These are a very good way to raise your vehicles visibility. They are noticed sometimes more by other vehicles than a dash light. I run them in all my vehicles I respond with. Some states allow them and some do not. They are not typically something you would want to install yourself unless you have a decent electronics knowledge, as well, some vehicles require special modules, and some have to be tapped into a computer harness. I would give this 5 axes on the do it yourself skills required, which means you better know what you are doing.