Turns, Lane Changes, and Offtracking
Turns, Lane Changes, and Offtracking
This domain tests your ability to place a long vehicle in a lane and around a corner - the geometry of offtracking and the mirror work that goes with it.
Right turns
Swing wide enough that the trailer's rear wheels stay clear of the curb, but not so wide that you cross into oncoming lanes. The trailer cuts the corner, so its rear wheels track several feet inside the tractor's path - more for a 53-foot trailer. Watch the right mirror through the whole turn, and check for pedestrians, cyclists, and cars that may pull into the gap on your right.
Left turns
At the start of a left turn the rear of the trailer swings out to the right. Before starting the turn, check the right mirror for a vehicle that could be hit by that swing.
Lane changes
Signal early, check both mirrors and the blind spot, and confirm the whole trailer is clear before moving. Make one smooth, gradual movement. Abrupt lane changes at highway speed produce rearward amplification, and the trailer can swing into the next lane or onto the shoulder.
Speed
Take turns below the posted advisory speed; a combination stable in a straight line can roll over in a curve at a speed a car handles easily.
Worked example. You are turning right at a tight urban corner. If you start the turn with the tractor close to the curb, the trailer's rear wheels will track inside and strike the curb or a sign. Setting up 3-4 feet from the curb and turning later keeps the trailer's wheels clear, and the right mirror confirms the gap.
Traps that cost marks. Swinging so wide that a car fills the space on your right; watching only the left mirror in a right turn; changing lanes abruptly at speed; entering a turn too fast and braking in it.