After high school, Adler attended Johns Hopkins University to study engineering, but after continuing to struggle with academics, he dropped out 2 years later.

[2] In 1919, Adler began working for the Maryland and Pennsylvania Railroad (also known as the Ma&Pa) as a telegrapher and assistant station agent.

In response, Adler designed a system that contained a warning light connected in parallel to the standard bells.

In his design, he created an automatically triggered system that flashed two lights alternatively in a wigwag pattern when a train was approaching.

This invention, called the Adler Flashing Relay, received the American Railway Association’s endorsement and was later adopted by over 40 railroad companies.

After the success of his projects, Adler left the Maryland and Pennsylvania Railroad to pursue invention full-time.

Adler’s system was composed of a series of bar magnets buried under the road 20 meters away from dangerous spots.

Adler contacted 600 newspapers, magazines, and engineering journals, including Science Monthly and the New York Evening Post, to run stories on his system.

[2] On February 4, 1929, Adler installed a pedestrian push button at the intersection of Charles Street and Cold Spring Lane in Baltimore.

His motto was “If they can save lives, I want everyone to have them.” Adler often donated his patents to the government free of charge so that they could be publicly used and help more people.