Scanning and blind spots — Pennsylvania Permit Test
Scanning and blind spots on the Pennsylvania permit test — 9 rules, each with the reason behind it and a question on it while it is fresh.
The rules
You should be able to identify problems 12 to 15 seconds ahead, which is about one block in the city or a quarter mile at highway speed.
Looking that far ahead turns a sudden problem into one you saw coming.
At an intersection follow the left-right-left rule: look left first because vehicles from the left are closer to you, then right, then left again before you pull out.
The near lane is the one that reaches you first, and it comes from your left.
A blind spot is any place around a vehicle a driver cannot see without moving their head.
No mirror covers it, which is why the only fix is to turn your head.
Before changing lanes, signal, check your mirrors, and look over your left and right shoulders; do not depend on mirrors or sensors alone.
Mirrors and sensors both leave out the piece of road right beside your back wheel.
On roads with three or more lanes, check every lane before you change lanes, because somebody in another lane may be planning to move into the same space.
Two drivers can pick the same empty lane at the same moment.
Avoid driving on either side and slightly to the rear of another vehicle for long, because both positions are blind spots: speed up or drop back instead.
Sitting there means the other driver has no idea you exist.
Set the inside mirror so you can see the traffic directly behind you, and the side mirrors so that when you lean left or right you can only just see the side of your own vehicle.
Mirrors set to show your own car twice are showing you the same thing twice.
When backing up, check behind the vehicle before you get in, then turn your head so you can see through the rear window; children and small objects are hard to see from the driver's seat.
Walking round the car once is the only way to see what is too low for any mirror.
It is against the law to hang anything from the rearview mirror while the vehicle is moving, or to place anything on the windshield that blocks the driver's view.
Anything dangling there sits exactly where a person on foot would appear.
On the test
How far ahead should you look to spot problems early?
12 to 15 seconds ahead. Looking that far ahead turns a sudden problem into one you saw coming.
How this works
Most practice tests hand you a bank of questions and leave the manual somewhere else. This one puts them together.
You read one law and the reason behind it, then answer a question on that law while it is still fresh. Get it right and you move on; get it wrong and you have found the gap while it is cheap to fix, not on the morning of the exam.
Learning one rule at a time, and proving it immediately, is what turns a manual you skimmed into something you actually know — and it makes studying feel like getting somewhere rather than like waiting to find out.
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Where these come from
Every rule here is checked against PA Driver's Manual, published by the Pennsylvania Department of Transportation, and against the state code itself. Last checked 2026-09-06.