The benefits of time away from tailpipes extend to the cellular level. Traffic pollution ravages the wet, vulnerable interior of plant leaves, reducing their growth and making them less resilient in the face of other environmental stresses. Our lungs are not so different, relying for their function on openness to air. When we exercise in a polluted atmosphere, like the runners and cyclists who until now panted alongside cars on Central Park’s drives below 72nd Street on weekdays, the negative effect is magnified: We draw more ozone, carbon monoxide, nitrous oxide, particulates and petroleum hydrocarbons into contact with our cells.

Keeping traffic away from places where people exert themselves therefore yields health benefits beyond reduced vehicular collisions. We leave the park with healthier lungs and blood.

The car ban delivers benefits even though parks are embedded in a traffic-filled city. Sound intensity and air pollution drop roughly exponentially with distance. The loop-drive closing increases the space between car engine and living body from arm’s length to dozens or hundreds of yards. In addition, trees in parks actively clean particles of pollution from the air and absorb sound. The negative effects of surrounding streets and the remaining park roads — transverses in Central Park and Flatbush Avenue in Prospect Park — are reduced by barriers of walls, trees and partly sunken road beds.

These combined social and physiological effects of parks manifest in well-being: Living closer to green space and away from traffic is associated with better bodily and societal health for people and with higher biodiversity.

A car-free park also opens the imagination. The petroleum-driven automobile is an evolutionary novelty, barely 150 years old. Human and nonhuman bodies are ill adapted to this newcomer. Yet we’ve remade the world to accommodate these machines and we seldom escape their presence. To spend a little time away from our wheeled, combustive technologies is to nourish our imaginations, giving us a lived experience of a world not dominated by the automobile.

A century ago, New York City showrooms were among the first to feed the popular imagination with dreams of automobiles. Now, the city’s parks offer a vision of a future where we orient the city around living communities.

After you’ve tasted the refreshed air of Central Park and enjoyed its sylvan sounds, wander over to the Lake. A vigorous dip of your rowboat oars will stir a hidden record of ecological interconnection within the city. The deepest layers of submerged lake mud date from the 19th century and contain the chemical signature of burned wood, a record of the city’s dependence on trees for fuel.

Higher in the mud layer, coal remnants dominate the strata deposited in the first half of the 20th century, a chemical memory of the smokestacks that surrounded the park. In those days in the city, every tree leaf and human lung also bore the stain of smoke. Lake sediments from the past half-century are marked with the chemical residues of burned petroleum, as are our bodies and communities. What record will the coming decades scribe into the mud? A car ban in city parks allows us to imagine a more healthful legacy.