road widening with no superelevation
road widening with no superelevation
(OP)
Due to restrictions, I am to design a road with a 500' radius curve and an 800' reverse curve. Our client does not want superelevation because of the possibility of commercial development adjacent to the road.
What is the maximum design speed that I can obtain assuming only a normal crown of 2% slope?
What is the maximum design speed that I can obtain assuming only a normal crown of 2% slope?





RE: road widening with no superelevation
Be advised that you can expect to have increased numbers of head-on and run-off-road crashes due to insufficent super. Can you at least talk your client into a reverse crown?
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"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."
Wm. Phelps Eno, ca. 1928
RE: road widening with no superelevation
RE: road widening with no superelevation
RE: road widening with no superelevation
Imagine having to do the job you're being paid to do!
RE: road widening with no superelevation
RE: road widening with no superelevation
i am not american, just european or dutch if you want to know
RE: road widening with no superelevation
RE: road widening with no superelevation
"A Policy on Geometric Design of Highways and Streets" published by the FHWA.
This is the primary reference for road design in the United States.
RE: road widening with no superelevation
RE: road widening with no superelevation
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"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."
Wm. Phelps Eno, ca. 1928
RE: road widening with no superelevation
RE: road widening with no superelevation
we have guidelines for every kind of roads separated.
Tons of them
RE: road widening with no superelevation
RE: road widening with no superelevation
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"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."
Wm. Phelps Eno, ca. 1928
RE: road widening with no superelevation
Yes it was 1984 when they combined the Blue (rural) and Red (urban) manuals.
I was just out of school and my first position was with a state DOT; We started getting the new books in early '85 I think.
I can't tell you how many oldtimers were really bothered that the combined manual was green instead of purple. Mostly it took the form of muttering something like "Why did AASHTO do something so illogical? You combine red and blue, you get purple, not green."
RE: road widening with no superelevation
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"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."
Wm. Phelps Eno, ca. 1928
RE: road widening with no superelevation