CHICAGO – President Bush signed the $286.5 billion transportation bill yesterday, saying it would ease traffic congestion throughout America, create hundreds of thousands of jobs, and impose stricter vehicular-safety standards that will save lives.

But critics said the legislation was stuffed with unnecessary and expensive projects that benefited only members of Congress seeking hometown support.

The six-year bill, the first major transportation spending measure since 1998, pays for projects from fiscal years 2004 through 2009. The previous highway bill expired September 30, 2003, and Congress repeatedly passed funding extensions for current projects until it could agree on new legislation.

After years of delay over the amount of spending and the division of funds among states, the bill cleared the House and the Senate last month by large bipartisan votes. But some lawmakers and government watchdog groups expressed outrage over the number of individual projects – more than 6,000 – in the legislation.

The bill’s price tag was $2.5 billion higher than Mr. Bush had requested.

“Our economy depends on us having the most efficient, reliable transportation system in the world,” Mr. Bush said during the signing ceremony at a Caterpillar Inc. plant in Montgomery, Ill., about 40 miles west of Chicago.

But “highways just don’t happen,” the president said. “People have got to show up and do the work to refit a highway or build a bridge, and they need new equipment to do so. So the bill I’m signing is going to help give hundreds of thousands of Americans good-paying jobs.”

He described the legislation as “more than a highway bill; it’s also a safety bill” – an assessment with which Joan Claybrook, a longtime auto safety advocate, agreed.

Ms. Claybrook said the bill’s provisions “could produce the most significant safety enhancement since air bags were required” in the 1991 highway bill and will “literally save thousands of lives and prevent untold suffering.”

The biggest effect, she said, will come from addressing the two deadliest types of accidents, rollover and side-impact crashes, which kill about 20,000 people each year and injure more than 17,000.

The legislation requires the National Highway Traffic Safety Administration to create a stability standard designed to prevent rollovers by April 2009 and to update its 34-year-old roof strength standards, Ms. Claybrook said.

“This law makes our highways and mass transit systems safer and better, and it will help more people find work,” Mr. Bush said.

One of the biggest critics of the bill was Senator McCain, a Republican of Arizona and one of only four senators who voted against it. He said the estimated $24 billion lawmakers directed to special projects was “egregious.”