A US woman has pleaded not guilty to what is believed to be the first traffic ticket alleging a motorist was using Google Glass while driving.

The device, not yet widely available to the public, features a thumbnail-size transparent display above the right eye.

Cecilia Abadie was pulled over on suspicion of speeding in October. The officer saw she had Google Glass and tacked on a citation usually given to drivers who may be distracted by a video screen.

On Tuesday, Abadie pleaded not guilty to both charges in San Diego traffic court.

Her lawyer says she will testify at a trial scheduled for January that the glasses were not on when Abadie was driving, but activated when she looked up at the officer.