A Novato woman was in critical condition Monday at Santa Rosa Memorial Hospital following a motorcycle collision Sunday that killed her husband.

Martha Kolb, 51, was a passenger on the back of her husband's 2008 Harley Davidson traveling on Valley Ford Road east of Carmody Road at 3:20 p.m. when the couple collided with a car driven by Cynthia Callahan, 77, of Petaluma. Callahan was pulling out of her driveway when the collision occurred.

Michael Kolb, 48, died at the scene.

Callahan complained of pain on scene but was not treated, according to CHP.

Alcohol is not considered a factor in the collision.