Maybe it's just used my Ontario? I noticed the traffic signs in Canada are slightly different than the ones in the states, such as the keep right symbol sign and yield and do not enter signs. Interesting how yield signs and do not enter signs in canada don't have the words on them, but stop signs do.
Heh, you should see the European road sign system! They're COMPLETELY different from ours! Even in Canada almost all road signs are identical to American ones or very resembling.