during the weekends, trolleybuses on route 13 are operated only on its western branch (via lame-borgo panigale), where they have to run on battery for a short while between porta san felice and via lame, as the wires continue straight to via ugo bassi. it is not possible to use trolleybuses on the eastern branch (piazza cavour-san ruffillo/rastignano di pianoro) due to space concerns, as articulated trolleybuses are too wide to manoeuvre in piazza cavour.