It's good for you

[tribdog]

New housing developments in this area are not allowed to be made of nothing but straight streets. For every n houses in a development there must be at least x cul-de-sacs. Why are cul-de-sacs being required now?

[Bartholomew]

Peace and quiet? You get less traffic in a cul-de-sac.

[tribdog]

that is incorrect.
the peace and quiet may be nice, but that is not why cul-de-sacs are required

[Bartholomew]

Oh, this was an actual brain-teaser? I don't know, to deny enemy airplanes landing strips?

[tribdog]

It's sort of a brain teaser, because when I heard the answer I said wow, makes sense, why didn't I think of that

[Bartholomew]

Been looking online and the main other positive thing they say about cul-de-sacs is they promote car use.

[Gokul43201]

This is not related to the danger of terror attacks, is it ?

[tribdog]

I don't even know for sure if my answer is the correct one, but I was told by a life flight helicopter pilot that cul-de-sacs are required to make sure there is always a nearby place that a helicopter can land.

[check]

Oooo...makes sense... sort of.
When I used to live on a cul-de-sac people sued to park in the middle all the time though. And forget about winter, there was allways a massive snow hill on the centre that the snow plows made. That'd be neat to see a helicopter try to land on that.

[Bartholomew]

Did you know that every fifth mile of federal highway must be straight to provide landing strips for airplanes in case of emergency?

[DaveC426913]

10:10
Well, I assumed it was more of a math/geometry/topology problem.

i.e. If there are bendy streets, maybe it's impossible to lay out a pattern that has lots the same size without some of the streets being dead-ends.

10:14
Wait a minute. "For x houses". All the bendy streets will have more houses on one side than the other (unless they curve twice, cancelling out). Cul-de-sacs make up the difference, since they provide more hourse per unit of street than a regular house does.

I think I'm on the right track, but I don't have it yet.

10:17
No, it can't be right, it still would have had to stipulate some constraint on the lot sizes/shapes, wouldn't it?

10:18
Unless can be just assumed that, in a new housing development, all lots are designed to have the same area (if not the same shape).

10:19
Nope, still doesn't work. You can always make the lots the same area if you don't have to worry about the shape. You can make em longer and narrower.

10:20
Oh wait. Tribdog already provided the answer.
Um. Nevermind.

[BobG]

Did you know that every fifth mile of federal highway must be straight to provide landing strips for airplanes in case of emergency?
That's a common misconception. Here's an article from Richard Weingroff, an information liason specialist with the Federal Highway Administration. (He seems awful touchy for an information liason specialist. Not only does he hate it when people ask him about the emergency landing strips, he hates it when people ask him what an information liason specialist is).

http://geography.about.com/gi/dynamic/offsite.htm?site=http://www.tfhrc.gov/pubrds/mayjun00/onemileinfive.htm

If you think about, you would need more than just a straight stretch of road. You'd also need that stretch to be free of obstructions like overpasses, signs, and telephone poles.

I don't know about the helicopter landing area requirement, but that sounds a little iffy, as well.

[Gokul43201]

By the way, cul-de-sacs are actually going out of favor among urban developers. The primary reasons for them were relevant in the 50s and 60s. Not so much anymore. Traditional Neighborhood Design (TND) will be back.

[check]

By the way, cul-de-sacs are actually going out of favor among urban developers. The primary reasons for them were relevant in the 50s and 60s. Not so much anymore. Traditional Neighborhood Design (TND) will be back.

That's a shame. Cul-de-sacs are the best places to live IMO.

[Bartholomew]

That's a common misconception.
Oh, darn. You know, I got that from the NY Public Library desk reference calendar. A myth with aspirations of upward mobility, it seems.