The parking brake in your car is just that - a parking brake. Not a handbrake. Not an e-brake. Not an emergency brake. In fact, in the event of an emergency, the last control in the car that you want to touch is the parking brake. Locking the rear wheels at any speed will result in a spin.
When I moved to the US I was appalled at how many people (read : it seems to be everyone) don't know the most basic things about the parking brake. Like why you use it when you're stopped at an intersection.
I'll tell you why - if someone rear-ends you at an intersection, and you only have your foot on the regular brake, two things will happen. (1) you will jerk your foot off the brake because of the rear impact, which means that (2) you will either run into the car in front, or worse - roll into the intersection into oncoming or crossing traffic.
However - if you have the parking brake on, your foot coming off the brakes makes no difference, and the distance you will be pushed will be considerably reduced, and as an added bonus, you won't roll anywhere.
When I moved to the US and had to sit a driving test, the examiner thought I was bit funny in the head to use the parking brake at every intersection, until I explained the above to him, at which point he said "I'd never heard of that before." And he was not only a driving instructor - he was a tester/examiner! Explains a lot about how people drive around here.
I went on to explain to him why I always waited to turn across traffic with my wheels straight too. It's the same principal. If someone runs into you from behind, and your wheels are turned, you'll be shunted across the road into oncoming traffic. At least if the wheels are straight you'll go more or less straight ahead. Again - total confusion from the examiner.
Here's another tip for automatic gearboxes - the pawl that drops into the notch on the outside of the main clutch housing when you put the car in "Park" is not very strong. Not really strong enough to keep the car stationary on anything other than level ground. Sure - you just throw the car in "park" when on hills and everywhere, but that is slowly eating away the edge of that notch and one day, the parking pawl will slip out and your car will take off with the gear shifter firmly in "P". So here's the tip : use the parking brake every time your park - it reduces the chances of the "P" setting in the gearbox giving up on you one day.
What's worrying about all this was illustrated when we went to a 'new owners' evening at the dealership where we bought our car. It was one of those freebies to explain the nuances of that particular brand, with free drinks and snacks, in the hope that we'd buy accessories or something. Anyway, one driver asked "when should I use the emergency brake?" (aagh - it's not a fucking EMERGENCY brake!) The "expert" from the dealership said - verbatim - "Never - I don't know why they even bother putting them in cars any more."