Embodiments of systems, methods, and devices are disclosed for enabling wireless mobile devices to be automatically detected and used as fare media on vehicles in a transit and/or transportation system. Embodiments include detecting a wireless mobile device and utilizing a unique identifier of the wireless mobile device to track a transit user's entry to and exit from a transit vehicle. Embodiments further include causing the wireless mobile device to display a fare payment indicator, allowing the transit user to use the wireless mobile device to show proof of payment if so solicited by a fare inspector. A corresponding fare can be calculated and paid for in a variety of ways.