What do green lights on cars actually mean?

A predictable merge.

A motorist who notices the signal.

Another driver who avoids blocking an intersection.

None of these actions requires panic or speculation.

They require awareness.

That is ultimately what the green light is trying to create.

The Best Response Is Awareness, Not Guesswork

If you encounter a flashing green light, first recognize that its legal meaning depends on the location.

If you are in Ontario, official guidance explains that some firefighters and volunteer medical responders may use flashing green lights while responding in their own vehicles.

Motorists are encouraged to yield the right-of-way so they can respond quickly and safely.

That does not mean abandoning normal caution.

Look around.

Stay predictable.

Create space when it is safe.

And avoid inventing details about the emergency that the light cannot possibly reveal.

There may be a fire.

There may be a medical call.

There may be another qualifying emergency.

The driver beside you does not need to know which one.

The important information is already visible.

Someone authorized to use that signal may be trying to get where they are needed.

And sometimes the most useful thing another motorist can do is surprisingly simple: notice the light, understand its purpose, and safely make room.