Earlier this month I met with a gentleman that was stopped waiting to take a left turn onto a main roadway. To his left was a large bush. In front of him was another vehicle facing the opposite direction at a stop sign. The other vehicle "waived" him to take his left turn indicating it was safe. It was not safe. Coming the opposite direction was a vehicle that, according to the gentleman, had veered around a garbage bag in the middle of the street (you can't make this stuff up). According to the police report the other driver was in his correct lane. Crash ensued.
I can't tell you how many times someone has come to my office wanting to sue the person that waive them through. A really bad fractured ankle case comes to mind where my client was the victim of the incorrect waiving. The first issue is that nobody ever gets the information on the person that waived them through. They aren't listed on police reports because they leave the scene. That, plus who is going to admit that they were wrong and waived someone into traffic? That is the first problem. The second problem is that you can't rely on a third party to make driving decisions for you. As such, suing them would be a waste of time.
The other thought this potential client had was suing the government for failing to make the bush trimmed. The problem here is that suing people is expensive so you must be really hurt. Suing the government is very expensive and there is the issue of sovereign immunity. In this circumstance the damages would not have offset the costs of litigation thus making it a bad situation for the potential client.
Long and short: DON'T TRUST OTHER DRIVERS