At one point, Justin Long did not show interest in returning to voice Alvin in the fourth installment of the franchise and that he would be replaced by Matthew Lillard. However, Lillard was unavailable because he was busy working on Scooby-Doo projects and after giving it a second thought, Long returned to voice Alvin once again for this film.
The only Alvin and the Chipmunks movie to be all digital, both in picture and in sound. The previous 3 movies had the chipmunks' voices treated via analog audio tape speed changes. "Road Chip" did not use any analog audio recording. All speed and pitch changes were done digitally.
Kaley Cuoco replaces Amy Poehler as the voice of Eleanor. Poehler was unable to return due to scheduling conflicts with Inside Out (2015) and Sisters (2015).
In early productions, Cameron Richardson was set to reprise her role as Claire Wilson from the first Alvin e os Esquilos (2007) film and it was her to which the chipmunks thought Dave was going to propose to, but she was removed due to some script changes and Samantha (Kimberly Williams-Paisley) takes her place.
Laura Marano: (at around 1h 6 mins) in a Miami hotel scene where Dave is staying. Laura had previously starred on Disney Channel's Austin & Ally (2011), which was set in Miami.