Why people say 'brakes' when a car has only one brake?
I read an article about a crazed dog savaging an innocent passer-by:
Shocking CCTV footage shows a crazed 'devil dog' pit bull savages a woman in the street.
A van driver then slams on his [brakes] and [run over] armed with a weapon in a desperate bid to stop the attack.
The dog's 19-year-old owner Josh Miller [admitted being] in charge of a dangerously out of control dog in July this year.
A shopkeeper from a nearby shop said, "It was really bad and I've heard she can't really leave the house now because of the [impact it's had on her]."
Q1. A car has a brake on its floor and it's just one, right? And why is it used as plural?
Q2. It's a little confusing. What does 'run over' mean there?
Q3. [admit to ~ing VS admit ~ing] I think 'to' must be added, but is it also grammatically fine without it?
Q4. The last sentence, "...impact it's had on her." Does it sound natural?