When referring to cars, the left-hand side of the car is the side that corresponds with the driver's left, as seen from the driver's seat.
In front-wheel-drive cars with longitudinally mounted engines, most often the front of the engine will point towards the front of the car, but some manufacturers (Saab, Citroën, Renault) have at times placed the engine 'backwards', with #1 towards the firewall.