The defendant-petitioners were tried and convicted by a jury in the Jefferson County Court of obstructing a roadway without a legal privilege to do so, and of disobeying the request of a peace officer to move to prevent the obstruction of the roadway in violation of sections 18-9-107(1)(a) & (b), 8B C.R.S. (1986). An appeal was taken to the Jefferson County District Court, which affirmed the convictions. We granted certiorari to determine whether the trial court erred in ruling that the defendants offer of proof was insufficient as a matter of law to provide the necessary foundation for invoking the choice of evils defense. We affirm.