Bike Boxes: Good Idea?

In light of the new Market Street bike boxes, the SFMTA has provided a handy infographic on how to safely use them:

In their press release, the SFMTA said that bike boxes are "designed to improve the visibility and positioning of bicyclists at intersections with traffic signals and to prioritize bicycles as they move through intersections. Bicyclists stopped in a bike box are easily seen by motorists, improving safety at intersections. Bike boxes provide a separated waiting area for bicyclists and can increase pedestrian safety by improving visibility and decreasing both motorist and bicycle encroachment into crosswalks."

Also included in the press release was additional guidelines to using these bike boxes. Whether you bike, walk, or drive, it's very important to know these rules.

What Motorists Should Know

When the traffic signal is red, motorists must stop behind the white stop line behind the green bike box. Motorists should not stop on top of the bike box, but rather keep it clear for cyclists to use. Right turns on a red signal will not be allowed at these intersections.

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.

What Bicyclists Should Know

When a traffic signal is red, bicyclists must enter the bike box from the approaching bike lane and stop before the crosswalk.

When the light is green, bicyclists should proceed as normal through the intersection. Bicyclists should be aware of right-turning motorists, especially while in the crosswalk and the intersection.

What are your thoughts on these bike boxes? Do they seem more helpful than potentially harmful?