They don't know exactly when, but the time is coming.

Any day now, student drivers at the high schools in York County could be checked for the second round of the York County High School Seat Belt Challenge.

The competition's goal: to ensure teen drivers are abiding by changes recently made to Pennsylvania law requiring every vehicle passenger between the ages of 8 and 18 wear seat belts. Drivers 18 and under must also wear seat belts.

And since seat belt violations are now a primary offense, police may pull over a young driver for non-compliance even if another traffic infraction hasn't been committed.

The Center for Traffic Safety is holding the competition, which was held in Lancaster County from 1999 to 2006 and brought back last year.

"The competition was very successful in Lancaster County, and we decided to duplicate it in York because of its success in Lancaster, but also because we have a new seat belt law that recently went into effect," said Laura Fagan, traffic safety specialist with the Center for Traffic Safety.

How it works: So the week of March 5, the center conducted an unannounced check of the percentage of students wearing seat belts as they arrived at or left from school. The unannounced observational survey was conducted at every high school in York County.

Results were sent to every high school in York County with an invitation to participate in the competition. South Western, Dallastown, Dover, Kennard-Dale, Northeastern, Spring Grove, Susquehannock,

York Catholic and York County School of Technology chose to participate. The initial survey results from those nine schools ranged from 66 percent to 88 percent usage rates.

The next observation will be conducted on unannounced dates in late April.

Gearing up: "We had an 84 percent baseline initially, but until we get 100 percent, we won't be satisfied," said South Western Principal Walter Graves.

South Western has promoted the competition with reminders on its Mustang Vision news broadcast, and also through posters around campus and information shared in driver education classes.

"Seat belt safety is important for anybody, especially our student drivers," said Graves. "The main point is that they need to wear seat belts. We want to have them around for many more years."

Participating schools also have the added incentive of receiving a $500 mini-grant from State Farm Insurance if they have the highest usage rate.

State Farm also will award a $500 mini-grant to the school with the highest increase in usage rates from the time of the first survey to the next unannounced observation.

The mini-grants will be used for promoting traffic safety, and the winners will be announced in May.

Motor vehicle crashes are the number one cause of death for teenagers, said Fagan, so ultimately the goal of the campaign is to increase seat belt usage rates so the number of motor vehicle fatalities will decrease.