As in all automobiles, 4 wheels are the preferred solution due to added stability and better load distribution characteristics.
3 wheels configuration can be adapted for smaller vehicles with the main motive of reducing rolling resistance and drag.
Within the current framework and regulations for road legal vehicles it would require a huge step to design and legalise a 3 wheel automobile, but taking into consideration future generation infrastructure and with that possible change in regulations unorthodox drivetrain and wheel configuration can be studied.