Road's that keep the same speed limit for their entire length

[Flint1979]

As I was traveling down McCarty Road in Saginaw Township I realized that the speed limit is 45 all the way from North Michigan Road to Midland Road and wondered how many other roads could fit this bill. This road is 7 miles long and is two lanes for its entire length as well.

[TheHighwayMan3561]

Around here
I-494 (42 miles) and I-694 (31): 60 MPH
I-535 (2 miles): 55 MPH - the 30 zone doesn't begin until after the south end

[pdx-wanderer]

I believe all three I-405s fit this criteria. California 65 mph for 72 miles, Oregon 50 mph for 4 miles, and Washington 60 mph for 30 miles.

I-86 in Idaho with 80 mph for 63 miles would be another.

[jp the roadgeek]

I-291 and I-691 in CT both are 65 MPH their entire length (except for the very end of each).  I-291 and I-391 in MA are 55 MPH the entire length.

I-395 in CT and MA is 65 MPH the entire length (and the 65 MPH speed limit continues on I-290 to the Worcester city line)

I-684 in NY and CT is 65 MPH the entire length (except for the portion near I-84 and the two southern legs).

Except for the portion through downtown Middletown, CT 9 is 65 MPH the entire length. 

[oscar]

AK 11 (Dalton Highway) is nominally posted for 50 mph for its entire 416-mile length:



However, there are some places you might want to slow down, like the narrow bridge over the Yukon River, or the switchbacks in the Atigun Pass area.

[pianocello]

It doesn't quite count, but I was surprised to find out that I-75 in Florida has speed limit 70 for its entire 470-mile length. The speed limit drops in other states, though.

I-474 and I-155 have a speed limit of 70 for their entire length. To find other examples in the Midwest, you'd just have to find a 2-lane road that begins and ends in the middle of nowhere and doesn't pass through any towns. The chances are pretty good that it'll have a 55-mph speed limit the whole way.

[ozarkman417]

By "Road", do you mean a route or a continuous road? Many lettered highways in Missouri have the same speed limit (55) throughout their lengths unless it enters some sort of city limits.

[wxfree]

There are quite a few rural FM/RM roads in Texas that begin and end at a highway or at a gravel road and pass through no towns, so they have high speed limits the whole way.  Here's a sample:

RM 2886 43 miles 70
RM 2083 36 miles 75
FM 2129 23 miles 75
RM 1312 13 miles 75
RM 2398 15 miles 75
FM 3078 15 miles 75
RM 652  59 miles 75
FM 1450 44 miles 75
FM 1233 34 miles 75
RM 2034 28 miles 75

[US 89]

I-86 in Idaho with 80 mph for 63 miles would be another.

I'm 98% sure it drops to 65 mph as it enters Pocatello.

[sprjus4]

In Virginia...

One speed, no exceptions -
I-664 is consistently posted at 60 mph.
I-564 is consistently posted at 55 mph.
VA-168 Chesapeake Expressway is consistently posted at 55 mph. (not counting the toll plaza area)
I-195 is consistently posted at 55 mph.
VA-195 is consistently posted at 55 mph. (not counting the toll plaza area)
VA-288 is consistently posted at 65 mph.
I-581 is consistently posted at 55 mph.
I-381 is consistently posted at 55 mph.

Mostly one speed, though one exception -
I-464 is consistently posted at 60 mph - with the exception it lowers to 45 mph on the northern end approaching the Downtown Tunnel / Berkley Bridge Complex.
I-264 is consistently posted at 55 mph - with the exception it lowers to 35 mph in the middle through the Downtown Tunnel / Berkley Bridge Complex.
VA-895 is consistently posted at 65 mph - with the exception it lowers to 60 mph on the western end approaching I-95. (not counting the toll plaza area)
I-295 is consistently posted at 70 mph - with the exception it lowers to 65 mph in the middle through the I-95 interchange complex.
I-85 is consistently posted at 70 mph throughout Virginia - with the exception it lowers to 65 mph and 60 mph approaching its northern end.
VA-76 Powhite Pkwy is consistently posted at 60 mph - with the exception it lowers to 55 mph approaching its northern end. (not counting the toll plaza area)

[1995hoo]

^^^^

To the second category, I'd add that I-495's general-purpose lanes are posted at 55 mph all the way through Virginia (and Maryland too), but the HO/T lanes are posted at 65 for their whole length.

[sprjus4]

^^^^

To the second category, I'd add that I-495's general-purpose lanes are posted at 55 mph all the way through Virginia (and Maryland too), but the HO/T lanes are posted at 65 for their whole length.

Also, isn't the "Dulles Toll Road" portion of VA-267 posted consistently at 55 mph? I know the "Dulles Greenway" portion is 65 mph, but none on the "Dulles Toll Road" IIRC.

[sprjus4]

All of I-97 is consistently posted at 65 mph 

(which is surprising, especially around the Glen Burnie area where, using every other freeway in the area as an example, should be 55 mph)

[Rothman]

^^^^

To the second category, I'd add that I-495's general-purpose lanes are posted at 55 mph all the way through Virginia (and Maryland too), but the HO/T lanes are posted at 65 for their whole length.

Heh.  I-495 keeps the same speed limit through DC, too!

[sprjus4]

^^^^

To the second category, I'd add that I-495's general-purpose lanes are posted at 55 mph all the way through Virginia (and Maryland too), but the HO/T lanes are posted at 65 for their whole length.

Heh.  I-495 keeps the same speed limit through DC, too!

Which is funny because anytime I've driven I-495, especially the I-95 section in Maryland, everyone is doing at least 75 mph, if not 80+ mph. And it's not out-of-state drivers... it's all Maryland plates. It also comes with some reckless driving, weaving all over the 4-lanes, cutting people off, tailgating, and other usual Maryland driver traits.

55 mph is absurdly slow IMO, should be 65 mph minimum.

[LM117]

I-795 in North Carolina is 70mph.

[1995hoo]

^^^^

To the second category, I'd add that I-495's general-purpose lanes are posted at 55 mph all the way through Virginia (and Maryland too), but the HO/T lanes are posted at 65 for their whole length.

Heh.  I-495 keeps the same speed limit through DC, too!

Which is funny because anytime I've driven I-495, especially the I-95 section in Maryland, everyone is doing at least 75 mph, if not 80+ mph. And it's not out-of-state drivers... it's all Maryland plates. It also comes with some reckless driving, weaving all over the 4-lanes, cutting people off, tailgating, and other usual Maryland driver traits.

55 mph is absurdly slow IMO, should be 65 mph minimum.

I usually set my cruise control at 65 everywhere on the Beltway's general-purpose lanes, except in the work zone near Andrews AFB (slower there to hedge against speedometer error in a speed camera zone). I am always neither the slowest person nor the fastest person, so I figure that's a good speed to choose.

[Techknow]

Bay Area and California:

• I-40 in California has a limit of 70 MPH throughout the freeway, so does I-505.
• At more than 57 miles, I believe I-280 would be the longest urban route in the Bay Area for this, it is always 65 MPH from San Jose to San Francisco. I believe there are no speed limit signs a couple miles within the north end, the first one I seen going south is after US-101 junction where the freeway becomes 8 lanes.
• Nowadays I clinch I-380 every weekday in my commute but I have yet to see any speed limit sign on this short interstate stretch, I assume it is also 65 MPH
• CA 85 is always 65 MPH. I haven't driven on it north of CA 237 so it could differ there.
• CA 153, signed as "California's shortest state highway" for about half a mile, has a speed limit of 25 MPH.

[roadman65]

Is I-195 in NJ all 65 mph? 
In FL all of SR 62 is 60 mph from US 17 to US 301.

[PHLBOS]

Is I-195 in NJ all 65 mph?

The westernmost mile-and-a-half drops down to 55.

[royo6022]

It doesn't quite count, but I was surprised to find out that I-75 in Florida has speed limit 70 for its entire 470-mile length. The speed limit drops in other states, though.

I-474 and I-155 have a speed limit of 70 for their entire length. To find other examples in the Midwest, you'd just have to find a 2-lane road that begins and ends in the middle of nowhere and doesn't pass through any towns. The chances are pretty good that it'll have a 55-mph speed limit the whole way.

Ha. We all know no one goes 70 in I-75 in Florida though - every time I go down there the minimum speed is 85 on I-75, and its almost exactly when you cross into Florida when it starts to be that way.

[michravera]

Bay Area and California:

• I-40 in California has a limit of 70 MPH throughout the freeway, so does I-505.

Doesn't Westbound I-40 have an Agricultural Inspection Station which includes advisories eventually down to zero?
I-505, however, is pretty pure.

• At more than 57 miles, I believe I-280 would be the longest urban route in the Bay Area for this, it is always 65 MPH from San Jose to San Francisco. I believe there are no speed limit signs a couple miles within the north end, the first one I seen going south is after US-101 junction where the freeway becomes 8 lanes.
• Nowadays I clinch I-380 every weekday in my commute but I have yet to see any speed limit sign on this short interstate stretch, I assume it is also 65 MPH
• CA 85 is always 65 MPH. I haven't driven on it north of CA 237 so it could differ there.

There are some advisories on the merge on to US-101, but nothing posted as regulatory (and you may want to argue that CASR-85 ends before the advisories).

• CA 153, signed as "California's shortest state highway" for about half a mile, has a speed limit of 25 MPH.

[ftballfan]

In Michigan:
I-275 - 70 mph
I-475 - 70 mph
I-496 - 70 mph
M-6 - 70 mph
M-102 - 45 mph
M-231 - 65 mph

[tdindy88]

I wonder if one side of an interstate highway counts. The clockwise traveling segment of Interstate 465 in Indianapolis is 55 MPH the entire way. The counterclockwise lanes of the interstate are 55 MPH with the exception of the northwest corner where the interchange with I-865 forces the speed limit to go down to 45 before resuming 55 on the other side, traveling WB to SB. As far as I remember the clockwise section of the beltway (NB to EB) doesn't have to lower its speed rounding that corner.

Of course no one respects that speed limit.

[bing101]

Bay Area and California:

   
• I-40 in California has a limit of 70 MPH throughout the freeway, so does I-505.
• At more than 57 miles, I believe I-280 would be the longest urban route in the Bay Area for this, it is always 65 MPH from San Jose to San Francisco. I believe there are no speed limit signs a couple miles within the north end, the first one I seen going south is after US-101 junction where the freeway becomes 8 lanes.
• Nowadays I clinch I-380 every weekday in my commute but I have yet to see any speed limit sign on this short interstate stretch, I assume it is also 65 MPH
• CA 85 is always 65 MPH. I haven't driven on it north of CA 237 so it could differ there.
• CA 153, signed as "California's shortest state highway" for about half a mile, has a speed limit of 25 MPH.

I-505 has 70mph for the entire route and I-780 65mph for the entire route.