If there is one thing I know from my experience in the field as a police officer, it is how litigious the United States has become. It seems we have come far from the days of simply spilling hot coffee on ourselves and blaming someone else. I have heard and seen first hand, public safety agencies who do everything right still but struggle with insurance companies and courts. The best one I have heard of is of a Police vehicle with emergency lights on while blocking traffic get demolished by an inattentive motorist. The motorist and their insurance claims the police car didn't do enough to be seen! While that one did not go far, it certainly could have.
My question to you is, are you doing everything you can to prevent easy liability claims? The obvious side of this is of course police and fire vehicles utilizing their emergency equipment and operating within their policies. By their nature it is difficult to explain how you hit a fire truck. But what about your construction vehicles, landscaping vehicles and other not-so-emergency vehicles. Are you blocking traffic on an active roadway? Are you simply throwing a traffic cone or two down and calling it good? Can you argue in court that you did all you could to prevent a traffic crash with an inattentive motorist? Only you know the amount of liability you are will to risk.
People are going to sue regardless, but don't make it easy. This will sound a little self-serving, but get at least a few warning lights to protect yourself physically as well as civilly. Even if you don't by them from us, do something to increase the safety of your job site!
Hence our unofficial motto, Be heard. Be Seen. Be safe.