The National Park Service will conduct an internal review of safety regulations at Haleakala National Park after three French tourists died when their car drove off a wilderness road without guardrails and landed at the bottom of a gulch.

The driver and lone survivor of the crash, Dr. Bernard Ortolan, 60, of Sceaux, France, remains in critical condition at Maui Memorial Medical Center. Ortolan was wearing his seat belt, according to the park service.

Interviews conducted by park investigators indicate that Ortolan most likely fell asleep at the wheel and veered off a section of Crater Road, according to a news release. Speed also appears to be a factor, based on the amount of damage suffered by the vehicle, the park service said.

Ortolan's wife, Anne Verger, 58, was declared dead at the scene.

The second victim, 65-year-old Rolande Andina of Paris, was traveling with the couple's tour group, as was the third victim, 49-year-old Philippe Chaigneau, also of Paris. The name of the tour group was not released.

Chaigneau is survived by his wife and two teenage children, who were traveling in a separate vehicle.

An internal investigation reviewing the park's safety and speed guidelines will be conducted, but park supervisors do not foresee installing guardrails along the park's winding roads, some of which were built in the 1930s.

"This is a tragedy, but there is no intention to put in any guardrails. It's a historic road and it is very typical of roads in natural parks designed as scenic roads that have low speeds," said Sharon Ringsven, a ranger at Haleakala National Park. "For myself and another ranger, who has been here 20-plus years, this is the first motor vehicle fatality in the park in more than 20 years."

The accident occurred on a stretch of roadway that runs beside a steep drop-off. There are three plastic reflector poles marking the gulch, but no guardrails. In a previous interview, Ringsven said a similar accident at the same spot occurred three or four years ago, but no one was injured.

Mary Evanson, a member of the nonprofit corporation Friends of Haleakala National Park, said she mourns the loss of life but hopes the natural beauty of the park is not tainted by guardrails.

"This will bring up the discussion of whether or not there is a need for guardrails," said Evanson. "It's tragic, but I hope they don't install guardrails. It's a wilderness and a beautiful place and we need places like that. If people go slow and keep their eyes on the road, they are going to be OK."

Patricia Lee, France's honorary consul in Hawai'i, called the accident a terrible tragedy, and said she spoke with Ortolan by phone yesterday.

"It's very difficult; it's just a real tragedy for French citizens," Lee said.

Ortolan is in touch with his family in France, although his children are traveling and could not be reached, she said. He is in critical condition and is unable to travel, Lee said.

Ortolan is a private physician with "ministerial duties" at the French Ministry of Health.

"We're doing everything we can and coordinating with the consul general in San Francisco," she said. "We are in touch with their families."

The accident occurred sometime after 1 p.m. Thursday at milepost 13.2 on Crater Road at about 7,600 feet, two miles up from the park headquarters.

The car was headed down from the park summit when Ortolan apparently fell asleep at the wheel and veered off the road, according to the park service.

Park ranger and crash investigator Michael Ing said the vehicle left the roadway and went airborne for about 40 feet. It slammed into the rocks on the opposite side of the gulch, then rolled back down about 15 feet before landing in the bottom of the gulch, according to the park service.

Damage to the car and the distance it traveled in the air after leaving the roadway suggest speed was a factor, according to investigators.

There were no witnesses to the accident.

The survivor and victims were traveling with seven others as part of a tour group that had hiked down Sliding Sands trail and had returned to the parking lot at about 12:30 p.m.

The group members left the trailhead in different cars at different times. The other members noticed the four missing tourists at about 2:30 and notified park rangers after searching at overlooks and parking areas.

A park ranger who received the report had just come down from the summit and did not see the car anywhere along the road, according to the park service.

At 3:45 p.m., a bicyclist in the park saw the vehicle down in the gulch and waved down other visitors to call 911. The park service received the report of the accident at 4:10 p.m.

The national park was the third-most popular tourist attraction in the state last year, with 1.43 million visitors. The 29,110-acre park was the nation's 50th most popular spot in 2006.

Officials have announced plans for a major renovation of park headquarters at the 7,000-foot elevation and for improvements to the two small visitor centers at the 10,000-foot peak.

Reach Peter Boylan at pboylan@honoluluadvertiser.com.