trunk. Dating back to the very early years, the pace cars were often painted with special liveries complete with logos, lettering, pinstriping, and other decorative markings. In addition, sometimes flagpoles, lights, and other motoring paraphernalia were installed to further identify the pace car. Most manufacturers used the opportunity to showcase their higher end or luxury models. Since in the early years, the pace car was only used for one lap at the start (and not during caution periods), the need for a high performance machine (i.e., sports car) was not necessarily the top priority. In many years, the pace car was a convertible, which along with increasing the luxury status of the vehicle, it aided in the officials' ability to marshal the start. 1957–1976 In most years through the early 1950s, the pace car led the field around the track for one warm up lap, and then the race began. The pace lap concept was popular with fans, as many drivers commonly waved at the fans and the rolling grid made for spectacular photographs. By 1957, the procedure was changed so the pace car led the field for two warm up laps. This allowed extra time to warm up the engines, oil temperatures, and tires, and allowed the drivers the chance to survey the conditions of the entire track at least once before receiving the green flag. This also allowed the fans on the main stretch (where the largest grandstands are located) to see the entire field parade by one time before the start. Previously only fans on other parts of the track got to actually see the grid go by for photographs and waving. For the 1957–1958 races, the grid was lined up and exited single-file from the newly constructed pit lane. The two laps allowed the field to properly form up, however, in practice it turned out to be difficult and both races saw incidents at the start. In 1959, the field went back to lining up the grid on the main stretch, and continues to do so to this day. By the late 1960s, not only would a special driver be behind the wheel of the pace car, but numerous celebrities would be invited to ride along as passengers. Automotive executives, NASA astronauts, reporters from ABC Sports and the IMS Radio Network, and other celebrities were among those invited to ride in the pace car. In 1971,