Prospect Park is officially car-free forever, but huge portions of Central Park remain open to motorists. Tomorrow, volunteers with Transportation Alternatives will kick off a campaign to get the cars out of Central Park in 2018.

The event starts with a rally near Tavern on the Green at 11 a.m. Afterward, you can brave the cold on your bike for four laps along the loop below 72nd Street, where cars are still allowed during some weekday hours.

A car-free Central Park is a popular cause, and advocates have made a lot of progress, but the job’s not done yet.

DOT and the Parks Department barred motorists from driving in the park north of 72nd Street in 2015. Below 72nd Street, car traffic still roars on the West Drive and Terrace Drive on weekdays from 8 a.m. to 10 a.m. The Center/East Drive between 6th Avenue and Park South and East 72nd Street is a motor vehicle shortcut on weekdays from 7 a.m. to 7 p.m.

The de Blasio administration remains reluctant to make those remaining segments car-free. “There are a lot of challenges in doing that,” DOT Commissioner Polly Trottenberg told reporters on Tuesday. “All that’s really left in Central Park is basically the southeastern corridor, which is also the most congested part of the park, so we’re still looking into that.”

You can RSVP for tomorrow’s rally on TransAlt’s website.