I'm going to date myself here, but I remember in a '56 driver's ed. class the teacher explaining how to stop a car/truck in an emergency, with the emergency brake! He said don't be timid, pull it out sharply,(if you had that kind of brake) or step on it firmly. The ideal was to bring the vehicle to a stop asap. I've never tried it but I suppose you could lock up the rear wheels if you applied them hard enough but if you've ever used mechanical brakes you know that would take a LOT of pressure.
