Complex sentence: The car in which he was travelling as a passenger had a head-on collision with one driven by Peter Metcalfe and his 17-year-old girlfriend, Helen Read, who also died in the accident.
Split into simpler sentences: The car in which he was travelling as a passenger had a head-on collision with one driven by Peter Metcalfe. Metcalfe's 17-year-old girlfriend, Helen Read, also died in the accident.