The Commuter is a role that "leaves Town" each Night, thus making them ineligible to be targeted by Night actions. By extension, they cannot use any other Night actions they may have.
Because they cannot use Night actions, almost all Commuters are pro-Town.
It is worth noting that because in flavor it physically leaves the game for the Night instead of being protected somewhere in Town, Commuter is considered the ultimate in Untargetability, trumping even things like Strongman.
A Commuter is considered Normal on mafiascum.net. If a Commuter is commuting, it is untargettable that night by any means, not even Strongman, Roleblocker or Ninja. Any role that attempts to target a commuting Commuter should be treated as though they are blocked (e.g. receive a "No Result" pm if they are investigative).
Use and Power
Commuter blends all the strongest aspects of Bulletproof and Ascetic. It is futile to target them at all while they commute. However, the only roles that may be helpful if they targeted the Commuter are investigative, so in all other cases, Commuter is strong and difficult to use improperly.
Commuter is not an implausible scum fakeclaim, as it explains immunity to kills and (occasionally) blocked actions. If you are an X-Shot Commuter, keep this in mind.