(a) A person commits the offense of obstruction of highways if the person knowingly
(1) places, drops, or permits to drop on a highway any substance that creates a substantial risk of physical injury to others using the highway; or
(2) renders a highway impassable or passable only with unreasonable inconvenience or hazard.
(b) It is an affirmative defense to a prosecution under (a)(1) of this section that
(1) the defendant took reasonable steps to remove the substance from the highway; and
(2) no person suffered physical injury as a result of the presence of the substance on the highway.
(c) Obstruction of highways is a violation punishable by a fine of not more than $1,000.