TACOMA - Two people strolling through Point Defiance Park and enjoying the Thursday aftternoon sunshine were critically injured when a speeding driver slammed into them Thursday afternoon.

Tacoma police said the 18-year-old motorist was travelling at about 50 to 70 mph along a narrow, winding park road when he lost control of the vehicle, left the roadway and struck the two pedestrians, a man and a woman, before the car rolled over on its top.

The posted speed limit on that stretch of road is 20 mph.

The woman was taken to Harborview Medical Center in Seattle, where she is listed in critical condition.

The man was transported to St. Joseph Medical Center, where he is in the intensive care unit in critical condition.

The driver, who was not identified, was arrested, then later posted bail.

Police are investigating to see whether alcohol or drugs were a factor in the accident.