Scan Intersections Before Driving Through

Scan Intersections – When the light goes green

Scanning intersections basically means that a driver does an intentional scan of the entire intersection before driving through it, from left to right, whether you have a green light or a green arrow. They actively look as far as they can to the left, center, right, and then left again before continuing to drive.

The most dangerous time at an intersection is often right when the lights are changing; to yellow, red, and then green. This is the most likely time that a driver will be doing something they shouldn’t, such as speeding up instead of slowing down when the light goes yellow. Read more about yellow lights on our blog.

This left-to-right scan is literally a life-saving skill that drivers can do to make sure it is safe to enter an intersection. Just because the light goes green, doesn’t mean it is safe to go through it; in fact, quite the opposite can be true on a regular basis.

Especially important if you are the first driver

Scanning intersections is especially important when you’re the first vehicle at the intersection. If there’s going to be a collision at an intersection, it’s most likely to happen right around the time the lights are changing colors. Do this scan immediately after the light has changed. Make sure your foot is still on the brake pedal, just in case it’s not safe to go.

Scan Intersections Left, Centre, Right & Left Again

Look as far to the left as you can, check the center, then right, and left again. This is to make sure it is safe. Just because the light is green, doesn’t mean anything. There could be vehicles or pedestrians running through the intersection when they shouldn’t.

Checking center (straight ahead)

The reason we also check the center area is that sometimes the oncoming traffic may do something unusual; such as turn left immediately when the light goes green when they shouldn’t be taking the right-of-way, and it’s good to observe this. I’ve seen this happen from time to time over all the years I have been driving.

Sometimes after my left-turn arrow went green and I was about to turn left, an oncoming car would be starting to drive straight through the intersection into my path. So it is good to keep an eye on that area to make sure they are under control.

Even though drivers aren’t supposed to be driving while they are stressed or tired in a perfect world, in the real world, it happens. If that happens, you may need to do whatever you need to in order to prevent a collision. This may be stopping, honking, or somehow getting out of the way. Stopping is not the only way to prevent collisions; in certain scenarios, speeding up to get out of the way will work better.

Scan Intersections – Why check left again?

We always check the left side again because this is the side closest to us. It’s the most dangerous to us in our position in the driver’s seat. If a car runs into the driver’s side of your car and you’re the driver, it might hurt more than a car running into the passenger side of your car when you don’t have a passenger, if you know what I mean.

Red lights don’t stop cars

Don’t assume that a red light can stop a car. A car will stop at a red light usually. But only if the driver sees it and decides to stop. There are many reasons why a driver may go through a red light. Some examples are a medical emergency, being distracted, impaired, or even asleep. And yes, I’ll admit that some people think that yellow means “speed up” and there are other people who simply “don’t feel like” stopping when they should, or they think they are in a hurry and they must do something dangerous.

Green does not necessarily mean “go”

A green light does not always mean go. Green means “go only if it is safe.” It’s up to you to look before you proceed. If there are other cars already in the intersection, you are legally required to yield to them, even when the light is green. This is due to a basic right-of-way rule that states we must yield to any road user who is in any space before us.

Scan Intersections: Why do we look left first?

The car on your left would run into you first if it were to go through an intersection against a red light (or against any traffic control signal).

Scan Intersections
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Say you’re in the white car and your light has just gone green. If these two vehicles went through the red light, the one on the left is closer to you. It would potentially run into you on the driver’s side.

Of course, if there were no vehicle running through the red light on your left, then by all means the one on the right would run into you first.

Scan Intersections always for safe driving habits

Simply make it a habit to scan left, center, right, and then left again before proceeding when your light goes green. This is the crucial type of habit that could save your life one day.

And although we are talking about scanning at green lights, it’s not just this moment that we need to do it. We need to scan 4-way stops, 2-way stops, and many other intersections.

Preparing for your ICBC road test? Be sure to check out my epic article: ICBC Road Test Tips For Classes 5 & 7 [Instructor Gets Deep].

The bottom line

Scanning intersections before going through them is a basic skill for any driver to learn. And, it’s quite easy to do. Simply doing this every time before you go through an intersection will keep you out of trouble. To learn more about preventing collisions and staying out of trouble, check out our defensive driving guide.


Carmen Cohoe

Carmen became a driving instructor in beautiful North Vancouver at the age of 22 due to some crazy people who agreed to hire her. After that, there was never a dull moment teaching many different folks from many different places how to drive using automatic and standard vehicles and a minivan.

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