This is a quite interesting 1950 film called Wisconsin 1000 Rescue Squad. It chronicles the early history of the Bethesda-Chevy Chase Rescue Squad in Montgomery County, Maryland, which dates back to 1937. Here's what the BCC's website says about the film:
In 1950 the U.S. Department of State produced a film about the Squad entitled "Wisconsin 1000 Rescue Squad," named after the Squad’s 24-hour emergency telephone number. The State Department eventually printed the film in ten different languages and circulated it around the world.