  Lane-changing is a critical maneuver of vehicle driving, and a comprehensive
understanding of its impact on traffic is essential for effective traffic
management and optimization. Unfortunately, existing studies fail to adequately
distinguish the impact of lane changes from those resulting from natural
traffic dynamics. Additionally, there is a lack of precise methods for
measuring the spatial extent and duration of the impact of a single
discretionary lane change, as well as a definitive metric to quantify the
overall spatiotemporal impact. To address these gaps, this study introduces a
quantitative indicator called the Corrected Travel Distance Bias (CTDB), which
accounts for variable speeds due to inherent traffic dynamics, providing a more
accurate assessment of lane-changing impacts. A comprehensive methodology is
developed to compare vehicle trajectory data before and after lane-changing
events, measuring both the magnitude and spatiotemporal extent of the
lane-changing impact. The results, based on the Zen traffic data from Japan,
indicate that the impact of a lane change in the target lane lasts an average
of 23.8 seconds, affecting approximately 5.6 vehicles, with a CTDB value of
-10.8 meters. In contrast, in the original lane, the impact lasts 25 seconds,
affects 5.3 vehicles, and yields a CTDB value of 4.7 meters.
