I had single vision sunglasses for a while, but found I was constantly removing them or looking above them in order to read or see things close up. I was surprised at how often I look at things close up even when outdoors doing outdoor things like riding my scooter. My last pair I got progressive sunglasses and they are great. I can’t see being without the reading ability now.
I use mine for cycling a lot, so I did not want a hard line bifocal, or even my own standard progressive; I gave up some near focus reading ability for a smoother transition of my peripheral vision.
My glasses turn dark with sunlight no need of sun glasses.
I run Progressives in both. I wear my sunglasses in amusement parks, fishing, and a lot of other places where single vision wouldn’t be a good thing for me. Its just easier than carrying both pairs and switching all the time.
Former optician (15 years) here. If you regret not getting progressives, it will likely be because you won’t be able to see the dashboard clearly. Depending on your age, you may be fine. You should be able to get a good idea how it would work by sitting up in your car seat and dropping your head so you force yourself to look at the dash through the distance part of your lenses. (Don’t do this while actually driving.)
The distortion drive me bonkers. I had headaches and felt weird for a couple of weeks, and was finally able to wear the things, but I found it very disorienting that everything moved around when I moved my head.
I used to use single vision for driving at night so I didn’t have move my head so much to read signs and stuff
Then I got digital progressive lenses. They are expensive, but they work fabulously. The sweet spot is bigger, and there’s much less distortion.
(I only wear sunglasses after getting my eyes dilated for an exam, and I’d probably pick a dorky option if I did.)
The last time I got new glasses, I got frames with magnetically attached sunglasses. They are great. Very easy to put on and take off in the car. I just leave the clip on in the car in the little compartment in the dash under my radio. They are so much easier than clip ons, and my eye doctor assured me they can be easily replaced if they are lost or broken.
Except while driving. Most transition lenses turn dark with UV exposure, so they don’t turn dark when you are in the car.
I believe there is one type that works differently, so maybe you have those, and are able to use them while driving. I do not. 
I’ve had the transitions in the past and didn’t like them. They have a tiny bit of tint even indoors that I don’t like, and don’t get dark enough. There’s another level that does get dark enough outside, but has an even darker indoor/always there tint that’s a nonstarter for me.
I have yet to find a clip-on style that looks really good, they don’t sit perfectly flush with the Rx portion of the lenses and I don’t like how that looks. So, separate Rx sunglasses for me. My everyday non-shaded glasses are relatively small and rimless. Those don’t translate well to sunshade anyway, as for sunglasses I prefer a larger frame with more coverage.
I have a credit with Zenni right now, plus a Visa gift card, that will make my out-of-pocket pretty small for a pair of black frames with mirrored Rx lenses. I can definitely see the dash fine with the “far” portion of my current progressives, so I think the bi-focal option will work fine. I wouldn’t have thought of that if I hadn’t started this thread!
Hmm. After all that, I did a comparison in price with the frames I want and the difference in price between the progressives and bi-focals is a whole 9 bucks. So. Went with progressives after all. The lenses are only 1mm wider than the ones I use daily, so they won’t be noticeably thicker or heavier. (Big astigmatism in left eye, makes for thick lenses if I don’t get the upgraded ones.)
Black frames with clear accenting and mirrored lenses. I end up walking (not so much driving) into the sunset often, and it will be a relief to have shades again.
Update: Here they are! I’m very happy, they fit right out of the case. I can’t believe I didn’t even need to adjust the temples, I always have to adjust those! Glad I went ahead with what I’m now used to for lenses, and a classic frame that should last a few years. https://scontent-ord1-1.xx.fbcdn.net/hphotos-xpa1/v/t1.0-9/11204456_883395698362785_8456300649686960088_n.jpg?oh=953e2cd4e684a891399a79dda5d239f9&oe=56A55666 (it’s a public facebook pic, everyone should be able to see it. I think.)
I just wear a pair of these over my progressives while I’m driving.
All the girls crazy 'bout a sharp-dressed man…