Transportation Demand Management (TDM) and Parking

Transportation demand management (TDM) is a set of strategies and policies that reduce drive-alone trips by encouraging alternatives such as transit, biking, walking, carpooling and working from home.

Transportation demand management is the toolkit, transit passes, carpool matching, bike facilities, flexible schedules, priced parking, that moves trips off the drive-alone stack. Fewer solo drivers means less parking to build. Illustrative mode shares.

For parking, TDM is the other side of supply. Every commuter who switches to transit or a carpool is a space that does not need to be built or leased. Many cities now require TDM plans for new development, and some reduce parking requirements in exchange.

Common TDM strategies

Parking pricing. Charging for parking, and unbundling it from rent, is among the most effective measures.
Parking cash-out. Offering employees cash instead of a free parking space.
Transit benefits. Subsidized passes and pre-tax transit accounts.
Bike and walk support. Secure bike parking, showers and safe routes. See micromobility.
Ridesharing. Carpool matching and preferential carpool parking.
Flexible work. Remote work and flexible schedules that flatten peaks.

Measuring results

Track mode share and parking occupancy before and after implementation. TDM plans that are monitored and adjusted perform far better than those filed and forgotten.

The Parkonomics view

TDM is the cheapest parking space a project will ever add. Pricing is the strategy that makes the others work.