This practice is common in North America. It is also terribly confusing. and unsettles many travellers from the rest of the world. The practice is not uniform: some places let you turn right on a red light, while other places make it expressly forbidden.

The rule: unless there is a sign to the contrary, you can turn right at a red traffic light throughout the USA and Canada except for New York City and the Province of Québec. In NYC you also see some intersections that explicitly permit turns on red (this being an exception to the city-wide no-turn-on-red rule). In any case, you must come to a complete stop and check that the road is clear before making a right turn on a red light.

For reference, the practice was introduced as a gasoline saving measure in the 1970s.