Scores of high school students went to the prom Saturday night and then roamed the Vineyard looking for a party, and in the course of that night, at least seven figured out they were in some kind of trouble and needed a ride home.

Rather than risk getting behind the wheel and staying in a dangerous situation, they made a smart choice to call for help. From Aquinnah, Chilmark and Katama, they called the hotline for SafeRides of Martha's Vineyard.

High school senior Michelle Leon picked them up and drove them home to all corners of the Island, logging more than 100 miles on her 1993 Honda Accord. By the time she and her co-pilot, Kayla Leonard, parked the car back in Edgartown, it was 3 a.m.

Now, imagine there were no SafeRides, no command center at Columbia TV in the Edgartown Triangle, no place for these teenagers to call.

That's the grim prospect facing SafeRides. A funding shortfall of $6,250 could mean closing down the grassroots, student-operated organization which, in its four years of existence, has shuttled more than 420 young people home, racked up well over 4,000 miles and quite possibly saved many lives along the way.

"Additional funds are critical to the survival of this valuable service," SafeRides co-presidents Lauren Carelli and Elise Chapdelaine wrote this week in a letter to the editor.

What put SafeRides in such a financial fix? Their annual budget of $55,000 pays for the telephone hotline, two-way cell phone radios, medical supplies, training, insurance and administration costs. A state grant of $35,000 came through last October, but part of the deal was that SafeRides would match the remaining $20,000 either in outright cash or through in-kind donations. Now the shortfall of just over $6,000 puts the whole grant in jeopardy.

In many ways, SafeRides has always run on a shoestring, scrambling not only for money but also for parent volunteers willing to stay up all night with the teens waiting for the phone to ring.

The biggest problem, though, has been recruiting drivers. A statewide curfew that keeps drivers under 18 off the road between midnight and 5 a.m. has hamstrung the project from the beginning. The roster of 18-year-olds in the senior class is thin, especially in the first half of the academic year. Even with an ample supply of legal drivers, it's not easy convincing seniors to give up a Saturday night, much less a night at the prom.

But rather than just complain about the problem, the Vineyard teenagers who lead SafeRides have gone to the state legislature and pushed for a new law that would exempt SafeRides drivers from the curfew. If 17-year-olds could drive during the early morning hours when SafeRides receives the majority of its calls for help, then they could get started earlier in the year.

If the law were passed, it would pave the way for other chapters to form across the state. So far, the Vineyard has the only SafeRides affiliate in Massachusetts. The program is part of a nationwide project sponsored by the Boy Scouts of America.

Despite the challenges of finding drivers, parents and cash, SafeRides of Martha's Vineyard has shown no sign of weakening its commitment. In fact, the 14 students who sit on the SafeRides board and meet nearly every Sunday at Pam Carelli's house in Tisbury took on even more work this year.

In March, four members traveled to a regional youth conference in Hyannis to tell other teenagers about their work. That same month, four others flew to Seattle for a three-day national conference on what's called service learning, the idea that teenagers learn something meaningful when they do service for others.

When they weren't explaining to other people what they do here, they looked off-Island for models of how to expand their mission. Case in point: Last March, they invited the leaders of a successful youth program in Great Barrington to come down to the Vineyard and talk about how they managed to steer teenagers in that Berkshire town away from drugs and alcohol and onto dance, theatre and musical stages.

Still, while SafeRides leaders want to widen their work to include any project that would serve the youth of the Island, the core mission of SafeRides is still the free and anonymous service it offers on weekend nights through the school year.

Since they started up this academic year in November, SafeRides drivers have given rides to 125 teenagers. Of that number, 90 called after midnight for a ride. Last Saturday - prom night - Miss Leon was so busy that some teenagers had to wait more than two hours to be picked up. "It's a big problem when people have to wait that long," said Miss Leon.

But without more cell phones and more drivers, there's not much SafeRides can do. "We could be giving rides to a lot more kids," said Pam Carelli, the founder and administrator of SafeRides.

Indeed, the detailed statistics recorded by drivers and tabulated on a computer spreadsheet show there have been other busy nights. Back on March 15, the driver was dispatched for seven calls and ended up giving rides to a total of 17 teens.

SafeRides leaders like Miss Leon want their peers to call. They want the service to thrive. But they know fellow teens are sometimes reluctant to take that step.

"They're a little nervous, but at the same time, they're confident enough to call," said Miss Leon. Clearly, the worst thing SafeRides could do is abandon its post when Island teenagers have grown accustomed to reaching someone when they call 508-939-9100.

"It was kind of difficult giving up my prom night," said Miss Leon. "But I'm a board member and a driver. With me running that night, it made it possible. I felt it was worth it."