(1) http://en.wikipedia.org/wiki/Semi-trailer_truck
(2) http://www.worldwatch.org/node/5443
(3) http://geography.about.com/library/faq/blqzcircumference.htm
Calculations:
1961: 71MT / 20T load = 3.55M x 16.75metre lorries = 59.5M meters or 59,463 km /40,075km around equator = 1.48 times
2007: 275MT / 20T load = 13.75M x 16.75metre lorries = 230.3M meters or 230,300 km /40,075km around equator = 5.75 times
2050 forecast: 465MT / 20T load = 23.25M x 16.75metre lorries = 389.44M meters or 389,438 km /40,075km around equator = 9.71 times
