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YARD

1)  A system of tracks branching from a common lead or ladder track, with defined limits, used for switching, making up trains, or the storing of cars.  2) An area near the terminal used for the staging and storage of trailers.

 

YARD JOCKEY

Truck used to move or jockey rolling equipment in or about truck terminal or yard.

 

YAW

The maximum rate change of direction for a vehicle; a sidewise movement of a vehicle in turning; Movement of a vehicle in another direction than that in which it is headed; sidewise motion produced when centrifugal force exceeds traction force.  Often the result of overreaction or exceeding the critical speed.  Sometimes revealed by tire marks on the roadway.

 

YAW INSTABILITY

The lateral acceleration rate at which a vehicle will begin to yaw.

 

YAW MARK

The physical  mark on the roadway caused by the rotating  tires of a vehicle during a maximum rate change  of direction (turn).  Yaw marks are also called scuff marks.

 

YAW VELOCITY

(r)  The angular velocity about the z-axis.

 

YAWING MOMENT COEFFICIENT

(C M z)  is based on the yawing moment deriving from the distribution of aerodynamic forces acting on the vehicle.