An Exeter woman was seriously injured Tuesday after police said she was struck by a teenage driver while she was walking on a Portsmouth Avenue sidewalk.

The crash happened shortly after 3 p.m. in front of the Gary Blake car dealership. The woman was transported to Exeter Hospital, which is less than a half-mile away.

The woman's name was not released. The driver was identified as a 16-year-old male from Plaistow. His name was also not released. He was driving a Hyundai sedan.

Police Capt. Bill Shupe said the teen's vehicle was traveling north on Portsmouth Avenue toward Stratham when it suddenly veered to the left and struck the woman on the opposite side of the street.

Shupe said it was initially unclear why the teen swerved.

Emergency responders had requested a helicopter to fly the woman to a larger hospital because of the severity of her injuries, but the helicopter couldn't take off because of foggy weather.