A system for automatically controlling power supply to a lamp (101) of a vehicle, the system comprising: a detection module (20) to detect whether the vehicle is stationary or non-stationary; a controller (102) to receive a signal (25) having a first value transmitted by the detection module (20) when the vehicle is detected as stationary, and the controller (102) to receive a signal (25) having a second value transmitted by the detection module (20) when the vehicle is detected as non-stationary, wherein if the signal (20) having the first value is received by the controller (102), the controller (102) reduces the power supply to the lamp (101) from a first power level to a lower second power level in order to reduce energy consumption of the lamp (101), and if the signal (25) having the second value is received by the controller (102), the controller (102) restores the power supply to the lamp (101) from the lower second power level to the first power level.