DETROIT -

Polls are open across Michigan as the state begins a shake-up of its 14-member U.S. House delegation and voters decide whether a $500 million business tax cut should proceed.

At least two Republican congressmen face strong primary election challenges Tuesday and voters choose nominees to contest the most open seats since 1992 after four incumbents decided to leave office.

The primary ballot also features scores of legislative races but no contested gubernatorial or U.S. Senate races. Voters will set the stage for November elections that could decide control of the state House of Representatives.

The lone statewide ballot measure in Michigan is Proposal 1. It asks voters to endorse a cut in taxes paid on business equipment.

Primaries set stage for state Legislature election

Two Republican congressmen faced strong challenges Tuesday in Michigan's primary election while voters also chose nominees in four open seats, the biggest shake-up in the state's U.S. House delegation since 1992.

The ballot had scores of legislative races but no showdowns in races for governor and U.S. Senate. Republican Gov. Rick Snyder will face Democratic challenger Mark Schauer in November, while the GOP's Terri Lynn Land will square off against U.S. Rep. Gary Peters for a Senate seat in the fall.

Closely watched House races included business-backed challenges to conservative congressmen on opposite sides of Michigan. Rep. Justin Amash in the Grand Rapids area faced a threat from investment adviser Brian Ellis. Rep. Kerry Bentivolio went up against lawyer Dave Trott in suburban Detroit. Both challengers gave or loaned their campaigns at least $3.4 million.

"I live in his district and never see him," said Ralph Martin, 76, of Livonia, who walked quickly through morning rain to vote for Trott over Bentivolio. "I couldn't even form an opinion of him. He hasn't done much in Washington."

Bentivolio, a former teacher and reindeer farmer, was elected in 2012 after a Republican incumbent was knocked off the ballot due to fraudulent petition signatures.

"It was a fluke," Martin said.

But Steve Hall, 59, of Livonia said he voted for Bentivolio partly because he's "down to earth, a regular kind of guy."

Voters also began the process of filling four seats that incumbents will leave at year's end.

Rep. John Dingell, a Dearborn Democrat who has been in Congress for a record 58 years, will retire along with Republicans Reps. Dave Camp of Midland and Mike Rogers of Howell. A fourth House seat is opening up because Peters of Bloomfield Township is running for the Senate seat held by retiring Democrat Carl Levin.

Primary winners from the departing congressmen's party will have the edge come November.

It is the most open seats since 1992, when redistricting, retirements and a primary upset ushered out seven of 18 House members.

Republican Reps. Fred Upton and Tim Walberg in southern Michigan also have primary challengers. So do GOP Rep. Dan Benishek in northern Michigan and longtime Democratic Rep. John Conyers of Detroit. With a win in his Democratic-heavy district, Conyers will be well on his way to succeeding Dingell as the current longest-serving member of the House.

And Dingell's wife, Debbie, is expected to extend the Dingell dynasty beyond its 81-year run since she faces nominal opposition in his Democratic seat between Ann Arbor and the "Downriver" working-class Detroit suburbs. Before John Dingell held the seat, his father John Dingell Sr. represented the district for 22½ years.

Rain, thunderstorms in forecast for Election Day

Voters in parts of Michigan may be greeted by rain and thunderstorms as they go to the polls.

The National Weather Service says stormy weather is in the forecast for Tuesday in places, with hail and gusty winds a possibility.

The storms come a day after neighborhoods in the Detroit suburb of St. Clair Shores flooded amid thunderstorms that brought heavy rain and hail. Authorities closed some area streets after motorists got stranded. Some used kayaks to get around.

Officials say streets and yards flooded after St. Clair Shores' sewers were unable to drain all of the water. Parts of the Grosse Pointe communities also were affected.

The weather service says more than an inch of rain fell in less than an hour. Some street flooding lingered on Tuesday morning.