[1] Dispensing with gearshift mechanical linkages has several advantages: it reduces complexity and simplifies assembly; reduces the force required to shift gears and allows it to be customized with haptic technology; allows for more interior design freedom in the placement of the gearshift mechanism; allows for automation of the engagement of the parking brake and other functions; reduces cabin noise by eliminating the acoustic linkage between the transmission and the gear shift; and by reducing floor openings it improves the crash behavior of the vehicle.
[1] With a mechanical connection, the gearshift selector always matches the engaged transmission gear.
The system needs to block incorrect input and "guide" the gearshift back to a position that matches the state of the transmission in case of error.
Safety considerations require redundancy in the gearshift and transmission sensors and in the vehicle communication network.
[1] A park by wire system engages the parking pawl of a transmission using electrical means, without the traditional mechanical system which involves linkages between the gear shifter and the transmission.