The problem with your presumption that authority is good, is that it assumes the authority is somehow better at making decisions for an individual than the individual is.

There is research which shows that the trend towards higher vehicular weight is caused by drivers desire to be, or at least feel, safer. Yet this makes less economically fortunate drivers less safe, has adverse impact on the environment, and doesn't improve human welfare.

Why do we regulate helmets and not vehicular weight? It might have less to do with improving welfare and more to do with individual politics. I fear people have more of a tendency to want to be an authority over personal liberties than of unwarranted aggressions. For example, how long have people protested gay relationships, but allowed sexual harassment to persist?