Officials in Sioux City are relying on city buses that have surpassed federal mileage standards because state and federal aid isn't sufficient to replace them.
Sioux City Transit mechanics replace engines and transmissions on the city's buses each year.
Assistant city manager Mike Collett says the constant, preventative maintenance is necessary to keep the buses in top condition.
Transit systems submit mileage readings for each of their vehicles to the Iowa Department of Transportation on July 1 of each year. The age and mileage data is compiled into a point system that determines which systems will receive money.
Once the money is gone, transit systems that didn't receive money must pay the total cost or wait until next year for another review.