The latest incident occurred late Monday night when a Cadillac and then a Ride On bus struck a woman walking south on I-270. Maryland State Police say the unidentified woman died at the scene.
Earlier Monday, a woman pushing her 3-year-old son in a stroller was struck by a car at the intersection of University Boulevard and Sligo Creek Parkway just after 3 p.m., Montgomery County Police say.
They were taken to a nearby hospital with serious, but non life-threatening injuries. The mother and son were in a crosswalk at the time.
Minutes after the University Boulevard incident, a 14-year-old boy was struck by a Gaithersburg City Police car on Darnestown Road near Quince Orchard Boulevard.
The boy was trying to cross the street from the median. He was taken to the hospital with minor injuries.
On Monday morning, a pedestrian was also injured on Burke Center Parkway in Fairfax County Monday morning.
Last week, four people died and two were injured in pedestrian accidents across the region.
WTOP's Hank Silverberg contributed to this report.
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