Pulling over is when you go to the side of the road and stop. Pulling off is going down a side road or driveway. You can’t say “pull over” to refer to continuing to go down a separate road, but you can use “pull off.” You can’t use “pull off” to refer to getting to the side of the road to get out of the way of an emergency vehicle, or to drop off a friend, because you’re on the same road and haven’t pulled off that road. You can use pull over for those situations. When you pull over you have stopped the car. When you pull off you keep going.
Examples:
(Getting off the highway) Pull off here, this is our exit.
(Directions) To get to my house you have to pull off and go down that road.
(Police chase) The driver has pulled off CR 25 and is heading down the frontage road.
(Emergency vehicle) In the United States you must pull over for all emergency vehicles with lights and sirens on.
(Taxi) Pull over here, this is my apartment.
(Car sickness) Pull over quick! I’m gonna be sick!
(Family distracting the driver) If you don’t stop fighting in the back seat kids I swear I will pull over and tan your hides!
