Casper, Wyo. ? Sixteen-year-old Kaytie Christopherson was getting ready to do her homework on a Friday when she got a call that made a big improvement in her life: She had won a brand-new pickup truck for near-perfect school attendance.

And not just any truck, but a $28,000 Chevrolet Colorado crew cab, in red, with an MP3 player. Freedom comes standard.

Public schools commonly reward excellent attendance with movie tickets, gas vouchers and iPods. But some diligent students like Kaytie are now hitting the ultimate teenage jackpot for going to school: They have won cars or trucks.

School districts in Hartford, Conn.; Pueblo, Colo.; South Lake Tahoe, Calif.; and Wickenburg and Yuma, Ariz., are also giving away vehicles this school year.

In most cases the car or truck is donated by a dealership, and the prizes typically are awarded through drawings open only to students with good attendance.

So does bribing students with the possibility of winning a car or truck actually get them to think twice about staying home from school? Some educators think so, and say their giveaways have boosted attendance. But the evidence is not clear-cut.

Kaytie won her truck last spring in the school system’s first such drawing. But she said that was not what motivated her to keep up her attendance; she just didn’t want to fall behind.

Jack Stafford, associate principal at South Tahoe High School, said attendance increased slightly last year, the first year the school system gave away a car, and is up slightly so far this year. He said changing times call for such incentives.

“My mom had the three-B rule: There’d better be blood, bone or barf, or I was going to school,” Stafford said. But “that’s not the case now.”