The specific category of sexual tension experienced when on a trip with colleagues/ coworkers/ fellow students.
This type of tension usually results from unconscious excitement due to a new environment and a desire to avoid being alone in a travel-related situation (such as a bus ride or a tour).
The results of trip tension can be anything from a one time hook up to a full fledged relationship (or a distinct feeling of loneliness for those who fail to find someone compatible and also experiencing trip tension).
"Dude what?? When did Jim and Cindy start hanging out?"
"They just got back from the DC trip. Classic case of trip tension."