Also, in one of the world's largest and densest cities, there is simply no space for larger, straighter roads. Widening some highways even a little might involve seizing and razing thousands of houses and apartment buildings.

"The idea of replacing a parkway probably isn't realistic," said Gerry Bogacz, the Transportation Council's planning director. "It becomes a huge undertaking to even do something as simple as straightening a road, in a place where there might be a curve."

But there are things that can, and are, being done, he said.

The Bronx River Parkway bridge that was the scene of April 29 crash is scheduled to be rebuilt in the next few years. After the crash, state transportation officials said they would install new concrete barriers on the viaduct, and two others nearby, in an attempt to better guard against vehicles going off the edge of the road. There is a railing on the bridge, but the family's Honda Pilot hit a curb and vaulted over it onto the grounds of the Bronx Zoo. There were no open exhibits in the area where the SUV fell.

A funeral for the seven killed members of the family was held Friday.

Hundreds of other similar road projects are taking place on major roads and highways around the city. On surface roads, New York City officials have attacked the larger problem of pedestrian and cyclist deaths by adding bike lanes and creating more pedestrian-friendly plazas and sidewalks.

"This is the stuff that keeps New York going," said the Transportation Council's spokeswoman, Lisa Daglian. "Are they sexy? Not necessarily. But do you notice if they are not done? Absolutely."

Most of the biggest-ticket transportation projects happening in the city right now involve expanding the rail network, including two expensive expansions of Manhattan subway system, reconstructing a light rail station destroyed in the Sept. 11 attacks, and a new underground line connecting the city's two main train stations.