Others have complained that they don't change behind a windshield. I wore glass lenses for a lot of years because, for the longest time, photochromatic lenses were not available in plastic. Even when they became available, I was reluctant to change to plastic because the state of the art at that time was such that plastic lenses didn't change as much as glass. They still don't, but they change much more than the earlier plastic lenses.
I have prescription polaroids that I wear while driving and when I'm on the water. My optometrist recommended them some years ago when she learned we spend a lot of time on the water. I'm glad I took her advice.