CHICAGO (CBS) — Chicago billionaire Ken Griffin has donated $12 million to the Chicago Park District to make the Lakefront Trail safer by creating separate paths for joggers and cyclists along all 18 miles of the trail.

“I am a runner, I am a biker, and I will be clear: the vision of separating the runners and bikers on the lakefront is a vision I’m 100 percent behind,” Griffin said as he stood with Mayor Rahm Emanuel at the announcement in Bronzeville. “I’m pleased and proud to support making our lakefront better and safer for all who take so much pleasure and joy in this great crown jewel of our city.”

The mayor said the seed for the idea of separate lanes for cyclists and pedestrians was planted when he had lunch with Griffin around the time a woman was seriously injured in a collision on the trail.

“She looked one way – she was going for a run – and got hit by a biker; was in the hospital emergency room,” Emanuel said.

Active Transportation Alliance executive director Ron Burke and Chicago Area Runners Association executive director Kevin Jermyn said the new trail will be a lot safer.

“From a runner’s perspective, this is an absolute game-changer,” Jermyn said.

Burke said, on a busy summer weekend, more than 100,000 people use the trail.

“Anyone who’s ever used the Lakefront Trail knows … you have walkers, and runners, and cyclists, and people with strollers, and that’s a recipe for crashes to happen,” he said.

Earlier this year, the city had already begun work to create separate lanes for cyclists and joggers between Fullerton Avenue and Ohio Street on the North Side, and between 31st streets and 51st streets on the South Side. Griffin’s donation will allow the city to create separate paths on the remaining 11 miles of the trail.

The bike trail will be 12 feet wide, and will be located closer to Lake Shore Drive, according to the mayor’s office. The pedestrian trail will be closer to the lake, and will be 20 feet wide; including 14 feet of asphalt with 3 feet of soft surface mix on both sides.

The mayor’s office said the work to create separate paths from 31st Street to 51st Street is almost done, and will match the pavement on the new 35th Street bridge over Lake Shore Drive.

The project is expected to be completed in 2018.