RTD's train from Union Station to Denver International Airport on a test run.

(Hart Van Denburg/CPR News)

University of Colorado's president is defending a $5 million deal for naming rights on the train line to Denver International Airport in response to critics who say the university's funds should have been spent elsewhere.

President Bruce Benson told the Denver Post the deal with the Regional Transportation District is part of increased marketing efforts to bring more attention to the university and secure its future.

As part of the deal, a video about CU's four campuses will be shown in the trains that run between the airport and Union Station. RTD has also agreed to allow advertisements on buses running between Denver and Boulder.

Benson says the money for the deal will come from his own discretionary funds and interest earned from the university system's investments.