Sudden Headaches - Unexpected Low Clearance on Major Interstates

[MN_Traveler]

I was looking through my Iphone Allstays camping App ... and was surprised to find it reporting a 13'4" clearance on I90 in Oakton SD. I was through there a number of years ago, but in a smaller rental uint, and do not remember a low clearance like that - but it was not as tall a unit as my current DP. My current unit has a (reported) clearance of 12'6", so coming up unexpectedly at highway speeds on a clearance like 13'4" would scare the *&^%$! out of me. In people's travels down the road on major interstates, how often have you run across clearances that left you cringing as you zoomed under the overpass??? (and, ESPECIALLY, has anyone run across a clearance (again on a major interstate) that would not allow the typical DP height to pass at all??? (from previous threads, I recall the 12"6" height is pretty typical of most DPs....)

[BFlinn181]

I'd say Allstays is wrong. Here's a list of South Dakota bridge heights. On a quick scan of the I-90 bridges, lowest clearance was 14'8" (pg. 25)
http://www.sdtruckinfo.com/docs/Vertical_Clear_List.pdf
Looking on Google maps, satellite view, there are only two bridges across I-90 on either side of Oakton, SD for many miles. Street view shows NO clearance signs or warnings on either of those bridges.
Federal Interstate Hwy regulations require a minimum clearance of 16' on rural interstates, 14' on urban. Oakton is hardly urban.

[FlyingDiver]

Originally Posted by BFlinn181

Federal Interstate Hwy regulations require a minimum clearance of 16' on rural interstates, 14' on urban. Oakton is hardly urban.

Unless otherwise marked, I believe that is. That is, if it's less than those heights there must be warning signs.

I know there are some interstates with overpasses that I can't take my RV under, and I need to take the ramp and go up the exit and back down the entry ramp. There's at least one on I-87 southbound, north of Albany NY (The Northway).

[lllkrob]

I just checked my "Low Clearance" file in Street & Trips and it does not show any low clearances anywhere along I-90 in South Dakota.

[BFlinn181]

I was weakly implying that anything below required clearances would be marked with warning signs, that's why I mentioned using Google Street View on the overpasses. Maximum height for trucks is 13'6", except car carriers, they are allowed 14'. Don't rely on Apps or GPS to save your rooftop accessories, keep your eyes open for warning signs, specially on older railroad bridges and roadways. I've experienced enough wrong info on GPS data bases I still use paper maps and atlas when navigating a new area.

[U-2 Pilot]

Originally Posted by MN_Traveler

I was looking through my Iphone Allstays camping App ... and was surprised to find it reporting a 13'4" clearance on I90 in Oakton SD. I was through there a number of years ago, but in a smaller rental uint, and do not remember a low clearance like that - but it was not as tall a unit as my current DP. My current unit has a (reported) clearance of 12'6", so coming up unexpectedly at highway speeds on a clearance like 13'4" would scare the *&^%$! out of me. In people's travels down the road on major interstates, how often have you run across clearances that left you cringing as you zoomed under the overpass??? (and, ESPECIALLY, has anyone run across a clearance (again on a major interstate) that would not allow the typical DP height to pass at all??? (from previous threads, I recall the 12"6" height is pretty typical of most DPs....)

Traveler has it right as far as what Allstays is showing on I90 in SD. Two overpasses at 13'10" & one at 13'4". As already mentioned this has to be an error.

[MN_Traveler]

Yeah - sounds like Allstays must be in error. Thanks for the confirmation folks - I did not **think** it should be common to find something that low on an interstate!

[demoon]

It must be emphasized that the integrity of the Interstate System for national defense purposes be maintained to meet AASHTO Policy as stated in A Policy on Design Standards - Interstate System, incorporated by reference in 23 CFR 625. On Interstate sections in rural areas, the clear height of structures shall be not less than 4.9 meters (16 feet) over the entire roadway width, including the usable width of shoulder. On Interstate sections in urban areas, the 4.9-meter (16-foot) clearance shall apply to a single routing. On other Interstate urban routes, the clear height of structures shall be not less than 4.3 meters (14 feet). Design exceptions must be approved whenever these criteria are not met.

[t55watson]

Are you kidding me? Have you EVER seen semi's take a ramp to avoid an overpass/ it is not a prob for RV's we are shorter than most semi's.

[FlyingDiver]

Originally Posted by t55watson

Are you kidding me? Have you EVER seen semi's take a ramp to avoid an overpass/ it is not a prob for RV's we are shorter than most semi's.

Yes I have.

And my rig is 13' 4". So not many trucks taller than me.

[GKW]

I drove through there just ahead of the big October storm with my 12'11" rig, and never had any concerns, but if I had seen a clearance of 13'4" I surely would have.

[gruelens]

If you are 13'6" or lower you will be fine on the Interstate Hwy System. There are some overpasses that are less clearance on the shoulder of the road. Some trucker GPS's will attempt to steer you around these locations. As long as you stay in the marked lanes of travel there are no problem. As stated earlier most van/box semi trailers are 13'6".

[JFXG]

The AITA (American Independent Truckers Assn) website ( aitaonline.com )features a low-clearance database listed by state. It specifically lists any road they're aware of with any clearance lower than 13' 6". The database shows no entry for any low clearance on any interstate in South Dakota, and no entry for any low clearance on I-87 in New York.

[badboy368]

Originally Posted by MN_Traveler

I was looking through my Iphone Allstays camping App ... and was surprised to find it reporting a 13'4" clearance on I90 in Oakton SD. I was through there a number of years ago, but in a smaller rental uint, and do not remember a low clearance like that - but it was not as tall a unit as my current DP. My current unit has a (reported) clearance of 12'6", so coming up unexpectedly at highway speeds on a clearance like 13'4" would scare the *&^%$! out of me. In people's travels down the road on major interstates, how often have you run across clearances that left you cringing as you zoomed under the overpass??? (and, ESPECIALLY, has anyone run across a clearance (again on a major interstate) that would not allow the typical DP height to pass at all??? (from previous threads, I recall the 12"6" height is pretty typical of most DPs....)

federal dot law says all federal and state roads are to be 13'6" but always keep your eyes open because there may be a detour posted for low clearance