I agree. This issue really shows up because we have so much public property and common areas coupled with democracy. Public property owned by the government is itself a violation of the NAP, as taxes taken to pay for such property are a violation of the NAP.

If you were speeding on a private road then you have violated your contract. Assuming the contract allows the private road owner to detain you and fine you for speeding, they could stop you for the violation.

If you were speeding on unowned land, what right would another have to stop you, detain you, and take your money? None.

everything the state does is backed up by the threat of violence.

This statement is true whether it is a law regarding speeding or any other area of enforcement. It should really make us question when the use of force is appropriate. The answer should be only in defense of human rights.