First, there was eyewear.  Then, there was sunwear.  Now there is Transitions Drivewear, the first lens designed specifically to meet the unique visual demands of the driving task. 
Transitions Drivewear lenses uniquely combine two of the most advanced technologies found in the eyeglass industry today: Transitions® Photochromic Technology and NuPolar® polarization.
Transitions Drivewear lenses are the first photochromic lenses to darken behind the windshield of a car, allowing Drivewear to change color based on current driving conditions in order to enhance the driver’s vision.  In addition, Drivewear lenses are polarized to block blinding glare, another distinct advantage when driving a car.
Labs can retrieve technical specifications here.

Transitions and the swirl are registered trademarks of Transitions Optical, Inc.  
Photochromic performance is influenced by temperature, UV exposure, and lens material.