Portugal based road safety firm Sernis has unveiled a new technology for solar studs ? the i-stud. The new technology has been applied to existing SR-i15 and SR-i120 studs and enables them to work even during severe winter with very little sunlight. A microcontroller inside each stud gives various features and options including setting the studs in sleep mode to prevent discharge of the battery. The i-stud is able to adapt to brightness and regulate its light level in line with the energy with which it was charged during the day. A working period function allows the user to set up the number of hours the i-stud works after it detects the onset of night. This is helpful for roads and other facilities where studs need not be operational all night, thus helping save energy. An operation mode function enables users to switch the mode between ?flashing? and ?always on?, whereas in conventional studs this switch cannot be done without replacing the studs.