Status: Anticipated
There is a major gap in U.S. research on how motorcyclists and drivers behave when lane splitting or lane filtering occurs in live traffic, and on the safety outcomes tied to these practices. Most of the discussion in the United States relies on limited domestic data and a single observational study from California, as well as international research that does not fully reflect U.S. traffic conditions.
Lane splitting is when a motorcyclist rides between lanes of slow or stopped traffic. Lane filtering is when a motorcyclist moves between lanes to reach the front of the queue, usually at intersections or in heavy congestion. Some states allow these practices, others prohibit them, and many define them inconsistently. Advocates often cite safety benefits, while law enforcement and traffic safety organizations raise concerns about increased risk and operational conflicts.
Because decision-makers must often extrapolate from non-comparable data sources, definitions and interpretations vary widely. A clearer understanding of real-world interactions between motorists and motorcyclists, and of the safety outcomes associated with lane splitting and lane filtering, is essential for developing effective driver training and public education.
This research aims to document what is currently known about the safety impacts of lane splitting and lane filtering, support the development of standardized and behaviorally grounded definitions, and create an evidence-based toolkit for state highway safety offices, driver licensing agencies and motorcycle safety programs. The goal is to provide states with practical guidance on managing the behavioral and safety complexities of these practices using reliable, U.S.-specific evidence.
