Duel was originally released on TV with a 70-minute runtime. For its European theatrical premiere, Spielberg added more footage to get it to a required 90 minute runtime. Some of this is new car scenes and some of it is more obvious padding (the opening credits and the conversation with Mann’s wife.) In addition to the new footage, additional directorial changes were made, including a new, dynamic mono sound mix and the removal of much of David Mann’s redundant inner monologue to great effect.
This fan edit mostly follows the original, tighter TV edit of the film, while also using the theatrical sound mix and removing the inner monologues. It also includes the further edits made to the film for the DVD and Bluray release (which removes more inner thoughts). I also created some new opening and closing title cards to match the TV edit.
I used a 4:3 HDTV copy as the base because the Blu ray is unfortunately only available in cropped 1.85:1. Special thanks to DrDre’s ColorMatch tool which was incredibly useful to help match the different sources and make the older scan look a little nicer.

Sources used:
Duel 4:3 HDTV (primary video)
Duel Blu ray (primary mono audio and color reference)
Duel NSTC DVD (used to patch out logos in the HDTV)
Duel 16:9 Cropped French Digital SD TV airing (two brief shots)
Duel TV VHS Recording (some audio)
Duel SD extras documentary (partial opening shot which was blended with the French Digital source and the Bluray)
Columbo Blu ray (pilot episodes) (opening and closing Universal logo)

Sample Images: https://imgur.com/a/lwopT

Video: 7.05 GB 1080p HD MKV
Audio: 2.0 Mono FLAC
01:13:08

Version 2 changes:

No more VHS footage (Footage from the TV cut is now sourced from a cropped French digital airing, with a custom matte to “uncrop” the opening shot.)
A different, more balanced color grade.
patched out the HDNet logos with DVD footage.
English Subtitles

Available via the 'spleen or PM.