The minor crash occurred when DiCaprio and Agdal, who were driving a friend's car, were rear-ended by a Mini Cooper. The crash resulted in little damage to DiCaprio's vehicle and extensive damage to the Mini.
Witnesses say that after the crash, DiCaprio first made sure Agdal was okay before getting out of the car to check on the woman driving the Mini Cooper.
"She was shaken up," a witness said of the other driver. "Leo was nice about it. He motioned for her to come with him, and he helped her over to the guardrail so she could rest."
Although the woman was reportedly uninjured, an ambulance was called to the scene "as a precaution," and a source tells PEOPLE that "all are doing great" after the incident.
DiCaprio, 41, and Agdal, 24, have been romantically linked since July.