Have you ever wondered what those 4 numbers in the red diamond mean on the back of semi-trucks, rail cars, or tanks? Theyre codes that tell you what kind of Hazardous Material is being transported!
With this app, now you can figure out for yourself Whats in that truck!
The 4 digit codes come from the US Department of Transportation (DOT) and the Pipeline and Hazardous Materials Safety Administration (PHMSA).