DEATSVILLE – School bus driver George Caudle patiently waits until all his passengers are buckled in before pulling out of Pine Level Elementary School’s parking lot each afternoon.

But it doesn’t take long before a familiar sound ripples through the vehicle.

“I can hear them unclicking as we hit Highway 31” when the bus leaves the lot, Caudle said Wednesday.

Transportation and education officials are hoping kids will wait until reaching their destinations before unhooking the belts, which will be required nationwide in smaller school buses under a new rule spurred by the deaths of four Alabama students in a 2006 crash.

Along with equipping smaller buses with lap-and-shoulder seat belts for the first time, seat backs on all new buses will be raised to 24 inches – up from 20 inches – over the next three years.

The seat belts will only have to be installed in new buses weighing 5 tons or less, and the requirement will not take effect until 2011. These smaller school buses are already required to have lap belts, but not the safer, harness-style belts. There is no seat belt requirement for larger buses.

“The rules were last changed in the 70’s and this is the most significant change since then,” Deputy U.S. Transportation Secretary Thomas Barrett said.

Barrett and Gov. Bob Riley traveled to Pine Level Elementary, about 20 miles north of Montgomery, to make the announcement and were treated to a rock star’s welcome by hordes of students who cheered and held up hand-painted signs.

After going over bus safety tips with some of the kids, Barrett and Riley climbed aboard a bus with 12 schoolchildren who have been using the belts in Alabama’s pilot study.

Third-grader Justin Jackson had to help Barrett and Riley, who fumbled with the four-point belts that buckle across the chest and lap.

Riley, laughing, said Justin told them: “Don’t worry, it takes practice.”

Jacob Chandler, 12, said he was worried about the belts.

“If you were to flip over in a pond, the little ones might not be able to get the belt off and they might drown,” he said.

But Monessia Smith, another 12-year-old, said she supported them.

“They’re good. It keeps kids safe,” she said.

The study began after four Lee High School teens were killed in Huntsville on Nov. 20, 2006. Their school bus went over a highway overpass rail and plunged to a street below. Dozens were injured when they were flung from their seats.

“We asked the question at that time – would it have been safer if the students on the Huntsville bus had had seat belts?” Riley said. “We were amazed to find out that no one knew.”

Huntsville attorney Douglas Fees, who represents families of victims in suits against the bus manufacturer and designer for not having seat belts, said they hope “to keep this from happening to someone else.”

Transportation Secretary Mary Peters said she stopped short of requiring seat belts for larger buses because that could limit the number of children that can squeeze into seats, forcing some children to travel in ways that aren’t as safe, like riding in cars, walking or riding bikes.

School districts sometimes expect as many as three younger children to share a bus seat, but if there are only two belts installed per seat then fewer children can ride the bus.

Schools buy about 2,500 of the smaller school buses each year, the Transportation Department said. The buses seat about 16 to 20 students. Larger buses carry more than 50 students.

The Transportation Department estimates it will cost about $6.1 million a year to equip new, smaller buses with the three-point seat belts and higher seat backs, and $3.6 million a year to equip new, larger buses with higher seat backs.

Putting belts on buses will raise single bus prices about $10,000 to $13,000 while the higher seat backs will add about $125 per bus, department officials said. Schools will be able to use federal highway safety funds to help pay for retrofitting buses.

Jonathan Adkins, a spokesman for the Governors Highway Safety Association, opposes using additional federal funds for seat belts on school buses.

“Federal highway safety money is very limited and using that money to install seat belts on school buses isn’t supported by crash data,” Adkins said. “School buses are already an incredibly safe mode of transportation. We are more concerned about the areas surrounding schools and bus stops. States should not be pressured on this issue.”

About 25 million children travel to school on 474,000 school buses, according to the Transportation Department.

“There are only about six fatalities on school buses every year compared to about 41,000 motor vehicle deaths, but that’s little solace to a grieving parent,” Barrett said.