A Detroit billboard campaign admonishing state legislators for the high cost of auto insurance in Michigan has morphed into an advertising vehicle to aid legislative candidates backed by Detroit Mayor Mike Duggan.

Detroiters for Change, a nonprofit group that doesn't have to disclose its donors, recently changed its "Thanks, Lansing!" billboards highlighting disparities in insurance premiums and medical payments to advocate for three Duggan-endorsed candidates in the Aug. 7 primary.

Billboards on the east side recently changed to say, "We need Adam Hollier in Lansing," and billboards on the west side of the city now advocate for Marshall Bullock, a district director for Duggan. Billboards in the 6th House District that includes downtown and riverfront areas advocate for Terra DeFoe, who works for the mayor in senior citizen outreach and faith-based initiatives.

"This is a way to get the mayor's candidates elected … and attack those who did not support him," said state Rep. Fred Durhal III, who helped defeat Duggan's auto insurance reform legislation last fall. Durhal is running against Bullock in the 4th Senate District.

In Detroit, the billboard campaign that started in May by decrying the wide gulfs between the cost of medical procedures under Medicare and what auto insurers shell out has elevated an issue that has been festering in the Legislature for years.

After multiple legislative setbacks in Lansing, Duggan is backing Democratic candidates in about a dozen House and Senate primaries in Wayne County this summer who could play a pivotal role in delivering the mayor's long-sought auto insurance reforms.

Michigan's highest-in-the-nation auto insurance premiums have become a marquee issue in political campaigns this year, with politicians of all stripes promising different reform measures to cut rates.

Just this week, Attorney General Bill Schuette launched the first TV ad of the gubernatorial election that focuses entirely on reining in high auto insurance premiums.

"This message has to be clearly sent up the highway to Lansing that this is something we need to really seriously look at and pass," said Mario Morrow, a Detroit political consultant running the Detroiters for Change campaign.

Detroiters for Change is advocating for "driver's choice" auto insurance reform measures that would allow motorists to purchase lower levels of medical care in exchange for guaranteed rate reductions. Duggan lobbied legislators for a similar plan last fall before it failed in the House.

Morrow said the group is not working directly with Duggan or his office on the campaign and it's "just a coincidence" they're backing the same candidates Duggan favors.

Duggan was out of town Tuesday and unavailable for comment, a spokesman said.

Dave Massaron, chief operating officer for the Duggan administration, said Tuesday the second-term mayor is supporting candidates "who back driver's choice" for auto insurance reform.

"He's glad to see all the other groups that are also backing driver's choice candidates," Massaron said in a statement. "Maybe we'll finally get Michigan car insurance rates down."

Detroiters for Change, formerly called Reform Auto No-Fault Now, is incorporated under section 501(c)4 of the Internal Revenue Service code, which allows the organization to circumvent campaign finance disclosure laws and keep its donors secret.

Morrow declined to reveal the donors paying for the billboard, but described them as a "melting pot" of businesses and individuals "who are really, really concerned about auto insurance and the cost of it."

"I'm not in a habit of giving out names and addresses of individuals who support causes," he said "People are very sensitive about disclosure, especially with this being a strong political environment."

The advertising message that "we need" a particular candidate in Lansing blurs the law restricting a nonprofit 501(c)4 organization from spending more than half of its money advocating for the election of a certain candidate, Craig Mauger, executive director of the Michigan Campaign Finance Network,

"Most people would come to the conclusion that this billboard is telling me to send this person to Lansing," Mauger said. "If that's not express advocacy, we're going to start seeing a lot of commercials saying 'we need Gretchen Whitmer in Lansing' or 'we need Bill Schuette in Lansing.' "