Ive never been on this road, but ive seen Pictures (http://www.houstonfreeways.com/modern/2007-01-08_fm170.aspx).
I had the pleasure of driving FM 170 three years ago, and it was great. Easily one of the coolest roads I've ever driven.
This is my favorite FM 170 picture (taken late December 2001):
http://winklers-roads.fotopic.net/p9008103.html (http://winklers-roads.fotopic.net/p9008103.html)
Many (not all) of the pictures in this gallery are from FM 170.
http://winklers-roads.fotopic.net/c337179.html (http://winklers-roads.fotopic.net/c337179.html)
I really would like to go back to Big Bend National Park.
I've always wondered where they came up with 58420 pounds as a seemingly standard weight limit. It's not an even multiple of metric tons (2200 pounds).
I don't know the answer to that one. The sign is R12-1T in the regulatory signs chapter of Standard Highway Sign Designs for Texas (http://www.dot.state.tx.us/txdot_library/publications/highway_signs.htm) and the design for it does say "58420," but in keyline, implying that the precise limit can be varied to match the actual load capacity of the structure. My best guess is that 58420 pounds is based on a particular type of slab-and-post construction which was standardized and used (probably to excess) on FM and RM roads in pre-Interstate (possibly pre-World War II) days.
I remember seeing a similar number in Mississippi. Might be the same number, but I could've sworn the Miss. standard had a 7 in it. It was around 60,000 as well.
Quote from: J N Winkler on September 24, 2009, 01:22:03 PM
This is my favorite FM 170 picture (taken late December 2001):
http://winklers-roads.fotopic.net/p9008103.html (http://winklers-roads.fotopic.net/p9008103.html)
Many (not all) of the pictures in this gallery are from FM 170.
http://winklers-roads.fotopic.net/c337179.html (http://winklers-roads.fotopic.net/c337179.html)
I really would like to go back to Big Bend National Park.
Id like to go back to Big Bend also!
BigMatt
Quote from: J N Winkler on September 24, 2009, 05:10:37 PM
I don't know the answer to that one. The sign is R12-1T in the regulatory signs chapter of Standard Highway Sign Designs for Texas (http://www.dot.state.tx.us/txdot_library/publications/highway_signs.htm) and the design for it does say "58420," but in keyline, implying that the precise limit can be varied to match the actual load capacity of the structure. My best guess is that 58420 pounds is based on a particular type of slab-and-post construction which was standardized and used (probably to excess) on FM and RM roads in pre-Interstate (possibly pre-World War II) days.
I was looking it up as well. Apparantly when most of these roads were first being paved, 58,420 was a standard GVW (Gross Vehicle Weight), so it was made a standard weight rating for the roads (just like most roads now have an 80,000 GVW). Of course, roads or bridges can handle much more, but consistently taking that beating will wear the road/bridge out faster. However, most loads can get a permit to carry much heavier loads on the roads if needed. The absolute 'failure weight' of a road or bridge is probably much higher than even they'll admit.
The problem with most FM roads I've encountered in Texas is that they don't seem to A) have a solid base under the blacktop and B) not really wide enough for an 8'6 wide vehicle to pass each other.
Either way, most know that 58420 is a Texas standard. Besides, unless someone is actually weighing every truck that goes down the road, there's nothing to stop overweight trucks from taking the road.
Sykotyk
Quote from: Sykotyk on October 01, 2009, 04:15:34 PM
The absolute 'failure weight' of a road or bridge is probably much higher than even they'll admit.
probably around this much:
http://graphics1.snopes.com/photos/accident/graphics/housebridge2.jpg (http://graphics1.snopes.com/photos/accident/graphics/housebridge2.jpg)
Can't hotlink snopes, apparently. But I know the story you're talking about. They were moving the house in Canada and the DOT-esque agency accidentally routed them down the wrong back road to its final destination?
That's a matter of weight per axle. Hardly any bridge would stand up to that. Even on major bridges the decking can't support it. That's why the super loads (i.e., those behemoths weighing in at 80-160 TONS have an ungodly number of axles, huge pilot/escort teams to block roads to make sure that vehicle is the only thing on the bridge at a time, and exact times they're allowed to move, for how long, what speed, etc) must get their axle weights to a somewhat reasonable weight so as to not warp/crush/shatter the bridge as it crosses over. Plus, most truck tires can't stand too much weight. Most probably can only handle about 5-6,000 pounds each. Love seeing those trucks with 20+ axle trailers, 8 wheels per axle, helper truck in the back, creaping up a hill at 2mph with squad of escorts, police, and road service out assisting.
Sykotyk
Sykotyk