DETROIT – A $4 million roadway project beginning in early July will benefit drivers in the 2015 Verizon IndyCar Series race weekend on Belle Isle.

Much of the asphalt on the 2.36-mile course will be replaced by concrete, and the kink between Turns 6 and 7 will be removed to create a second long straight. The only asphalt section will be the short straightaway in front of pit lane through Turn 1 to entry of Turn 2.

Event chairman Bud Denker said the largely Penske Corporation-funded plan was set in motion when Chevrolet extended its entitlement sponsorship through 2016. He confirmed that a Verizon IndyCar Series doubleheader would return in 2015.

“To invest like we’ll be investing, you have to have a plan,” Denker said. “We needed a multi-year agreement to go forward. That two-year commitment gave us the ability to make that investment.”

Denker estimated more than 100,000 spectators for the three-day event following the second round of the Chevrolet Indy Dual I Detroit presented by Quicken Loans. With glorious weather, he said walk-up sales were brisk and sponsor chalets were sold out.

The 982-acre site became a state park in February, and Michigan Gov. Rick Snyder and General Motors CEO Mary Barra were among the guests June 1 to take part in the grand re-opening of the island as the backdrop for the 70-lap races telecast on ABC.

“I thought it was a pretty damn good weekend,” he said. “I mean, did this city shine, or what? I was telling some of our people, if you dropped somebody on to Belle Isle today blindfolded and said, ‘Where are we?’ — and then you took ’em out back and saw the boats that were anchored out there and the glistening of our island — you wouldn’t know if it was San Diego or Monaco or Detroit. It was unbelievable.”