In case of locally monitored level crossings trackside signals are located on the line ahead of the level crossing. They inform the train engine driver whether the level crossing has been closed and may be entered.
The signal indication that a level crossing may be entered is only activated by the control unit when the level crossing has been technically protected. Dependant on the layout of the level crossing this means that the red roadside signals are ON or the barrier arms are lowered. The basic signal pattern remains unchanged if the crossing is not protected. In Germany two different types of signal are available: BUE0/1 with flashing light and So16 with steady light.
Safety can be enhanced with the aid of an inductive train protector (known as INDUSI), the use of which is obligatory on German Railway (DB) lines with a speed of more than 50 km/h. This device causes the train to be stopped if it overruns a signal which has not been cleared. A corresponding magnetic coil is fitted in the track for this purpose.