This StreetsWiki entry is rounding into encyclopedic form quite nicely. Andy Hamilton, DianaD (who also brought us the VMT entry last week) and Streetsblog’s own Aaron Naparstek have been piecing together a detailed look at the history and effectiveness of bike boxes:

With nearly 40% of daily commuter trips taken by bike, Copenhagen,
Denmark is generally considered the world’s most bicycle-friendly city.
Having been working with bike boxes for nearly 20 years, studies by
Danish road engineers and transportation planners have found that bike
boxes significantly reduce the number of crashes between right-turning
motorists and bicyclists going straight through the intersection.
The City of Copenhagen has concluded that bike boxes are most effective
when combined with a brightly colored lane continuing straight through
the intersection to help alert right-turning motorists to the fact that
bicycle riders may be traveling straight through the intersection along
their right side[9].

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