The Christian Democrats promised to give the state’s two seats on the carmaker’s 20-person supervisory board to business experts rather than politicians, as has been the case. Critics contend that weak oversight by the supervisory board helped create an environment where wrongdoing could fester.
The company’s problems are a serious threat to the economy in Lower Saxony. Volkswagen has its headquarters and flagship factory in the city of Wolfsburg, near the state’s eastern border. About 120,000 people work for Volkswagen in Lower Saxony, plus tens of thousands more at suppliers and service providers that depend on the company.
But the company’s ability to invest in new technologies has been handicapped by $26 billion in fines and court settlements stemming from its admission that it had evaded emissions limits in the United States.
Stephan Weil, who as state prime minister sits on Volkswagen’s supervisory board, faced criticism that he was a weak overseer who had only learned about the emissions scandal from the news media and allowed the company to vet a speech he gave about the crisis.
Mr. Weil, a former mayor of Hanover who recently told a German radio station that he likes to listen to Bruce Springsteen while ironing his shirts, trailed badly in polls last summer but regained support in the final weeks of the campaign.
“People are obviously satisfied with us,” Mr. Weil told broadcaster NDR.
The Social Democrats led by Mr. Weil won 37.3 percent of the vote, a gain of almost 5 percentage points from elections in 2013, according to unofficial returns. The result was a significant boost for the Social Democrats, who have steadily lost support at the national level. It was unclear whether Mr. Weil would be able to preserve his governing coalition with the Greens, who won 8.9 percent, according to the early results.
The Christian Democrats were not far behind the Social Democrats at 33.4 percent, and still stood a chance of winning the official tally.
Radical parties on the right and left, which have drained support from mainstream parties at the national level, did poorly in Lower Saxony on Sunday.
The far-right Alternative for Germany, known by its German initials AfD, won 6.2 percent of the vote, according to the early returns. That would be barely enough to seat a delegation in the state Parliament, and well below the result in national elections last month. The showing is likely to be seen as a setback for the AfD.
The Left party, which has roots in the Communist Party that once controlled East Germany, apparently did not achieve the 5 percent share of votes needed to secure a place in the state Parliament.
The Christian Democrats in Lower Saxony began the election campaign with a substantial lead but may have been hurt by Ms. Merkel’s performance in the national elections last month. Though Ms. Merkel’s party retained power in Berlin, its showing was the worst in decades. The chancellor is now trying to form a government with two smaller parties despite big differences in their views. Her negotiating clout could be weakened by Sunday’s result.
The insular nature of Volkswagen’s supervisory board, which is dominated by state politicians, labor leaders and representatives of the Porsche family, is often seen as a factor in the emissions crisis.
Volkswagen has pleaded guilty to charges in the United States that it used illegal software to cloak excess emissions in 600,000 diesel cars.
Lower Saxony’s Christian Democrats, led by Bernd Althusmann, promised to take a more professional approach to Volkswagen, creating a dedicated staff in the prime minister’s office that would help manage the state’s stake and provide better oversight.
But none of the parties has called for more radical steps, like selling the state’s shares in the company or giving up the state’s right — enshrined in a special “Volkswagen law” — to veto plant closings. Those privileges are viewed as sacred in Lower Saxony — a bulwark against predatory investors who would put profits ahead of job creation.