The tightest parallel park is 14 cm (5.51 in) and was achieved by Ronny Wechselberger aka Ronny C' Rock (Germany), at Flugplatz Kindel in Eisenach, Germany, on 18 June 2012. The feat was recorded for the TV show GUINNESS WORLD RECORDS - Wir holen den Rekord nach Deutschland, aired on RTL2 (Germany).
Ronny used a VW Up with a length of 3.54 m (11 ft 7.37 in), which he parked into a 3.68-cm-long (12 ft 0.88 in) space, marked by two other Up's. The distance was measured electronically with a laser device as well as a measuring tape.
Comments below may relate to previous holders of this record.