The car that crashes into the ER is an early 1980's Oldsmobile Delta 88 four-door sedan.
First episode where Nancy Stafford (Joan Halloran) and Mark Harmon (Dr Robert Caldwell) join the main cast, although Harmon doesn't appear until the next episode.
For the first season, recurring actors Norman Lloyd (Dr Daniel Auschlander), Ellen Bry (Nurse Shirley Daniels), Eric Laneuville (orderly Luther Hawkins), and Kim Miyori (Dr Wendy Armstrong) were all credited as guest stars. Starting with this episode, they all join the main cast.
With this episode, Norman Lloyd (Dr Daniel Auschlander) joins the main cast. His character was announced to have liver cancer in the pilot episode, and it was originally intended that he would die or be written out after four episodes. However, he proved to be popular with fans, and so was kept as a recurring character, with his cancer in remission. He would remain for the run of the series. By a remarkable coincidence, Lloyd himself turned out to have incredible longevity, acting until he was 100 (Trainwreck (2015)) and living to the age of 106.