Page "Train Protection & Warning System" Paragraph 1

Unlike ATP, it does not aim to stop trains at or before a signal that is at " danger "-it aims to stop the train before the point at which a collision with another train could occur, excluding rear-end collision with a train in front.

According to the UK's Health and Safety Executive, TPWS is estimated to prevent between 65 % and 80 % of fatalities that would be stopped by a full ATP system.