Paper tickets are nearing the end of the line on AC Transit buses.

On Saturday, AC Transit will stop accepting paper tickets as payment to board buses, and the agency is urging riders to use unused tickets by Friday.

Riders can also apply any remaining value of their paper tickets to the new Clipper smart cards. The reloadable Clipper cards are good for use on several Bay Area transit systems, including BART, and are available free of charge for a short introductory time. Customers add fare value to the card by paying in cash or linking it to a bank account or credit card.

For information about acquiring the Clipper card, go to www.actransit.org/ and click on "Clipper," or call 877-878-8883. Clipper cards can be ordered online or obtained at AC Transit's Oakland headquarters at 1600 Franklin St. and at several retail stores listed on the bus system's website.

Information about exchanging paper tickets for Clipper cards is also available on AC Transit's website or by calling its ticket office at 510-891-4706 on weekdays.