H.A.W.K. Signal
A HAWK beacon (High-Intensity Activated crossWalK beacon) is a traffic control device used to stop road traffic and allow pedestrians to cross safely. It is officially known as a Pedestrian Hybrid Beacon (PHB). The purpose of a HAWK beacon is to allow protected pedestrian crossings, stopping road traffic only as needed. Where standard traffic signal ’warrants’ prevent the installation of standard three-color traffic signals, the HAWK beacon provides an alternative.
A HAWK beacon is used only for marked crosswalks. Similar hybrid beacons are allowed at driveways of emergency service buildings, such as fire houses.

For more information, you can read the CDOT Informational Brochure (PDF).