holstein13, someone decided to fight a ticket for violating the speed limit while towing another motor vehicle and won because the law and the speed limit signs said "Vehicles towing TRAILERS". The law now states "ALL vehicles towing" are restricted to 55MPH.
The 3 axle sign says Vehicles with three or more axles" the speed is 55 MPH, while in fact the law excludes Motor Homes and MOST buses from the 55MPH restriction. School Buses are limited to 55 in all cases.
I believe that you are allowed to use the #1 lane up to 1.5 miles before a left exit or a split("y") in direction. It may be two miles. There are little nuances to that law but I know you're safe at 1.5 miles and probably 2.0 miles. Even our legislature knows drivers of 4 wheelers don't like to have Semi's in front of them and allow you to get over for left exits in pleanty of time.
