My primary school was around the corner from our house, but it wasn't until Year 5 (age 10) that I was allowed to go to school alone. Wasn't until Year 6 that I went home alone too, but then my dad did collect my younger brother in the afternoon so there wasn't really any difference.
High school was 1.2 miles away but during the first two years I only went home by myself twice. I was always taken to/from school by car. Crime and safety was the reason my parents gave. Even though we live in a good area, I was bullied in school at that time. It was Year 9 when I had a three week period of using the bus, as my mum was away, and as I handled that well my parents became slightly more lax in always ensuring they were free around school times, remaining that way until I left in Year 13. I preferred going by car if at the beginning or end of the day but at other times during Year 11 study leave and sixth form I used the bus.
It was by Year 9 I really stopped getting bullied, but I never really had any close friends which meant I was never allowed out to socialise outside school times. Having said that, at the age of 14 I was allowed out to socialise with others living on the estate (a very nice Housing Association owned one

), but it was no substitute for going out somewhere with friends

.
I was allowed to go on the bus to somewhere local. But just going out and about on public transport I had to wait for until I was 16, and neither were easy to be allowed to get permission for at first.
But yes, my parents being overprotective and making me feel uncomfortable in being able to open up to them when I was younger resulted in me losing trust.