[rc5150]

Can you still commit a crime if you don't know that what you're doing is against the law?

[tiedieconderoga]

Not usually, no.

https://en.wikipedia.org/wiki/Mens_rea

You can definitely be convicted of one, though!

[gtvwill]

Lol thought experiment. Your driving in a new area and don't see a change in speed limit because a large truck blocked your view of the sign as you passed it. You get pulled over a short period later for going 20 above the speed limit. Do you think you can be fined or not? Should you be fined or not?

[BenjiWiebe]

You can be fined, the fine might be reversible in court, you shouldn't be fined.

The cop should just give you a warning.