Not to digress from the main topic, but one should be careful interpreting state traffic laws from websites such as AAA (or atlases that list state-by-state rules, for that matter). The statements on law are summaries, and often leave out important information that can only be garnered from the state websites themselves. For example, if one took the AAA description on "windshield stickers" literally, it would be illegal to place a Colorado State Parks sticker (or many local parking permits) in its usual place in the lower right corner of the windshield of a car or RV. The website leaves out the important word "non-transparent" in defining what constitutes a windshield sticker as stated in the Colorado Revised Statutes, Title 42 (the park stickers are transparent). Of course, anything that actually impedes a driver's view by definition is illegal.
In regard to this particular debate, Colorado Revised Statutes, Title 42-4-215 (7) clearly indicates that hazard lights may only be used "when the vehicle is not in motion or is being operated at a speed of twenty-five miles per hour or less and at no other times". It does not exempt trucks or commercial vehicles. Bottom line is that many vehicles openly violate this ordinance, but it is not a high-priority enforcement.