Any adults here learn how to ride a bike?

I think I had to re-learn as an adult. Up until 6 or 7 years ago, I hadn't been on a bike since grade school. I now do several Century rides a year. I would recommend a Hybrid type bike to start with.

Edited to say that I am 45 years old.

When we were teaching our daughter to ride a bike the guy at the local bike shop suggested removing the pedals and letting her learn to balance first. She used her feet to get the bike going and could balance with her feet near the ground to catch her if she got off balance. It worked really well. Once she was comfortable, we put the pedals back on and she learnedmto pedal pretty quickly.
I can see something like that working for an adult in your environment.

I teach people to ride bikes. My oldest to date was 72 and wanted to ride with her grandchildren. Take the peddles off lower the saddle a bit and use it as a strider bike until you learn balance, then put the peddles back on and off you go.

I had to re-learn how to ride a bike when I got promoted to my current position as roving security at the school district that I work at. I hadn't ridden a bike since I was 6 years old (got the promotion when I was 32) and it proved to be a real....... pain in the butt to learn all over again. The person that said "it's just like riding a bike" was obviously more talented than me. I had a short time to learn being that I was to be road tested in a few weeks so I took my share of bumps and bruises jumping curbs, going down stairs, riding through gravel and so on. I have fairly good balance but that only counts for so much when you are navigating through tough terrain, you really have to have a feel for the bike at that point. This is not to discourage you by any means but more to say that it will be a work in progress so don't be upset if you don't get it right off the bat.
As far as being in an urban area, you just have to start paying attention to where bike paths are around your city. I know that once I re-learned to ride I started noticing where there were hidden bike paths all over. Also notice what streets have a true bike lane but my advice would be to stick to residential streets until you become more comfortable with riding next to vehicles. Try the link below to map out bike routed in your area. There are other sites as well if you just Google it.
Good Luck!

http://www.mapmyride.com/routes/

I would say it maybe easier to learn how to ride a bike as an adult. You have stronger muscles, probably better balance, hopefully common sense for what you can do and what you can't do. The only possible negative maybe more body mass. The hardest part will be the takeoff, then learning turning radius and leaning into the turn, braking, and getting to know your bike.
I hadn't ridden a bike since I was 16 and got a car. Then in my early 50's I started riding again for exercise and I haven't wrecked yet! Knock on wood!

I learned as a child and have taught several children. I am sure this will work for you too. My method is to find a small grassy hill (small is fine) and start at the top. My son learned on a small grade hill with about 10 yards of distance available.

1-Ride the bike down the hill, letting gravity provide the power. Concentrate on maintaining balance. Now walk your bike back up and repeat.
2-As you get that down pat, take a Frisbee and throw it to the bottom of the hill. Now ride down the hill and run over it with your bike in order to learn how to steer.
3-As you get better, throw the Frisbee out further to incorporate pedaling while steering

I have never seen this take more than a couple of hours to get down pat (with children that is...fast learners!)

Good Luck,
Curt