Washington area voters had some of the longest wait times in the nation — averaging more than a half-hour in the District — at the polls on Election Day 2012, according to a report measuring election administration across the country.

The report, published Tuesday by the Pew Charitable Trust’s State and Consumer Initiatives program, found a marked improvement across the country in election administration from 2008 to 2012. Many states embraced new technology, the report says, eliminating errors, improving verification and voter registration and allowing voters with disabilities or illnesses and those serving overseas in the military to cast ballots with more reliability.

“This is a bipartisan mix of states. This is not something that only Republicans or Democrats have license to,” said David Becker, Pew’s director of election initiatives. “It’s really a technological reform-based mind-set.”

The study, which measured 17 indicators, found a sharp increase in the number of states that offer online voter registration, conduct post-election audits and provide a transparent look at the data they collect.

The District of Columbia measured near the bottom of most categories in 2008. But D.C. officials improved the voting experience in recent years, and the District climbed the national rankings more than any of the states from 2008 to 2012, when it was ranked 40th.

The number of voters in Washington who had problems casting ballots because of disability or illness dropped 1.2 percent between the two presidential elections. The number of mail-in ballots rejected by election officials dropped nearly 1 percent. And the percentage of ballots successfully returned by military and overseas voters jumped 35 percent.

A higher percentage of people eligible to vote, 92 percent, are registered in Washington than in any state in the country.

Still, D.C. election officials issued a large number of provisional ballots on Election Day 2012, an indication of potential problems with the voter-registration system. Provisional ballots are cast when a voter shows up at the wrong precinct or doesn’t appear in a poll book. The ballots are kept out of the final count until the voters’ identities and eligibility can be established.

District residents also had to wait in line for an average of 34 minutes to cast a ballot. Only Florida voters, at nearly 45 minutes, had a longer average wait. District officials said in a post-election audit that greater reliance on provisional ballots, which take longer to process, was to blame for the long waits. The District’s Board of Elections also delayed reporting results for six hours in 2010.

Despite the improvement, election administration remains a challenge for District officials, highlighted by slow vote-counting in the April 1 primary elections. Delays were blamed on improper operation of new electronic voting machines that didn’t produce accurate counts. Once election officials noticed problems with five machines, they stopped releasing electronic results and visited precincts to retrieve accurate counts.

Maryland placed seventh in Pew’s overall rankings of the 50 states and the District, bolstered by very low rates of rejected registration applications and a higher rate of provisional ballots accepted by election officials.

But Maryland voters waited an average of 29 minutes to cast a ballot in 2012, five minutes longer than the average in 2008. The state also saw an increase in the number of military and overseas ballots that went unreturned.

On the other hand, Virginia, which ranked 19th nationally, dramatically increased the percentage of overseas ballots it accepted. In 2008, the commonwealth rejected nearly 8 percent of those ballots, and almost 30 percent of overseas ballots weren’t returned on time. In 2012, the state rejected just 1.7 percent of overseas ballots, and all but 17 percent were returned.

The improvement came after Virginia’s legislature passed the Uniform Military and Overseas Voters Act in 2011. The law streamlined voting procedures and upgraded the process by which those voters cast their ballots.

Virginia was among those states where voters with disabilities or illnesses were most likely to have problems casting a ballot, the report says. And while the commonwealth cut the average time voters waited in line from almost 29 minutes in 2008 to almost 24 minutes in 2012, the average wait was still the fifth-longest in the nation.

States that performed best across the varied criteria included North Dakota, which has ranked at the top of all three Pew Elections Performance Index reports. Minnesota, Wisconsin and Colorado all scored high marks.

Mississippi finished at the bottom of the list. Voters there had to wait longer than the national average, turned out at lower rates and had no way to register online. The state submitted far less data on the number of absentee ballots rejected or the number of military and overseas voters whose ballots didn’t count.

Virginia, Maryland and the District were all among the 18 jurisdictions that submitted a complete roster of 18 core statistics to the U.S. Election Assistance Commission’s Election Administration and Voting Survey in 2012, up from just seven states in 2008.