Erm, I've found this all quite difficult to deal with. I think people's experiences vary. I grew up in Birmingham:
At 14 - Grabbed by a man while coming home from the chip shop. Summer's evening. Still light. I chopped down on his wrist (as my Dad had shown me) and let off a foul mouthed tirade. He ran away.
At 15 - Cornered on the top deck of a bus on my way home from school at about 4pm. The man sat next to me, taking the aisle seat, and then masturbated. I couldn't get out and I just froze. He finished and got off the bus.
At 18 - Driving a car, trying to pull out of a tight parking space, rolled down the window to I could stick my head out, looked over my shoulder briefly, when I returned to eyes front there was a man with his penis in his hand close to my face. I recoiled. He shoved it through the car window. I was struggling to get the window up quickly. My niece, who was about eight at the time, was in the back. Broad daylight.
At 20 - Cycling home from work (in a pub, so it was about 11.45pm). Main road. Got jumped by three guys, all of whom seemed to be drunk. Fell off my bike. They began to drag me / pull at my clothes, but I had a chain and padlock over my shoulder (bike lock) and I started swinging that. Caught one of them quite badly. He literally didn't know what had hit him. They ran away.
At 21 - Jumped by a guy as I was walking down the landing to my flat. I was six months pregnant and he pulled a knife on me. I ran. Just about managed to get the door open, and behind that door was my dog, Buster (Buzzy for short), a rottweiler x alsatian who was trained to protect (see above for why I might think I needed this). The guy saw the dog and turned tail, but the dog gave chase, caught him and pinned him against the wall. I'm not proposing this as a method of self-defence, however, I was living in a very rough area at the time ...
After I had the baby, I just didn't go out at night, had two more babies, didn't go out at night on my own for years. Moved to a nicer area. Even then, though, the last time I got hassled in the street was relatively recently, a man following me home after I'd been to the pub. I turned round and told him to get lost. He didn't. Luckily, I was near a 24/7 shop and so I walked in there and told the security guard what was happening, he chased the guy away and I phoned my husband to come and get me.
In short, I think it depends where you live, how 'on top' the street culture is there, and how often you go out (sans car).