Touchscreen Voting Machines Cause Long Lines and Disenfranchise Voters
  Computerized touchscreen "Direct Recording Electronic" DRE voting systems have been used by over 1/3 of American voters in recent elections. In many places, insufficient DRE numbers in combination with lengthy ballots and high voter traffic have caused long lines and disenfranchised voters who left without voting. We have applied computer queuing simulation to the voting process and conclude that far more DREs, at great expense, would be needed to keep waiting times low. Alternatively, paper ballot-optical scan systems can be easily and economically scaled to prevent long lines and meet unexpected contingencies. 
William A. Edelstein and Arthur D. Edelstein