County residents could soon be choosing candidates for public office the same way they buy groceries.

Fairfax election officials are moving to replace the 14-year-old push-button voting machines with video touch-screen monitors. County voters at six polling places in Vienna and Reston will have the first chance to experiment with the technology when they vote Tuesday.

Touch screens are more and more common in our daily lives. By tapping images on a screen, we can check out groceries, find CDs and books, pay parking tickets and pull cash out of an ATM. Now, the county is testing two touch-screen voting systems that work the same way.

Out of the feedback from the Vienna and Reston voters, county election officials said they hope to make a final recommendation to the Board of Supervisors on which of two touch-screen systems to buy. The tab would be about $5 million, officials said, for about 1,250 machines at 219 polling locations.

Margaret K. Luca, secretary of the county elections board, said officials want to buy the touch-screen machines by the end of this year so voters could use them for the November 2003 elections, when county supervisors, state senators and delegates are on the ballot.

Though the current push-button system is reliable, replacement parts are no longer manufactured and the machines have become expensive to maintain. Their relatively large size also requires significant storage space, Luca said.

The new machines, about the size of a briefcase, use state-of-the-art electronics that help make them more portable, accessible to people with disabilities and cheaper to maintain than the current system.

Audio headsets enable visually impaired people to cast their ballots, officials said, and the size and 10-pound weight of the machines make them easy to move.

The machines can transmit election returns in a matter of seconds via modem, officials said, resulting in faster election results. The touch-screen machines also have several built-in safeguards to protect against election fraud.

The two touch-screen systems under consideration -- Advanced Voting Solutions' "WINvote" and Election Systems and Software's "iVotronic" -- will be tested Tuesday.

Voters at the Dogwood, Hunters Woods and Glade polling locations in Reston will use the WINvote system, while the iVotronic machines will be used by voters at Vienna Precincts 1, 2 and 4.

William Ludwick shows Tom McLean, with daughter Kelly, a voting machine.