PIERRE, S.D. - Voters in South Dakota's primary on Tuesday will have the option of using new voting machines required by a federal law that was passed to improve the election process.

South Dakota chose to get AutoMARK machines, and each polling place will have one of the touch-screen voting machines, Secretary of State Chris Nelson said.

Each voter will choose whether to fill out a ballot the traditional way, by using a pen or pencil to darken the oval next to that voter's choice, or by using the new machines.

The screens on the AutoMARK machines will guide voters through the process of completing their ballots.

But the machines are designed particularly to help voters with various disabilities fill out their ballots privately without help from others, Nelson said.

People with poor eyesight can increase the size of the type on the screen. Those who are blind can use headphones and have the machine read the ballot to them.

The new machines also will be helpful for those who cannot hold a pen or pencil, Nelson said. They can vote by touching the screen or using a keypad to make their choices, and disabled people who use a device called a switch can plug it into the machine to vote, he said.

"If a voter brings a switch with them, we can plug it into a machine and a voter can manipulate that switch, perhaps with their foot or their mouth or however they are used to operating that switch," the secretary of state said.

"For any voter that's got poor eyesight or one of the disabilities these machines are made for, it's going to make it easier for them to vote," Nelson said.

For some, it will be the first time they have been able to vote with no help from others, he said.

The changes were made because of the Help America Vote Act, passed in 2002 as the result of problems in Florida during the 2000 presidential election. Those changes should help speed up the counting of ballots on Tuesday night after the polls have closed, Nelson said.

Fifteen counties previously counted ballots by hand, but they now will use the same optical- scan ballots that are counted by machines, Nelson said.

Changes required by the federal law cost a total of about $8 million. South Dakota counties had to provide nearly $412,000 as their share, while the federal government provided about $4.6 million to buy the AutoMARK machines and to provide optical-scan machines to counties that previously did not have them. Other federal money will help counties meet the expense of operating the voting machines.