Lane filtering is when a motorcycle or small vehicle moves between lanes of slower or stopped cars, especially during traffic. In the Philippines, lane filtering is not clearly illegal, but LTO Administrative Order 2008-015 states that motorcycles must observe one lane per vehicle only.That means weaving between vehicles may be considered a violation, especially if done recklessly or without signaling. On expressways, lane filtering is explicitly prohibited by DPWH Department Order No. 123 s. 2001.While commonly practiced, it’s still risky because:Other vehicles may not see the motorcycleThere's limited space for sudden movementIt can cause side collisions or disputes