If just 6 percent of downtown workers ditch their cars for a proposed free bus pass, commuting patterns indicate that could free enough parking spots to attract new employers who’d bring downtown offices near full occupancy.

Nearly two-thirds of downtown property owners voted in favor of paying 3 cents per square foot of retail and office space toward buying discounted bus passes in bulk for the estimated 43,000 private-sector employees in the Capital Crossroads Special Improvement District starting…