A USA Today investigation has shown that port trucking companies frequently put out “hundreds of impaired drivers on the road” who are driving with little to no sleep. This is in clear violation of federal safety regulations, and puts thousands of fellow drivers at risk every day.

Technically, there is currently no accurate tracking system available to track commercial truck movements nationwide. USA Today instead worked with publicly available information to build a tracking system after the fact.

USA Today’s investigation tracked the movement of Los Angeles area trucks going back four years, retracing their time stamps every time a truck passed through a port gate. With this data, the reporters were able to calculate exactly how long each truck was in operation, and also cross checked this information against federal crash data from 2013 to 2016. The results were fairly staggering.

On average, trucks operating in the Los Angeles area operated “470 times a day without the required break.” These trucks were involved in at least “189 crashes within a day of an extended period on the clock.” With some exceptions, the federal regulations say commercial truck drivers should take a 10 hour break approximately every 14 hours.

Instead, the USA Today investigation showed that there were approximately 580,000 instances of trucks on the road for at least 14 hours without any evidence of a 10 hour break, a clear violation of federal regulations. Without a live, accurate tracking system, however, it can be difficult to impossible to enforce these violations until after tragedy has already struck.