A crash avoidance system or crowding avoidance sub (CAS) may be a dedicated or adapted subassembly (sub) in a bottom hole assembly (BHA), such as somewhere above the motor and bit, or between a drill string and BHA. With data lines in a modified housing and flex lines for relative, linear, axial motion between movable parts of a single sub, sensors are contemplated to put a CAS ahead of a cushion, jar, or shock sub, even a motor. However, sensors are best connected to an Intellisys™ data connection system providing a data stream to a computer on the surface. Certain preprocessing may be done down hole, but need not be. Control of the drive system of the hook feed rate is directly controlled in real time by a data station receiving, and operating based on, certain information received from the down hole sensors of the CAS.