Hikers who want to hit the trails of the San Gabriel Mountains without getting in the car can take a free shuttle from the Duarte Gold Line station to the trailhead of Fish Canyon Falls.
The service runs through the end of June on Saturdays 7 a.m. to 6 p.m.
The 4.8-mile out-and-back hike winds through an active rock quarry to Fish Canyon Creek, ending at a three-tiered waterfall.
Getting better public transit access to nature areas like Fish Canyon has been a focus for advocacy groups like The City Project, which runs a program called Transit to Trails.
"Low-income communities and communities of color disproportionately lack access to green space, and transportation remains a significant barrier for many families to reach existing natural resources," according to Robert Garcia, the group's director.
It's a concern President Obama addressed when he declared the San Gabriel Mountains a national monument in 2014.
"This is an issue of social justice," said Obama. "It's not enough to have this awesome natural wonder within your sight. You have to be able to access it."
The president's action gives the nature area protected status and could make more federal resources available for improvements like trail maintenance and better park access.
Conservationists with the group San Gabriel Mountains Forever hope the designation will further improve transit links to the trailheads, not only to give expanded access to those without a car but to mitigate some of the environmental impacts of crowding at the sensitive sites.
"They're just packed to the gills with vehicles," said Belinda Faustinos, strategic adviser to the group. "There is just too much vehicular traffic."
Faustinos and her group hope Congress will provide funding to improve transit links to the national monument from low-income areas. She's working with other cities around the Gold Line to implement shuttle services similar to the one in Duarte.
"We're tremendously excited about the Gold Line and the new opportunities it presents for getting closer to nature," she said.