MI HB4423

Establishes basic speed law requiring vehicles to operate at careful and prudent speeds not greater than what allows safe stops within visible distance ahead.

Sets specific speed limits for different road types: 15 mph in mobile home parks, 25 mph in business districts/parks/residential subdivisions, 30-45 mph on highways based on vehicular access point density, and 35 mph for heavy trucks during reduced load periods.

Requires speed limit signs to be properly posted and traffic control orders filed with county/city clerks, with exceptions for residential subdivisions and certain highway segments.

Mandates the state transportation department and department of state police increase speed limits on at least 600 miles of limited access freeways to 75 mph and 900 miles of trunk line highways to 65 mph within one year if engineering studies support the increases.

Repeals Section 629 of the Michigan Vehicle Code and makes the act conditional upon enactment of House Bills 4424, 4425, and 4426.