http://www.knifeup.com/state-knife-c...w-your-rights/


http://www.knifeup.com/colorado-knife-law/

The first one is a quick and easy reference, the second one applies to colorado. From the way I read it, a push dagger is fine. Relevant quote:

"In the case A.P.E vs People in 2001, it was found that a knife that is less than 3.5 inches is not a weapon if the prosecution can not prove that the person intended on using it as a weapon. In the case, the defendant was found with a push knife that was less than 3.5 inches and the police charged him with unlawful carry of a concealed weapon. Prosecution could not prove that he intended to use it as a weapon and he was found not guilty of the charge."