The best solution I've found for my purposes are "Fitovers" sunglasses. "Fitovers" is the brand name, and as it implies, their sunglasses are designed to fit over regular prescription glasses.
(Link Removed - No Longer Exists)
Another brand I like offering a similar product is Cocoons.
The reasons I like them are:
1. Inexpensive compared to prescription sunglasses, yet very high quality.
2. Polarized lenses for excellent glare protection.
3. Different color lenses are available (amber lenses are very nice to use when driving or riding in white-out conditions).
4. The lenses are over-sized so the frames wrap around the top and sides of my glasses, providing extra glare and wind protection.
5. They work in car, unlike Transitions.
You'll have to pay attention to sizing when ordering these glasses. Some of the cooler styles won't fit over larger glass frames. There are very good sizing instructions on the product websites:
https://fitovers.com/
https://cocoonseyewear.com/
I have found the sizing instructions to be a little conservative, so if you are close to a smaller size, you might well be able to use it.