"Public Good", or "Tyranny"

Are speed limits a public good, or just a form of tyranny? Apparently, the answer depends on who you ask. I view speed limits from within the public goods paradigm -- that there is a conflict between the driver's desire for rapid transportation (or power tripping) and the general public's desire to avoid high-speed collisions. However, others seem to disagree and even consider it to be an altruistic act to undermine the enforcement of speed limits...implying that they view speed limits as a form of tyranny.

In this second category are the drivers who map out speed traps for Trapster. Trapster is part of the newest generation of Internet applications that rely on a community of volunteers to construct a map of speed traps for the benefit of the community of users. As far as I am aware, Trapster and similar systems provide no rewards to users who contribute information. This behavior seems to be driven by anti-authoritarian sentiments among the contributors ("F**k the police!") or perhaps by a more focused opposition to speed limits.

This issue raises a fundamental problem in the "public goods" justification for governmental action: if people disagree about whether the "public good" is actually good, then can it legitimately be considered a public good? At what point does it simply become tyranny? Some Georgists have argued that community collection of land rents would address this problem by dispersing the net value of the "public good" evenly among all citizens. I don't follow this line of thought, and am driven towards more traditional libertarian responses, either by devolving governmental power to the smallest geographic level and allowing citizens to "vote with their feet", or limiting governmental action to areas where that action is supported by almost all of the people in the jurisdiction.