Opposition to speed limits divides an audience. Most immediately shut down to anything you have to say and call you crazy, and the others listen because they’re annoyed with speed limits but are still very skeptical.
After all, speed limits are one of those things like food label warnings, fire exits, and health insurance that might save our lives. And because we want our lives to be saved, we want to make an absolute rule that all lives get saved the same way. Fear creates absolutes.
This is a type of broken reasoning where humans are both cause and effect of all that happens in their world. The ultimate goal, or effect, is to preserve ourselves. So we create rules to preserve all people as that guarantees us both preservation and the approval of others.
However, we’re unable to think beyond that moment to the effect of preserving everyone from themselves, and we’re also unable to think before that moment to the reason that different categories of activity — say, driving fast — have different results for different people. Some people are better drivers.
Looking past this confusion of cause, effect and self, we can see that speed limits have a number of problems: http://www.amerika.org/2009/social-reality/bad-logic-speed-limits/