A bike box is a green area marked within the motor-vehicle lane, containing a white bicycle symbol. A section of green bicycle lane often precedes the box.
Bike boxes are used at intersections to designate a space for cyclists to wait at a red light. Cyclists stop in front of motorists and can proceed through the intersection first when the light turns green. Bike boxes increase cyclist visibility and reduce the risk of “right hook” collisions.
At many intersections where bike boxes have been implemented, right turns during the red signal phase are prohibited. This is indicated with a “no right turn on red” sign. If the intersection does not contain a “no right turn on red” sign, motorists are permitted to turn right on red when safe to do so.
What cyclists should know:
When a traffic signal is yellow or red, enter the bike box from the approaching green bike lane. Stop before the crosswalk. When the light is green, proceed as normal. Be aware of right-turning motorists, especially while in the intersection.
What motorists should know
When the traffic signal is yellow or red, motorists must stop behind the green bike box at the white stop line.
When the light turns green, motorists and cyclists may move through the intersection as usual, with cyclists going first. Motorists turning right on green should signal and watch for cyclists to the right.
If right turns on red are permitted
If right turns on red are not prohibited, motorists must make an initial stop at the white stop line behind the green bike box. If no cyclists are present, motorists may then carefully ease forward through the bike box to make their right turn.
In this case, motorists would treat the bike box like a crosswalk that requires motorists to yield if pedestrians are present, but allows motorists to ease forward to make a safe turn with full visibility if pedestrians (or cyclists, in the case of the bike box) are not present.