HAWK signals are one of many strategies to empower pedestrians trying to cross busy streets. Push the button (yes a beg button, but think of it more as a command button), and the lights, which had been flashing, change to solid red, so cars stop and you can safely and respectably cross the street. This in particular is important in the case of multi-lane roads where the center lane(s) cannot necessarily see a pedestrian in a cross-walk if the right-lane car stopped.
The literature is quite favorable in terms of pedestrian crash reductions:
- Motorist Yielding to Pedestrians at Unsignalized Intersections: Findings from a National Study on Improving Pedestrian Safety
- Safety Effectiveness of HAWK Pedestrian Treatment
The UK has a whole set of bird-like crossing signals that do similar things: