City elections in Dallas County will coincide with a vote on whether to approve a 1 cent local option sales tax, county supervisors decided Tuesday after receiving a petition with enough signatures to place the issue on the ballot. This is a complicated vote, with the Dallas County residents of Clive, Grimes, Urbandale, Waukee and West Des Moines voting as one bloc because they share borders. For several years, Greater Des Moines communities have attempted with no success to convince the General Assembly to approve legislation that would allow cities with contiguous borders to cast separate votes. Several other Dallas County communities already have the local option sales tax in place. Though the vote is required countywide, it is approved city by city as well as in unincorporated areas of the county. Currently, 93 of the state’s 99 counties have adopted the local option sales tax. Dallas and Polk counties are the local exceptions to the list. In 2015, 10 communities in Warren County voted to adopt the tax. In general, state sales tax dollars are not returned to Iowa cities. It is estimated that Dallas County stands to gain $12.2 million if the measure is approved, based on 2016 tax receipts.