System and Method for Conditionally Releasing a Parking Brake of a Trailer

A method comprising:

• performing in a vehicle comprising a tractor and a trailer:
• determining whether a parking brake of the tractor is engaged;
• determining whether an air compressor of the tractor is running;
• determining that a service brake was pressed and that a request was received to disengage a parking brake of the trailer;
• and
• causing the parking brake of the trailer to be disengaged in response to determining both that the parking brake of the tractor is engaged and that the air compressor of the tractor is running.

A system comprising:

• means for determining whether a tractor is parked;
• means for determining whether an engine of the tractor is running;
• and
• means for causing a trailer coupled with the tractor to be un-parked in response to determining both that the tractor is parked and that the engine of the tractor is running.