“Marin, with just 217,000 people of driving age, has over 750,000 parking spaces,” the pair add. “These 4,000 acres of parking are equivalent to the combined area of China Camp State Park, Angel Island, Muir Woods National Monument, Camp Tamarancho and Ring Mountain Preserve. Paved surfaces increase stormwater runoff and amplify high temperatures, an increasing concern given more frequent and intense heat waves.”

“Marin doesn’t need all of this parking,” write Silva and Wells. “Towns have wildly different policies, based more on accidents of history than sound analysis. For multi-family housing, Mill Valley requires 25% more parking than Tiburon, and Fairfax requires 32% more than San Anselmo. These dramatic differences wouldn’t occur if parking mandates were scientifically based. Excess parking consumes too much land. We require almost as much space for cars as we do for tenants. If even a quarter of our parking lots went to more apartments, it would go a long way toward solving our housing crisis.”

“Parking is expensive,” they write. “Many Marin households have fewer than two people. Not everyone drives. Yet, mandates often require two or more parking spaces per household. That’s not cheap. A recent report estimates that each parking space costs between $35,000 and $90,000 per unit, or approximately $300 per month more in rent. Two off-street spots increase rent by $600 per month. Parking also encourages people to drive more, contributing to traffic and emissions. A UC Santa Cruz study found that people, including car owners, who lived in buildings with off-street parking drive more than those without it. Just parking further away encourages people to walk, bike or use transit more.”