one every 15 seconds for a time trial, as a start from a full grid was not possible on the tight and twisty roads. Although the public road circuit used for the Targa was extremely challenging- it was a very different kind of circuit and race from any other race on the sportscar calendar. All of the circuit variations of the Targa had so many corners that lap speeds at the Targa never went higher than 80 mph (128 km/h), as opposed to Le Mans in France, where cars would average 150+ mph (240+ km/h) or the Nürburgring, where cars would average 110 mph (176 km/h). Helmut Marko set the lap record in 1972 in an Alfa Romeo 33TT3 at 33 min 41 s at an average of during an epic charge where he made up 2 minutes on Arturo Merzario and his Ferrari 312PB. The fastest ever was Leo Kinnunen in 1970, lapping in the Porsche 908/3 at or 33 min 36 seconds flat. Due to the track's length, drivers practised in the week before the race in public traffic, often with their race cars fitted with license plates. Porsche factory drivers even had to watch onboard videos, a sickening experience for some. The lap record for the 146 km "Grande" circuit was 2 hours 3 min 54.8 seconds set by Achille Varzi in a Bugatti Type 51 at the 1931 race at an average speed of . The lap record for the 108 km "Medio" circuit was 1 hour 21 min 21.6 seconds set by Varzi in an Alfa Romeo P2 at an average speed of at the 1930 race. The fastest completion around the short version of the island tour was done by Giovanni "Ernesto" Ceirano in a SCAT at the 1914 race, completed in 16 hours, 51 minutes and 31.6 seconds from May 24–25, 1914. The fastest completion of the long version of the island tour was by Mario and Franco Bornigia in an Alfa Romeo 6C 2500 Competizione, completed in 12 hours, 26 minutes and 33 seconds flat at the 1950 race at an average speed of . 1970s, safety and demise In the late 1960s and early 1970s, race cars with up to 600 hp (450 kW) such as Nino Vaccarella's Ferrari 512S raced through small mountain villages while spectators sat or stood right next to, or even on, the road. Porsche, on the