PACIFIC CITY, Ore. (AP) _ Police still don't know what led to a fatal crash of two sand rails at Sand Lake Recreation Area, but the deputy who patrols the popular dunes says it was only a matter of time.

"There are a number of these overpowered vehicles," said Tillamook Sheriff's Deputy Jim Horton. "They are capable of very high speeds, and most are capable of pulling the front wheels off the ground and keeping them that way as they tear off across the flats."

Sand rails are made of fabricated metal tubing and designed for hill climbing and speed. Typically, they have roll bars and harnesses.

David Leach, 56, of Hillsboro and Chiara Acker, 19, of Aloha died Sept. 26 when a sand rail driven by David Rieman, 47, of Clark County collided with Leach's.

Rieman was released from the hospital Thursday. Leach had two passengers. Phillip R. Snider, 25, and Savina Rosales, 19, of Aloha, both were listed in good condition.

Rieman's sand rail was powered by a Cadillac NorthStar V-8 engine, Horton said. "It's the kind you find in a passenger car. The sand rail is going to weigh much less than a passenger vehicle. Just by that alone, it is going to be very powerful," he said.

The speed limit on the dunes is 55 mph, but it's difficult to enforce, Horton said.

Three people have died at Sand Lake in the past 10 months. Last November, a man died after his four-wheeler collided with another.

Accidents on the dunes are common everywhere, but Sand Lake is small — 900 acres, compared with the Oregon Dunes National Recreation Area's 32,500 acres. And it is popular.

"We've had so many people that usually go to Florence, but they don't want go the extra distance because of the gas prices," said Nancy Swanson, one of three camp hosts at Sand Lake.

From April to September, people start arriving on Thursdays, hauling trailers crammed with four-wheelers, dirt bikes, dune buggies and sand rails.

By noon, the campsites are generally spoken for, and it stays that way through Sunday.

Swanson said new riders often stop to ask about the rules, but not everyone shows such common sense.

"You should have seen the guy on the four-wheeler with the 2-month-old in his backpack," she said, shaking her head.

After last week's sand rail crash, a wooden cross with a Sharpie attached for leaving notes marked the spot where the vehicles hit head on. The crash will give some riders pause, said Horton.

But a day after the fatal accident, Horton was called to a rollover on the beach, where the speed limit is 25 mph. By the time he arrived, the vehicle had been righted, and its three occupants stood nearby. All had been drinking and one admitted he'd been driving with a beer in his lap as he tried to whip doughnuts on the crowded beach.

Alcohol has been banned in the riding area for about five years, yet it remains one of the biggest contributing factors to the accidents. Speed, aggressive driving and driving beyond a person's ability contribute to the accidents, as well.

In July, Tillamook County commissioners set a midnight curfew starting Sept. 1 for riding on the sand. Rigs are not permitted back on the beach until after 6 a.m.