Simplify the following text for a Grade 9 native English-speaking person.
Original: On September 26 , 1937 , Smith was seriously injured in a car accident while traveling between Memphis , Tennessee , and Clarksdale , Mississippi .
Simplified: On September 26 , 1937 , Smith was critically injured in a car accident while traveling along U.S. Route 61 between Memphis , Tennessee , and Clarksdale , Mississippi .