Edgartown police responded to two major accidents this past week: one involving a pair of Harley-Davidson motorcycles and another involving a pair of bicycles. In both cases, one person involved in the accident was seriously injured and airlifted by helicopter to Boston-based hospitals.

Edgartown Lieut. Tony Bettencourt said police received a call of a motorcycle accident on the West Tisbury-Edgartown Road around 1 p.m. on Friday. Two motorcycles were reportedly heading out of town and driving side by side when one of the operators lost control and crashed into the woods along the side of the road.

Richard Carlson, 56, of Kingston, sustained serious injuries in the crash. As of Friday afternoon Mr. Carlson was listed in critical condition at the Boston Medical Center; an attempt to check on his condition yesterday was unsuccessful.

Lieut. Bettencourt said police received different eyewitness accounts of what happened. One eyewitness said Mr. Carlson may have collided with another motorcycle; another said there was no collision. The investigation into the accident is ongoing.

Just before 5 p.m. on Friday, Edgartown police responded to an accident involving two bicycles near the corner of South Water street and Davis Lane. When police arrived they found a woman, later identified as Deborah Sherman of Framingham, lying unconscious on the ground.

Ms. Sherman, 60, was transported by ambulance to Martha’s Vineyard Hospital and was later airlifted by helicopter to a Boston-area hospital.

Lieutenant Bettencourt said Ms. Sherman was pedaling up Davis Lane when she came across another bicyclist, David Barton, 20, of Baltimore, Md., who was traveling in the wrong direction along the one-way street. The two cyclists tried unsuccessfully to maneuver around one another.

They collided head-on and Ms. Sherman was thrown onto the pavement.

Mr. Barton told police he was lost. No citations have been issued; the investigation is ongoing.

Just after midnight on Monday morning, Edgartown police arrested a man for driving drunk after he reportedly crashed his 1994 Chevy van into a telephone pole on the Edgartown-West Tisbury Road. Officer Geoffrey Phillips reportedly found Richard Olenick, 44, of Tisbury sitting in the driver’s side of the crashed vehicle.

After undergoing a field sobriety test, Mr. Olenick was charged with operating under the influence of alcohol, negligent operation and marked lanes violation. He was brought to Martha’s Vineyard Hospital to be treated for injuries, and his vehicle was towed from the scene.