Abstract
This document summarizes an analysis of data from the California Enhanced
Motorcycle
Collision Data Project. We report the prevalence of lane-splitting among
5,969 motorcyclists
who were involved in traffic collisions from June 2012 through August 2013
and examine how
other characteristics varied by whether the motorcyclist was lane-splitting
at the time of their
collision. For lane-splitting riders, we also examined how the likelihood of
head, torso, and
extremity injury varied by the manner in which they were lane-splitting.
Of the 5,969 collision-involved motorcyclists we studied, 997 were
lane-splitting at the time of
their collision (17%). Motorcyclists who were lane-splitting were notably
different from those
that were not lane-splitting. Compared with other motorcyclists,
lane-splitting motorcyclists
were more often riding on weekdays and during commute hours, were using
better helmets,
and were traveling at lower speeds. Lane-splitting riders were also less
likely to have been using
alcohol and less likely to have been carrying a passenger.
Lane-splitting motorcyclists were also injured much less frequently during
their collisions. Lanesplitting
riders were less likely to suffer head injury (9% vs 17%), torso injury (19%
vs 29%),
extremity injury (60% vs 66%), and fatal injury (1.2% vs 3.0%).
Lane-splitting motorcyclists were
equally likely to suffer neck injury, compared with non-lane-splitting
motorcyclists.
We also examined how the manner in which riders were lane-splitting affected
their likelihood
of being injured for each of the three injury types using multivariate
regression methods. We
found that both traffic speed and motorcycle speed differential (the
difference between
motorcycle speed and traffic speed) were important in predicting the
occurrence of injury.
There was no meaningful increase in injury incidence until traffic speed
exceeded roughly 50
MPH. Motorcycle speed differential was a stronger predictor of injury
outcomes. Speed
differentials of up to 15 MPH were not associated with changes in injury
occurrence; above that
4
point, increases in speed differential were associated with increases in the
likelihood of injury
of each type.
Lane-splitting appears to be a relatively safe motorcycle riding strategy if
done in traffic moving
at 50 MPH or less and if motorcyclists do not exceed the speed of other
vehicles by more than
15 MPH. A significant number of motorcyclists lane-split in fast-moving
traffic or at excessive
speed differentials. These riders could lower their risk of injury by
restricting the environments
in which they lane-split and by reducing their speed differential when they
do choose to lanesplit.
----------- the whole study:
http://www.ots.ca.gov/pdf/
2015.pdf
