Ever-popular cul de sacs draw planners' frowns

People see the ideal family home as a place where the kids can play out front in the street, and the parents know the neighbors. For many, a spot on a cul-de-sac fills the bill.

French for bottom of the bag, the cul-de-sac ends a street in a dead end loop, rather than connecting to another through street.

But the design can cause problems. Communities in some parts of the country are restricting or even outlawing cul-de-sacs. The complaint? Congestion.

Because cul-de-sacs are dead ends, residents must get into cars to travel around the neighborhood. They go everywhere on other streets, in effect shunting the noise and exhaust of their vehicle passage onto other houses situated on through streets.

That's not a problem in large, spacious suburban parks. But it can be when introduced into older existing neighborhoods, says John Martini, engineering manager in the Sparks community development department.

"Atlanta is a great example of what not to do," says Martini.

There, clusters of new cul-de-sacs all dump onto existing streets where people already lived before current levels of congestion.

There is a movement back to grids and straight streets with stop signs, he says, called neotraditional design.

However, if collector streets are properly planned, cul-de-sacs don't matter, says Martini. Because an average street is not allowed to load over 2,000 trips per day.

"In Sparks we've done a lot to prevent congestion," he says. "And we require sidewalks."

The city also limits cul-de-sacs to 1,000 feet long. At the back, a hedgerow is required, with a sidewalk at the top of the bulb leading to trails behind it.

The fire department gets concerned about the length of cul-de-sacs and the size of the bulb, so Sparks requires the turn-around loop to measure 100 feet in diameter.

Generally, cul-de-sac streets measure 45 to 55 feet wide, compared with through streets, which are 55 to 60 feet wide.

The average cul-de-sac holds four to five houses on the bulb and another 12 on the straight part. A longer 1,000- foot drive can accommodate 33 houses.

People pay a premium to live on a cul-de-sac, says Barron Caronite, engineering manager at the City of Reno.

And Caronite adds that the hammerhead is a second way to terminate a street. Rather than ending a circle, the road goes into a box, in effect a shared driveway. The residents are responsible for removing snow fortunate, because large plows may not be able to turn around in a hammerhead. And if a fire truck is called, it must park in the street and drag in a hose, says Caronite.

A hammerhead is designed to increase the density of homes. That results in a smaller front yard.

Meanwhile, on a cul-de-sac, the lots are bigger, especially the back yards that fan out into a Y shape, says homeowner Consuelo Beach in the University Ridge area of north Reno.

"We chose a cul-de-sac deliberately because we had pets and didn't want the drive through traffic," she says. "Plus, on a cul-de-sac, the houses face each other, so the neighbors are friendlier. They get each other's mail. Cul-de-sacs are by far preferable."