course, 27 mph is nonstandard and weird, hence my use of the phrase "'normal' speed limits" in the previous paragraph.

[interstatefan990]

Virginia has a fair number of 60-mph zones, but on the whole they are less common than most of the other numbers. I'd guess 60 is probably correct in terms of "normal" speed limits.

The least common one I've seen was 27 mph on James Street in Durham, North Carolina, in the mid-1990s when I was attending Duke. The speed limit signs were standard signs in all ways other than the bizarre 27-mph limit. I don't recall what the reason for posting it was, but I know it's no longer there–it's been changed to 25. But, of course, 27 mph is nonstandard and weird, hence my use of the phrase "'normal' speed limits" in the previous paragraph.

And not to mention an obvious violation of the MUTCD's 5-MPH-increment rule.

[oscar]

What is the least commonly posted speed limit in the US? This excludes anything below 20 MPH or above 80 MPH, and temporary work zones.

Which excludes the most uncommon (regrettably) speed limit in the U.S. -- 85mph on part of TX 130.

[jeffandnicole]

Absolutely no way to quantify this, but of normal speed limits, these seem to be the more lightly used ones:

60 mph
30 mph
40 mph

25, 35, 45, 50 & 55 tend to be used quite regularly, and 65 and above used when allowed.

[Flint1979]

I think in Michigan 60 would be it.

[interstatefan990]

What is the least commonly posted speed limit in the US? This excludes anything below 20 MPH or above 80 MPH, and temporary work zones.

Which excludes the most uncommon (regrettably) speed limit in the U.S. -- 85mph on part of TX 130.

That's exactly what I had in mind when I excluded limits over 80. I knew that would be the first thing a lot of people would think of, being that it's the record-holder. But it is still an outlier.

[interstatefan990]

Absolutely no way to quantify this, but of normal speed limits, these seem to be the more lightly used ones:

60 mph
30 mph
40 mph

25, 35, 45, 50 & 55 tend to be used quite regularly, and 65 and above used when allowed.

My inner New Yorker screamed when I saw 30 MPH on that list. NY is obsessed with posting 30.

[1995hoo]

Absolutely no way to quantify this, but of normal speed limits, these seem to be the more lightly used ones:

60 mph
30 mph
40 mph

25, 35, 45, 50 & 55 tend to be used quite regularly, and 65 and above used when allowed.

Regarding 40 mph, I remember hearing something once from a traffic safety worker, I think from VDOT, that there have been studies showing that more people suffer from depth perception issues at 40 mph than at 35 or 45 and that there was some desire to reduce the number of 40-mph zones because of that. But I don't recall him saying whether the studies were able to determine the reason for that. It sounded strange and bizarre to me. Off the top of my head I can immediately think of one 40-mph zone not far from here (Rolling Road in Fairfax County between Braddock and Old Keene Mill Roads), but 45 is more common.

[JayhawkCO]

What is the least commonly posted speed limit in the US? This excludes anything below 20 MPH or above 80 MPH, and temporary work zones.

My guess would be 60, I don’t know if it’s just me but the only times I’ve ever seen that anywhere in the Northeast was approaching a couple of population centers along I-95/Maine Turnpike. Maybe it’s more common elsewhere?

I-25 has a 60 mph zone on the south side of downtown, but off the top of my head, that's the only one in Colorado.  There are no 70 mph zones that I'm aware of.  I also can't picture a 50 mph, but I'm less confident in my take there.

Chris

[ilpt4u]

Indiana likes 60 - since it is the non-freeway (rural) Divided Highway default limit

I feel like 50 is used fairly sparingly - but maybe I just miss the 50 MPH Zones

[Scott5114]

60 is used a lot in Oklahoma as well, as the default urban freeway speed limit. 40 is used a lot here for 4-lane urban arterials.

50 is one that you don't see a lot around here–I can only think of one 50 MPH zone, and that's SH-9 (divided expressway with traffic lights).

[Pink Jazz]

The only 60 mph highway in Arizona that I know of is SR 238, and it was only introduced as recently as 2018 (raised from 55 mph).

There are no 70 mph highways in Arizona that I know of (Arizona law doesn't allow speed limits higher than 65 mph on non-Interstates, and I don't know of any segments of Interstates in Arizona posted at 70 mph).

[formulanone]

Based on the original post's restrictions, it's probably 75 and 20.

Comparatively few places regularly post anything lower than 25, and not than many states can post 75mph signs.

[Revive 755]

There are a decent number of places that use 60, though it is on the rare side in Illinois and Iowa:

Missouri:
* Urban freeways around St. Louis and Springfield, plus I-70 through Columbia.
* Multiple rural two lane roads
* Certain expressways (US 65 around Branson, MO 30, US 61 north of I-70)

Illinois
* I-294 from the north end at I-94 to north of O'Hare, plus another spot between I-55 and I-57
* I-290 from around IL 72 to around IL 390
* I-90 east of Elmhurst Road to somewhere around I-294
* I-74 through Champaign - Urbana

Iowa
* Parts of I-380 through Cedar Rapids?
* Parts of I-235
* I recall a 60 mph section on eastbound I-80 approaching the western I-35/I-235 interchange

Nebraska
* I-129?
* Part of I-180
* Part of I-480
* Used to be a lot more before the last round of increases that bumped many two lane roads in the eastern half up to 65.


As to 75, it's fairly common after the first row of states west of the Mississippi.

[US 89]

I don't know of any 60 mph zones in Georgia off the top of my head. Other than the 70 mph interstate maximum, it's relatively rare to see an x0 speed limit in the greater Atlanta area.

Utah's least common is probably a tie between 60 and 75 now. 75 is only found on a few segments of rural interstate that are either too mountainous or too exurban to get a bump to 80. Likewise, 60 is mostly limited to a handful of urban expressways or rural 2-lane roads that didn't quite make the cut for 65. Interestingly, unlike Atlanta, both x0 and x5 limits are pretty common in the Salt Lake metro with maybe a slight preference for x0.

[EpicRoadways]

I guess going off of the 20-80 rule Minnesota's would be a tie between 75 and 80 with exactly zero examples of both  . Otherwise, 20 and 25 are pretty uncommon outside of Minneapolis and Saint Paul because 30 is the state-designated unsigned speed limit on urban streets and roads are rarely signed below that (again, exempting Minneapolis, Saint Paul, and a few other communities). On the other end of the spectrum, 30, 40, and 60 seem to be the most common.

[jeffandnicole]

Absolutely no way to quantify this, but of normal speed limits, these seem to be the more lightly used ones:

60 mph
30 mph
40 mph

25, 35, 45, 50 & 55 tend to be used quite regularly, and 65 and above used when allowed.

My inner New Yorker screamed when I saw 30 MPH on that list. NY is obsessed with posting 30.

Absolutely no way to quantify this, but of normal speed limits, these seem to be the more lightly used ones:

60 mph
30 mph
40 mph

25, 35, 45, 50 & 55 tend to be used quite regularly, and 65 and above used when allowed.

Regarding 40 mph, I remember hearing something once from a traffic safety worker, I think from VDOT, that there have been studies showing that more people suffer from depth perception issues at 40 mph than at 35 or 45 and that there was some desire to reduce the number of 40-mph zones because of that. But I don't recall him saying whether the studies were able to determine the reason for that. It sounded strange and bizarre to me. Off the top of my head I can immediately think of one 40-mph zone not far from here (Rolling Road in Fairfax County between Braddock and Old Keene Mill Roads), but 45 is more common.

For both of these, my experience mostly originates here in Jersey, along with what I have seen in Pennsylvania and Delaware. The limits I mentioned are certainly posted...just less frequently than others. Growing up, when I left my development, the first street we encountered had a 40 mph limit. But overall these limits, at least from what I'm used to, are the ones I generally see the least.

As far as 60 goes, I've seen it twice in NJ: The first time was on a single NJ Turnpike older flip--style changeable speed limit sign.  The Turnpike wouldn't have intentionally used that limit, so it was probably a malfunction which those signs were prone to. The only other time was on the AC Expressway, where a median project had a 60 MPH posted work zone limit.

[Ketchup99]

Pennsylvania:

20 - almost unheard of
25 - residential, very common
30 - sometimes residential, relatively uncommon
35 - default urban, very common
40 - rareish? Kind of like 30
45 - any highway with any amount of development, pretty much - very common
50 - quite rare
55 - Default and I hate it but common
60 - literally illegal
65 - About half of rural interstates, quite common
70 - The other half of rural interstates, also quite common
75 - can we have these, please?
80 - Dreamland

And if they wanted fewer people driving 40 because of depth perception issues... that's an excellent reason to abolish the 30mph speed limit. 

[ilpt4u]

Pennsylvania:

60 - literally illegal

Dumb question time: Why is a speed limit of 60 MPH illegal in the Keystone State?

[Great Lakes Roads]

Indiana-

Interstates: 50 mph (Indianapolis in downtown) 60 mph speed limits (Evansville and right before the bridges in Louisville)
Divided highways: I don't know...
Two-lane highways: 50 mph speed limits (it's only used in busy stretches with a lot of driveways)

[Ketchup99]

Pennsylvania:

60 - literally illegal

Dumb question time: Why is a speed limit of 60 MPH illegal in the Keystone State?

I've got a dumb answer. The highest allowable speed limit was - and still is, in most cases - 55mph until 1995. The legislature then passed a law permitting a 65mph limit on freeways, and then in 2013, they allowed a 70mph limit. But to this day, it is legal to post any speed up to 55, or it is legal to post 65, or it is legal to post 70. And many roads which would benefit from a 60mph limit (some desolate two-laners that should be 70 but the legislature would never, most rural divided highways that should also be 70 but the legislature would never, some urban highways...) are stuck at 55.

I believe many Northeastern states (NJ comes to mind) are in a similar predicament.

[jp the roadgeek]

In CT, RI, NH, VT, NY, and NJ, 60 MPH zones do not exist.  MA only has one to my knowledge (MA 3), and Maine only has a couple. It took almost 20 years for CT to add to its initial list of 65 MPH zones that were established in 1998 (two stretches of I-84 between Cheshire and Farmington were finally raised to 65 in 2018).  A few stretches could be raised to 60 MPH such as CT 8 between the CT 25 split and Naugatuck, CT 25 north of the split, SR 695, much of the Merritt and Wilbur Cross Parkways, and the CT 15 expressway (once the I-91 interchange project is completed).

[webny99]

60 seems like the obvious choice if you're looking primarily at the Northeast, but many Midwestern states use 60 for their urban freeways.
I'd say 50 is a better choice: Most places have some 50 zones, but there's nowhere where they're particularly prevalent.

It might be a good idea to first decide which ones can be eliminated: 30, 55, 65, probably 75. And personally, I'd say both 35 and 40 are out, as those are both very common in suburban areas. Any others?