Missouri Revised Statutes Title XIX. Motor Vehicles, Watercraft and Aviation § 304.705. Certain trucks not to drive in far left lane of certain interstate highways (St. Charles and Jefferson counties)

1. In any county with a population of more than one hundred eighty thousand inhabitants that adjoins a county with a charter form of government with a population of more than nine hundred thousand inhabitants, all trucks registered for a gross weight of more than twenty-four thousand pounds, as of January 1, 2008, shall not be driven in the far left lane upon an interstate highway having at least three lanes proceeding in the same direction, within three miles of where an interstate highway and a three-digit numbered Missouri route intersects with an average daily traffic count on the interstate highway of at least one hundred thirty thousand vehicles at such point. The Missouri department of transportation shall design, manufacture, and install any informational and directional signs at the appropriate locations. Such restriction shall not apply when:

2. As used in this section, “truck” means any vehicle, machine, tractor trailer, or semitrailer, or any combination thereof, propelled or drawn by mechanical power and designed for or used in the transportation of property upon the highways.

3. A violation of this section is an infraction unless such violation causes an immediate threat of an accident, in which case such violation shall be deemed a class C misdemeanor, or unless an accident results from such violation, in which case such violation is a class A misdemeanor.