The dangerous free-for-all between cyclists and runners would end along the entire length of Chicago’s 18-mile lakefront bike path — not just along two widened chunks of that trail — thanks to a $12 million donation from hedge fund billionaire Ken Griffin.

Mayor Rahm Emanuel survived Chicago’s first mayoral runoff by fending off critics who contended that his re-election campaign had raked in more than $20 million from the likes of “one-percenters” like Griffin.

Now, the mayor is parlaying his friendship with Griffin in a way that will help all Chicagoans enjoy the city’s lakefront.

Griffin has agreed to donate $12 million to the Chicago Park District to complete the lakefront trail separation project in 2018.

In March, Emanuel announced plans to separate the lakefront trail from Fullerton to Ohio and 31st Street to 51st. It was part of “Building on Burnham,” the mayor’s comprehensive plan to improve Chicago parks and create more open space in a city that needs more of it.

At the time, the plan called for 7 miles of the 18-mile lakefront path to be repaved “with a clear north and south divider” to improve safety.

The Park District will now be able to complete the project and do the same on the 11 remaining miles.

Ken Griffin | Provided photo

Ken Griffin | Provided photo

The project is tailor-made to alleviate congestion on a lakefront trail used by more than 100,000 people each day during summer weekends, according to a recent study by the Chicago Area Runners Association and the Active Transportation Alliance. Emanuel calls it one of the busiest lakefront trails in the nation.

The new and improved trail will be separated into two “distinct paths” for runners and bikers. The bike trail will be 12 feet wide and made of asphalt. It will be located closest to Lake Shore Drive. The pedestrian trail will be 20 feet wide. It will include 14 feet of asphalt buffered by 6 feet of “soft surface mix” on either side.

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Separation of the lakefront trail from 31st Street to the 35th Street Harbor is already “substantially complete.” The resurfacing meets the newly opened 35th Street bridge. Work is currently being completed on the stretch from 35th Street to 41st Street, which will include access to the Burnham Prairie.

The lakefront trail also is being repaved. Roughly 7 miles from Ardmore to Oak Street Beach will be resurfaced. That will remove cracks and add new striping and trail markings.

The project is designed to alleviate areas of congestion by separating the Lakefront Trail into two distinct paths, a biking trail and a pedestrian trail. The entire Lakefront Trail separation project is expected to be complete in 2018. | Provided photo

The project is designed to alleviate areas of congestion by separating the Lakefront Trail into two distinct paths, a biking trail and a pedestrian trail. The entire Lakefront Trail separation project is expected to be complete in 2018. | Provided photo

In a telephone interview with the Chicago Sun-Times, Emanuel said Griffin’s donation will allow Chicago to “do something we’ve been talking about for 20 years.”

“We could not do this without him. These are the investments we should be encouraging. I’m proud he’s doing it in the same way Boeing invests in our cultural attractions,” the mayor said.

“I talked to Ken, who is a biker, and asked him to help us fund this. He’s helping 100,000 people a day. This takes our most important open space and invests in it for the next 50 or 60 years.”

Thanks to Griffin, Emanuel said the lakefront trail will no longer be “like rush hour.” No more will bikers and runners be shouting warnings of “On your left” at each other in hopes of avoiding collisions that sometimes result in injuries, the mayor said.

If people don’t like the fact that the city is relying on a $12 million donation from a billionaire hedge fund investor who has become a poster boy for the so-called one-percenters, Emanuel said, “I’ll take that criticism.”

He noted that separating the lakefront trail from end to end will bolster the Shoreline Protection Project and fulfill Daniel Burnham’s dream of a lakefront free, clear and accessible for public use.

Park District Supt. Mike Kelly said in a press release that he was “grateful for this generous contribution to the improvement of one of our most treasured park amenities.”

“By creating new bicycle and pedestrian paths, more people will have access to use and enjoy the lakefront and its surrounding open spaces,” Kelly was quoted as saying.

Opposition from Friends of the Parks Executive Director Juanita Irizzary killed Emanuel’s plan to give movie mogul George Lucas lakefront land to build an interactive museum. But this time, she’s behind the mayor 100 percent. “Completing the lakefront trail is a great thing. The mayor finds money for the things he cares about. We care about the same thing in this case,” she said.

Friends of the Parks has long pushed for the separation of cyclists and joggers on the lakefront in conjunction with the Active Transportation Alliance and the Chicago Area Runners Association.

When Emanuel announced the first two legs of the lakefront trail separation project, Irizarry called it “the kind of thing we’d be excited about.”

“There have been many safety concerns as pedestrians, runners and cyclists get in each other’s way on a very crowded lakefront. Improving and expanding those trails and separating the different uses from each other is a good thing,” she said then.

During his first term as mayor, Emanuel claims to have added 750 acres of new parkland, 256 new playgrounds and more than $800 million in capital investment from neighborhood and private sources.

The “Building on Burnham” plan also called for: creating a pool and event space at 31st Street Beach Harbor; improving the concert area at Montrose Beach; adding a new triathlon training space at Ohio Street Beach; building a state-of-the-art climbing wall at Steelworkers Park in South Chicago; adding lakefront “gathering places” that would increase access to the Chicago River “at almost every mile” from the Evanston border to Little Village; establishing a goal of increasing protected natural areas from 1,400 to 2,020 acres by 2020.