DENVER (CBS4)– The Denver International Airport could be losing out on revenue from Uber and Lyft after a city audit revealed where the ride-sharing services could be shorting the airport.

Right now, the ride-sharing companies pay monthly fees to the airport based on ride volumes.

Denver International Airport (credit: CBS)

Those companies are self-reporting the number of rides because DIA doesn’t use electronic tag systems on them. That means the airport could be missing out on tens of thousands of rides.

(credit: CBS)

The city auditor says the airport needs to look into new tracking systems like those in San Francisco and Atlanta to get a more accurate number of trips.

(credit: CBS)