This question is asked by just about everyone who comes to check out Ariel. I can remember asking it when we were in Ariel on our pilot trip. We were told by Avi Z.(name not changed to protect his innocence), who was the Ariel Aliyah Coordinator at the time, that we do not need a car to live in Ariel (He still stands by it). So the short answer is no, you don’t need a car. There are a lot of people, both olim and Israeli’s, who have been in Ariel for several years and manage just fine without a car.
There are buses and Haso’ot (transportation vans) that run through the city every 15 minutes and continue on to Rosh Ha’ayin, Petach Tikva, and Tel Aviv. There are also buses that go to Jerusalem, so one can rely on public transportation. Lots of people also “tremp” or hitchhike both to Jerusalem and to the Petach Tikvah/Tel Aviv area.
In my humble opinion there are more factors that go into it than that. I think it really depends on the person and their background. I came from Detroit; I had a car since I was 18 years old and never had to use public transportation. The idea of waiting around for the bus was so foreign to me, that when I got here I preferred walking than waiting for the bus. So for someone from New York, who is used to taking buses and subway and a variety of public transportation, it might be an easier adjustment than for someone from the Midwest who is used to driving everywhere. Also it depends on the number of kids you have, bringing one kid on the bus is easy, but taking 3 or 4 young ones can be tough.
Before we bought a car, we would rent one during vacations and holidays. That was convenient for those times that we wanted the freedom to drive around to visit family and friends and participate in the activities going on all around the country In the long run it was cheaper than owning a car at the time, but it could also be a hassle to deal with picking up and returning the car.
I think what finally gave us the push to buy a car was one evening the wife and I went to a movie in Petach Tikva. After the movie, it was getting late and our babysitter had to get home. We waited by the bus stop for about 45 minutes but what felt like hours, knowing that we really needed to get back. Another 45 minutes on the bus and we were home. I remember thinking myself that this is crazy, we live 20-25 minutes from the mall, there is no reason it should take us an hour and half to get home.
As I think of my friends and people I know in Ariel, there are a good percentage of them that don’t have a car, so one definitely doesn’t NEED a car. It comes down to personal preference and financial flexibility.
Of course, there are always exceptions, what if you have a job in a location that isn’t easily accessible by public transportation or you have family/friends that you plan on visiting often who aren’t easily accessible, or a doctor’s appointment that is out of the way. When that is the case then wherever you live you’d probably need a car, and not specific to Ariel.
Ariel Anglos 
I agree, need a car- you don’t need one but it does make life easier. It also really depends on where you work – one of my husband’s jobs is local and his first job had a Hasaa (work sponsored shuttle). But I’ve been working the past three years in Jerusalem and I wouldn’t see my kids if I didn’t have a car! Within Ariel there is really a lot in terms of shopping needs, but if you have lots of family you want to visit a car is nice.
I remember being carless with the wife. We had a good time busing everywhere and the ‘together’ is different between when you scrunched up together on a bus and if you are driving somewhere.
The catalyst for me buying a car 12 years ago, was waiting at Tzomet Yarkon for the x86 and watching bus after bus pass by without stopping. Too packed. Having a car to drive to work was great, but about several months later, I went back to bus, because it cost over 1000sheks for gas a month, plus the frequent visits to the garage $$$ because i was doing about 3000kms a month.
You got it right about the kids. When all you have to do is bring them to one place, nursery and nearby nanny, it’s ok. But when they are split up – nursery and school, it get’s harder until they are old enough to walk alone and take their siblings.