States that have minimum posted speed limits and what are they.

[ChoralScholar]

When the speed limit on the interstates went up from 55 to 65, Arkansas implemented a stacked sign that had 65 on top, and Minimum Speed 45 on the bottom.

Now that the SL has been raised to 70, the bottom sign reads Trucks 65.

[jeffandnicole]

I believe it was Colorado I was driving in recently that posts a minimum speed for the left lane (Minimum Speed 55).  If anything...I think it caused confusion!  I noticed a few times cars would slow down apporaching the sign, thinking the speed limit was going down. 

[kphoger]

This is not a state standard, but I thought Mexican minimum speed limit signs were rare enough to be of interest on this thread:

http://goo.gl/maps/Fbw5E

[agentsteel53]

This is not a state standard, but I thought Mexican minimum speed limit signs were rare enough to be of interest on this thread:

http://goo.gl/maps/Fbw5E

now that is a challenge to differentiate from a maximum sign offhand.  if I weren't carefully reading the words, my first instinct would be to think "120 cars, 80 trucks".

I wonder how well that is enforced.  I've seen donkey carts on Mexico freeways before! 

[kphoger]

This is not a state standard, but I thought Mexican minimum speed limit signs were rare enough to be of interest on this thread:

http://goo.gl/maps/Fbw5E

now that is a challenge to differentiate from a maximum sign offhand.  if I weren't carefully reading the words, my first instinct would be to think "120 cars, 80 trucks".

I wonder how well that is enforced.  I've seen donkey carts on Mexico freeways before! 

Usually not toll roads, though, to be fair...

[vdeane]

I'm guessing there's less of a difference between freeways and surface streets in Mexico than the US and Canada given that maps don't differentiate.

[kphoger]

I'm guessing there's less of a difference between freeways and surface streets in Mexico than the US and Canada given that maps don't differentiate.

What maps don't differentiate?  My atlas differentiates between divided highways, "supercarreteras", and regular old two-lane roads.  Tolled segments are marked with a "D" shield, and free ones are not.  An example of the cartography is here.  Maybe you need different maps.

But anyway, non-motorized traffic is much less common on toll roads.  Many of them even prohibit cyclists from using them.  Having personally driven part of the toll road that that sign is posted on, I would be very surprised to encounter non-motorized traffic on it.  However, I would be less surprised to encounter a vehicle travelling at less than the posted minimum.  Those speeds, in fact, are as high as those on Oklahoma's turnpikes–which have surprisingly high minimums.  80 km/h equates to 50 mph; there are a great many trucks in México that struggle to maintain that speed.  And, as the highway goes on toward the west, it encounters uphill grades steep enough to thwart even early-model, poorly maintained passenger vehicles.  Shoot, on some mountain roads in the area, even I struggle to maintain 80 km/h at all times.

[vdeane]

I can't think of any of the major online maps that get it right, though OSM comes VERY close (the issue here probably arising from the fact that not all freeways in Mexico have full access control, such as route 1 in Tijuana along the US border).

[kphoger]

Well, not differentiating and not getting it right are two different things.  I challenge you to find any mapping program that gets everything right.

[NE2]

I challenge you to find any mapping program that gets everything right.

http://www.google.com/mars/

[Scott5114]

black with white text on a speed limit sign is - theoretically, anyway - regulatory.  at least, in California, prior to 1971. 

as for minimum posted speed limit - yes, every state has one

0 MPH

But it's only 40 on non-tolled freeways.

[agentsteel53]

black with white text on a speed limit sign is - theoretically, anyway - regulatory.  at least, in California, prior to 1971. 

as for minimum posted speed limit - yes, every state has one

0 MPH

posted? 

even if you are backing up, your speed is greater than 0mph.  your velocity is negative, but we don't have velocity limits in this country, otherwise every yahoo with a physics degree would install a transmission backwards and do 95mph looking over his shoulder.

[agentsteel53]

http://www.google.com/mars/

fails to show the secret base where we faked the moon landing.

[kphoger]

http://www.google.com/mars/

fails to show the secret base where we faked the moon landing.

Also doesn't show any freeways at ALL.

[Alps]

http://www.google.com/mars/

fails to show the secret base where we faked the moon landing.

Also doesn't show any freeways at ALL.

also shows that mars is flat and infinitely repeating

[Brandon]

I'm guessing there's less of a difference between freeways and surface streets in Mexico than the US and Canada given that maps don't differentiate.

What maps don't differentiate?  My atlas differentiates between divided highways, "supercarreteras", and regular old two-lane roads.  Tolled segments are marked with a "D" shield, and free ones are not.  An example of the cartography is here.  Maybe you need different maps.

But anyway, non-motorized traffic is much less common on toll roads.  Many of them even prohibit cyclists from using them.  Having personally driven part of the toll road that that sign is posted on, I would be very surprised to encounter non-motorized traffic on it.  However, I would be less surprised to encounter a vehicle travelling at less than the posted minimum.  Those speeds, in fact, are as high as those on Oklahoma's turnpikes–which have surprisingly high minimums.  80 km/h equates to 50 mph; there are a great many trucks in México that struggle to maintain that speed.  And, as the highway goes on toward the west, it encounters uphill grades steep enough to thwart even early-model, poorly maintained passenger vehicles.  Shoot, on some mountain roads in the area, even I struggle to maintain 80 km/h at all times.

But, they're still lower than the highest posted minimum speeds in North America.  Those belong to Michigan, where the minimum speed must be 55 mph (88 km/h) on the freeways where the speed limit is posted for 70 mph.

[averill]

New Mexico has a minimum speed of 65 for the left lane of I-40 (maximum speed 75) west of Albuquerque.

Pennsylvania has a minimum 40, but does not post it for some reason.  You can't enforce it if you don't post it.

[jeffandnicole]

New Mexico has a minimum speed of 65 for the left lane of I-40 (maximum speed 75) west of Albuquerque.

Pennsylvania has a minimum 40, but does not post it for some reason.  You can't enforce it if you don't post it.

Sure you can.  One can be stopped on the many roads that has a statutory 55 mph limit without it being posted as well.

[cpzilliacus]

Crossed the  Potomac River recently on U.S. 301 (Gov. Harry Nice Memorial Bridge) and noticed the posted limit was 50 MPH (which it has been for a while), and a minimum speed of 40 MPH (which I had not noticed the last time I crossed there).

This may be the only segment highway in Maryland that currently has a minimum speed limit posted.

[Alps]

Crossed the  Potomac River recently on U.S. 301 (Gov. Harry Nice Memorial Bridge) and noticed the posted limit was 50 MPH (which it has been for a while), and a minimum speed of 40 MPH (which I had not noticed the last time I crossed there).

This may be the only segment highway in Maryland that currently has a minimum speed limit posted.

I want to say that I-895 SB has a minimum speed upon leaving I-95, but it may be work zone signing that I'm misremembering.

[1995hoo]

Crossed the  Potomac River recently on U.S. 301 (Gov. Harry Nice Memorial Bridge) and noticed the posted limit was 50 MPH (which it has been for a while), and a minimum speed of 40 MPH (which I had not noticed the last time I crossed there).

This may be the only segment highway in Maryland that currently has a minimum speed limit posted.

I want to say that I-895 SB has a minimum speed upon leaving I-95, but it may be work zone signing that I'm misremembering.

I remember when I was a kid the Harbor Tunnel Thruway (it wasn't I-895 at the time) had a posted minimum of 40 mph.

I noted last Saturday that the speed limit on I-695 in DC has been raised from 40 mph to 45 mph from I-395 to the work zone for the 11th Street Bridge project. Compliance with the higher speed limit was every bit as good as it was with the old limit.

[Alps]

Crossed the  Potomac River recently on U.S. 301 (Gov. Harry Nice Memorial Bridge) and noticed the posted limit was 50 MPH (which it has been for a while), and a minimum speed of 40 MPH (which I had not noticed the last time I crossed there).

This may be the only segment highway in Maryland that currently has a minimum speed limit posted.

I want to say that I-895 SB has a minimum speed upon leaving I-95, but it may be work zone signing that I'm misremembering.

I remember when I was a kid the Harbor Tunnel Thruway (it wasn't I-895 at the time) had a posted minimum of 40 mph.

I noted last Saturday that the speed limit on I-695 in DC has been raised from 40 mph to 45 mph from I-395 to the work zone for the 11th Street Bridge project. Compliance with the higher speed limit was every bit as good as it was with the old limit.

New thread idea: States where drivers obey work zone speed limits. I'm drawing a blank... (There are a handful of states, in the South for example, that don't reduce speeds automatically. That'd be the best place to look.)

[TCN7JM]

I know I-90 in South Dakota has a minimum speed limit of 45 mph posted entering the state from Minnesota, but I haven't seen it posted anywhere else on the entire highway.

[Brandon]

Crossed the  Potomac River recently on U.S. 301 (Gov. Harry Nice Memorial Bridge) and noticed the posted limit was 50 MPH (which it has been for a while), and a minimum speed of 40 MPH (which I had not noticed the last time I crossed there).

This may be the only segment highway in Maryland that currently has a minimum speed limit posted.

I want to say that I-895 SB has a minimum speed upon leaving I-95, but it may be work zone signing that I'm misremembering.

I remember when I was a kid the Harbor Tunnel Thruway (it wasn't I-895 at the time) had a posted minimum of 40 mph.

I noted last Saturday that the speed limit on I-695 in DC has been raised from 40 mph to 45 mph from I-395 to the work zone for the 11th Street Bridge project. Compliance with the higher speed limit was every bit as good as it was with the old limit.

New thread idea: States where drivers obey work zone speed limits. I'm drawing a blank... (There are a handful of states, in the South for example, that don't reduce speeds automatically. That'd be the best place to look.)

In Illinois, they're readily ignored by most folks.  Of course, this might be because Illinois insists on having a 24/7 45 mph work zone speed limit whether workers are present or absent.

[cpzilliacus]

Crossed the  Potomac River recently on U.S. 301 (Gov. Harry Nice Memorial Bridge) and noticed the posted limit was 50 MPH (which it has been for a while), and a minimum speed of 40 MPH (which I had not noticed the last time I crossed there).

This may be the only segment highway in Maryland that currently has a minimum speed limit posted.

I want to say that I-895 SB has a minimum speed upon leaving I-95, but it may be work zone signing that I'm misremembering.

As Hoo mentioned above, I-895 (in the pre-I-895 days, and perhaps (IIRC) after the shields went up) had a posted minimum speed limit, in particular on the northbound side after exiting the tunnel.  Like the Nice Bridge now, I think the posted limit was 50 MPH and the minimum was 40 MPH.

I do not recall having seen a minimum posted limit on Maryland's I-895 recently.

As an aside, the MdTA has (somewhat recently) raised the posted speed limit on I-895 between I-95 and Md. 295 from 55 MPH to 65 MPH.
Post Merge: July 07, 2013, 05:11:33 PM

Crossed the  Potomac River recently on U.S. 301 (Gov. Harry Nice Memorial Bridge) and noticed the posted limit was 50 MPH (which it has been for a while), and a minimum speed of 40 MPH (which I had not noticed the last time I crossed there).

This may be the only segment highway in Maryland that currently has a minimum speed limit posted.

I want to say that I-895 SB has a minimum speed upon leaving I-95, but it may be work zone signing that I'm misremembering.

I remember when I was a kid the Harbor Tunnel Thruway (it wasn't I-895 at the time) had a posted minimum of 40 mph.

I noted last Saturday that the speed limit on I-695 in DC has been raised from 40 mph to 45 mph from I-395 to the work zone for the 11th Street Bridge project. Compliance with the higher speed limit was every bit as good as it was with the old limit.

New thread idea: States where drivers obey work zone speed limits. I'm drawing a blank... (There are a handful of states, in the South for example, that don't reduce speeds automatically. That'd be the best place to look.)

Maryland has work zone speed limits on freeways  that are sometimes the same limit as the "normal" posted limit, but with camera enforcement (the enforcement vehicle is always a white Jeep SUV).  There's such a 65 MPH work zone limit on I-95 through the Md. 200/Contee Road/Md. 198 construction area right now.

A few years ago, there was a 55 MPH work zone (photo-enforced) on I-270 south of Urbana in Frederick County, where the normal posted speed limit has been 65 for quite a few years.  There were some pretty significant lane shifts for the redecking of the bridge that carries 270 over Bennett Creek. The work zones were in place when GSV imaged that section of the highway (here, but the project is now complete).

To answer your question, the  presence of photo enforcement does seem to get drivers to obey the posted limit.
Post Merge: July 07, 2013, 05:11:31 PM

I noted last Saturday that the speed limit on I-695 in DC has been raised from 40 mph to 45 mph from I-395 to the work zone for the 11th Street Bridge project. Compliance with the higher speed limit was every bit as good as it was with the old limit.

I find it very curious that D.C. has automated speed limit all over the streets and highways under its direct control, yet not once have I see any hint of automated enforcement in this work zone since construction got going several years ago.