The Oregon Department of Transportation
has undertaken a review of literature on lane-sharing, the practice
of splitting lanes of traffic on a motorcycle, but the review fails
to come to any real conclusion.
The department noted that increasing
motorcycle and other traffic, and potential benefits of lane-sharing
to traffic movement patterns, make the issue worth considering, but
in its review it found that there was very little study of
lane-sharing benefits and problems.
The obvious benefits of lane-sharing
include reducing congestion and travel times, increasing reliability,
and reducing emissions, the review paper, finished in June, stated.
However, it notes that "while these benefits are frequently cited,
their value has rarely been quantified," and "the degree to which
a motorcycle impacts congestion, relative to a car, is not well
measured, especially when lane-sharing is practiced."
The review says that law enforcement
finds lane-sharing is useful in emergency situations.
In North America, lane-sharing is only legal in
California, where it’s legal by default-no law has been written to
ban the behaviour.
The Hurt Report is cited as the most
frequently noted study, but that 1981 paper did not directly examine
lane-sharing as a causation factor in crashes, and the California
Highway Patrol does not include lane-sharing among its approved list
of crash causes.
Lane-sharing is widely allowed in
Europe, and has been studied there. The MAIDS report, for instance,
found it to be a factor in a small percentage of collisions, and
largely because drivers in stopped or slowed cars do not expect a
motorcycle to be moving near them, and may suddenly turn into the
The Oregon study does not form a solid
conclusion, but leaves room for further study. "It is clear that
additional research on lane-sharing is needed," the paper says.
"Little information currently exists; most of which is part of
large crash studies where lane-sharing is not the primary focus."
See the review paper yourself at