[smolder]

Yes. They can still drive fine, but don't get the benefits of color coding, like being able to infer whether red or green is lit from the light reflected off of other objects. That becomes somewhat important in low visibility situations where the position is hard to determine.

[teruakohatu]

It seems the harder difficulty is red and yellow, see the comments in this article, but led lights have improved the situation for some:

https://www.color-blindness.com/2007/02/06/colorblind-at-the...

[NegativeK]

There are a few different types of colorblindness, so I wouldn't extrapolate that.

For me personally, the green light looks much closer to a white than to, say, the green of a grass.

[smolder]

I just happen to have a friend with red-green blindness, who was my reference point in answering. It's good to point out there are different types with different impacts, though.