The 41st International 500-Mile Sweepstakes was held at the Indianapolis Motor Speedway on Thursday, May 30, 1957. The event was part of the 1957 USAC National Championship Trail, and was included in the 1957 World Drivers Championship.

Sam Hanks won the Indianapolis 500 in his thirteenth attempt (the most such by any 500 winner). He retired from competition at Indy in victory lane. Contrary to popular belief, Hanks did not completely retire from racing until the end of the year. He skipped the Race of Two Worlds when his entrant withdrew, but competed in events later in the year, winning the event at Trenton, and finished third in points championships for 1957.

Hanks received a record $103,844 purse, the first driver to win a $100,000 single-race payday. The total race purse was also a record, over $300,000 for the first time.

Hanks won the race in George Salih's "Lay-down Offy". The Offenhauser engine was mounted on its side and shifted off-center. This was done in order to lower the center of gravity, reduce frontal area, and counterbalance the body roll in the turns. The car that Hanks drove for the win in 1957 would win back-to-back Indy 500s, with Jimmy Bryan piloting the very same chassis to victory again in 1958.

For 1957, the Speedway introduced a new state-of-the-art pit lane and brand new Master Control Tower to house broadcasting as well as timing and scoring. For the first time, the pit area was separated from the mainstretch by an inside wall. The pit lane was paved in concrete (the mainstretch remained brick), while a grass strip went the length of the pit road to accommodate pit crew sign board men. Flagging duties would be done from a station on the grass strip at the start/finish line, and eventually a small wooden platform would be constructed for the flagman to stand atop. USAC officials also stationed themselves on the new grass parapet.

For the 1957 race, the field lined up in the pit area single-file, rather than the traditional eleven rows of three on the racing surface. On the pace lap, the field assembled into position, and was aligned for the green flag. By 1957, the field was now being taken around for two warm-up laps (one "parade" lap, and one "pace" lap), an increase over the single lap used previously. This single-file grid practice would eventually lead to confusion, and was utilized for only two years.

...
Wikipedia