What was the first car to use flashing electric turn signals?

The first application of a flashing electric turn signal was used on the 1938 Buick as a new safety feature. It was advertised by Buick as the “Flash-Way Directional Signal”. By 1940, Buick added the self-canceling mechanism attached to the steering column. This complex and sensitive mechanical method of springs, cams, sliders and lobes with fixed shut-off points is still used worldwide in virtually all vehicles. This was indeed an ingenious solution in 1940 and has worked well enough to get by for many years.