DS1 (21) had a 50cc moped (not a scooter, a kind of traily-type bike) at 16, rode for a year with no problems. After passing his test on a borrowed 125, he then ran a 250 and is now on a 600. He also has a car.
DS2 (18) is currently using the same bike because his 125 is in need of repairs.
We live rurally, and to access town/village it's a 4 or 5 mile run, mostly on a 60mph A road but with half a mile of narrow, twisty back road. Public transport is a joke, especially at night, and tbh I think the boys were safer on bikes than on buses, with knife-carrying drunks.
I'm actually more worried about the fact the bike is restricted to just over 30mph than the fact it's a two-wheeler, but it'd be safer in town.
"Safety stuff" isn't some kind of optional extra btw - they're not allowed on the roads until they have passed Compulsory Basic Training, and a crash helmet is compulsory. I would further advise good quality gloves, boots and protective clothing, and as much fluorescent/retroreflective gear as you can pile onto a 16 year old.
I'm not going to say it's all been great - spilt diesel is a hazard, as is gravel/piles of wet leaves on corners - and both boys have had not-their-fault accidents but no serious injuries.
On the positive side, they've learned good road sense, they have independence, 50cc bikes use surprisingly little fuel and they both started building up no-claims bonuses for the future - which will make a big difference.
DS2 is taking his car test in a couple of weeks and we'll be buying him a car soon after, because I'd prefer him to be in a tin box when the winter comes in, but tbh I'm really more concerned about the "giving lifts to friends" thing that then arises. He's a sensible lad but I worry about a car-load of rowdy teenagers being a bit of a distraction.
But, he's an adult now, I just have to trust him.