Lowest speed limit on an Interstate?

[tidecat]

I believe the tunnel for I-10 in Mobile is signed as 35 MPH, but I haven't been through that in ages.

[Laura]

I-83 in downtown Baltimore is 40 mph. I think the changeover is just north of Guilford Ave.


iPhone

[sawblade5]

The lowest Speed Limit on a Interstate I saw personally is the Truck Speed Limit of 25 MPH on I-376 (Former I-279) heading towards the Fort Pitt Tunnel towards Downtown Pittsburgh, PA. https://goo.gl/maps/vJ3Pb The sign I linked is just a couple of miles out from the Tunnel as the freeway goes down a steep grade. There's even a runaway truck ramp on this stretch of highway just down the road from this pic.

[robbones]

I 59 in Laurel, Mississippi had a 40 mph at the former S curve. I'm not sure if it's still that slow since they realigned the road.

[Mark68]

Are we counting I-180 in Cheyenne?

It's posted at 40 mph.

[Pete from Boston]

Are we counting I-180 in Cheyenne?

It's posted at 40 mph.

SLD has the surface portion of I-78 in Jersey City at 25mph.

[cl94]

Are we counting I-180 in Cheyenne?

It's posted at 40 mph.

SLD has the surface portion of I-78 in Jersey City at 25mph.

As if you could ever go that fast on the tunnel approach. You're lucky to do 10 most of the time.

[Pete from Boston]

Are we counting I-180 in Cheyenne?

It's posted at 40 mph.

SLD has the surface portion of I-78 in Jersey City at 25mph.

As if you could ever go that fast on the tunnel approach. You're lucky to do 10 most of the time.

Upthread I said it has a tacit speed limit of 15, but that's at 4 in the morning. 

[bing101]

Speed Limit 50. Thats for the Western Terminus for I-80 in San Francisco. This is the slowest Speed Limit for an interstate in California.

[pianocello]

The lowest Speed Limit on a Interstate I saw personally is the Truck Speed Limit of 25 MPH on I-376 (Former I-279) heading towards the Fort Pitt Tunnel towards Downtown Pittsburgh, PA. https://goo.gl/maps/vJ3Pb The sign I linked is just a couple of miles out from the Tunnel as the freeway goes down a steep grade. There's even a runaway truck ramp on this stretch of highway just down the road from this pic.

The Truck speed limit on the Mackinac Bridge (I-75 Michigan) is 20. Not sure if that counts, though, as the car speed limit is 45.

[Fred Defender]

25 MPH (advisory) speed limit for I-75 north transitioning from the Fisher Freeway to the Chrysler Freeway in Detroit:

https://maps.google.com/maps?q=Chrysler+Freeway,+Detroit&hl=en&ll=42.342266,-83.045676&spn=0.004447,0.004265&sll=37.269174,-119.306607&sspn=13.851002,17.468262&t=h&hq=Chrysler+Freeway,&hnear=Detroit,+Wayne,+Michigan&fll=42.342365,-83.0453&fspn=0.004447,0.004265&z=18&layer=c&cbll=42.341914,-83.045669&panoid=WMDMiMES1K6xA4x4WKhuNA&cbp=12,105.55,,1,-8.04

Advisories are not limits.

My rule of thumb on advisory signs - developed while tearing around the North Georgia mountains in a 1990 Toyota MR2: Double and add 10.

So 60 it is at the Fisher/Chrysler transition in Detroit.

[bzakharin]

My rule of thumb on advisory signs - developed while tearing around the North Georgia mountains in a 1990 Toyota MR2: Double and add 10.

So 60 it is at the Fisher/Chrysler transition in Detroit.

So I can go 110 on the Atlantic City Expressway at the curve approaching its western terminus?

[Bickendan]

Sure... 110 kmh.

[SteveG1988]

What about bridges with changable speed limits? I don't know how low the bridges near philly can go, but 35 seems to be normal.

[jeffandnicole]

What about bridges with changable speed limits? I don't know how low the bridges near philly can go, but 35 seems to be normal.

25 mph in severe weather conditions.

[SteveG1988]

What about bridges with changable speed limits? I don't know how low the bridges near philly can go, but 35 seems to be normal.

25 mph in severe weather conditions.

In theory these roads can go down to 5mph, so i would say that is the lowest.

[vdeane]

Can we count toll plazas?  If so, numerous NY interstates have 5 mph speed limits (the speed limit of most Thruway E-ZPass-only lanes) at most toll barriers.

[admtrap]

Speed Limit 50. Thats for the Western Terminus for I-80 in San Francisco. This is the slowest Speed Limit for an interstate in California.

(Truck) Speed Limit 35 on NB I-5 through the Grapevine coming down from Tejon Pass says hi.

But 50 probably is the slowest regular automobile speed limit for a CA Interstate, so I'll concede that.

[jeffandnicole]

What about bridges with changable speed limits? I don't know how low the bridges near philly can go, but 35 seems to be normal.

25 mph in severe weather conditions.

In theory these roads can go down to 5mph, so i would say that is the lowest.

In theory, yes.  But the actual lowest posted speed I've seen or heard is 25 mph.