Updated at 5:05 p.m. — A collision involving two school buses caused at least four injuries and had part of River Road blocked Wednesday afternoon. MCFRS spokesperson Pete Piringer said 10 people were evaluated and four were transported to hospitals after the crash, which according to emergency scanner traffic involved two buses from the Bullis School in Potomac. Piringer said the two students and two adults taken to the hospital had non-life threatening injuries. Two other vehicles were involved in the incident, which appeared to be a chain of rear-end collisions. Both lanes of River Road were blocked between Bradley Boulevard and New Bridge Drive shortly after the accident happened around 4 p.m. Police remain on the scene to assist with traffic control. Via TrafficLand.com