Proper contouring of cul-de-sac 1

They are not easy. The best solution that I have found is to run the crown of the roadway into the island of the cul-de-sac. That way the water always stays in the gutter line. This only works well if you have at least one inlet in the cul-de-sac, two are better.

I should add that the cul-de-sac is intended to be a "temporary" installation (less than 5 years) until the next phase of the road can be built. Therefore, islands and drainage structures are being avoided.

In that case make sure that the "through" portion is constructed correctly, i.e. is a good running grade and proper cross slope. The remainder of the pavement should be constructed to drain down the main street or a temporary structure should be added.

Since it is a cul-de-sac and vehicle speeds should be low, it should be ok as long as it drains, so go ahead and grade the future through street as it should be.

It will also make it harder for homeowners to claim they were never informed that their nice quiet dead end was intended to be a through street if you build it so it is is obviously meant to go through. NY Times recently ran an article on this. Read it before it's too late (they make you pay to read articles over a week old).


"...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

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

Fortunately we don't have to worry about homeowners since it is not a residential street. But I like the idea of just grading the through street as it should be and just continuing that cross-slope all the way across the cul-de-sac.