Flashcards are widely used as a learning drill to aid memorization by way of spaced repetition.
They burn visual information into the brain as they engage active recall. Brain is given a clue on the front side and they attempt to actively recall the answer on the back. It means that learners are forcing their brain to remember a concept. This makes using flashcards such a compelling method of memorization.
It is great way to learn and quickly memorize traffic signs.
This is free Lite version with 10 signs in each category. If you like it, you can buy full version.