Rear-View Mirrors timeline.

Jan 1, 1911

At the first Indy 500 in 1911, race winner Ray Harroun’s car used a device for the first time that has since become standard equipment on all cars – the rear-view mirror.

http://sports.yahoo.com/irl/news?slug=bm-indyinnovation051808
Jan 1, 1968

Rear-view Mirrors become required by law
Jan 1, 1993

The Federal Government revised the requirements on school buses

At the first Indy 500 in 1911, race winner Ray Harroun’s car used a device for the first time that has since become standard equipment on all cars – the rear-view mirror.