BOULDER, Colo. -

Transportation officials say they plan to increase the threshold for a high occupancy vehicle, or HOV, from a minimum of two occupants to three along the stretch of U.S. Highway 36 between Denver and Boulder.

The Daily Camera reports the change will take effect when the highway improvement project on U.S. 36 is completed sometime in the beginning of 2016.

Nick Farber with the Colorado Department of Transportation says HOV3 will become the standard in the state starting in four years. Its debut is slated for the $425 million U.S. 36 project, as well as the existing express lanes on Interstate 25 north of downtown Denver.

One of the goals of the U.S. 36 project is to provide reliable travel time for buses between Denver and Boulder.