Northern Virginia is ending a program that provides free bus rides on bad air quality days.

The Northern Virginia Transportation Commission said Thursday that it voted against using federal grants to fund the RIDE FREE bus program on Code Red days. The service encouraged residents to drive less in an effort to cut down on emissions.

Transportation leaders say the program costs northern Virginia more than $2.5 million each year.

Stuart Freudberg of the Metropolitan Washington Council of Governments says air quality has improved since the program started. He says Montgomery, Prince George's and Frederick counties in Maryland will likely continue the service this season.