Metropolitan Area Planning Council is a regional planning agency promoting smart growth and regional collaboration for the Metro Boston area.
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Building too much parking has
real consequences, including:
Increasing housing costs
Decreasing transit ridership
And there are costs to building too much parking
More Parking = More Cars = More Traffic
10 parking spaces could cost
$160,000 in unnecessary construction
1: Blended rate determined by average construction cost for surface and garage spaces and based on proportion of surface (42%) and garage (58%) spaces observed during overnight counts. We estimated an average construction cost of $23,500 per garage space based on WGI’s Parking Structure Cost Outlook for 2018, which assumes all above-grade construction, and a below-average rate of $6,000 per surface space.
In other words, how do we find the perfect fit to align parking supply and demand?
I don't want to pay for parking I no longer use.
I'm looking for a place with parking for two cars.
I wouldn't drive if I had another option.
I am looking for a place with bike parking.
when it comes to residential parking.
I need a vehicle for trips to the grocery store.
I kept my car because finding parking is easy.
how much parking is actually being used?
In coordination with property owners, MAPC collected overnight parking data at nearly 200 sites across the Inner Core.
Based on our data, the average
50 parking spaces.
would be unoccupied.
Parking Demand per Unit:
Parking Supply per Unit:
total housing units
unoccupied housing unit
the total number of parking spaces divided by the total number of housing units.
the number of occupied parking spaces divided by the number of occupied housing units.
the number of occupied parking spaces divided by the total number of parking spaces.
Average parking supply
Average parking demand
We observed excess parking in all communities surveyed
What factors drive
We investigated 25 factors for their potential influence on parking demand
• Percentage of units that are affordable
• Year of construction
• Average bedroom count
• Average rent or purchase price
• Number of units in building
• Housing tenure
• Presence of bicycle parking
• Parking cost
• Ratio of parking cost to monthly rent cost per bedroom
• Ratio of parking cost to monthly rent cost per unit
• Percent of provided parking spaces that are garaged
• Ratio of garage to surface parking spaces
• Parking supply
• Number of jobs accessible by 30-minute transit trip
• Neighborhood population density
• Neighborhood employment density
• Neighborhood population and employment density (cumulative)
• Presence of MBTA commuter rail station within half-mile
• Presence of MBTA rapid transit station within half-mile
• Median annual income (Census tract)
• Average household size for rental households (Census tract)
• Average household size for ownership households
• Share of households in U.S. Census tract that are renter-occupied
• Share of households in U.S. Census tract with zero vehicle
These are just some of the factors that individually drive parking demand up or down
Number of Transit
Demand per unit
Parking Supply per Unit
Percentage of Affordable Units
While the number of jobs accessible by transit and the share of affordable units in a building influence parking demand...
...parking supply was found to be the primary driver of parking demand.
The more jobs accessible by transit, the lower demand for parking.
The larger the share of affordable units in a building, the lower demand for parking.
The more parking spaces supplied per unit, in a building the higher the demand for parking.
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Our statistical modeling revealed three factors to be strongly associated with parking demand.
Number of Jobs Accessible by Transit
Cumulative employment accessible from Census block in a 30-minute transit trip, University of Minnesota Accessibility Observatory
Percentage of Affordable Units
Parking Supply Per Unit
Supply per Unit is the # spaces divided by number of units
1) Require fewer spaces – or none at all.
Cities and towns can reduce existing requirements, tailoring them to different types of developments in different locations. In some cases, parking minimums can be eliminated entirely.
2) Design transit-oriented developments for transit-oriented households.
Abundant parking at developments meant to be transit-oriented is counter-productive. New housing in areas with good transit should provide less than one space per unit to accommodate households with fewer vehicles.
3) Don't make people pay for what they don't need.
Property owners should unbundle the rental cost for housing and parking so that residents can choose whether to rent a parking space. State and local regulators should encourage or require such unbundling.
4) Less parking, more affordable housing.
Because residents at affordable housing sites are demonstrated to have lower parking demand (and thus are more dependent on transit), we should not only build less parking at transit-oriented sites, but those sites should have a larger share of affordable units.
5) Get ready for a parking marketplace.
Increased pressure on street parking combined with excess parking at residential developments sets the stage for an app-enabled parking rental marketplace. Public agencies should set parameters and tax policy now, before this market has established itself and becomes resistant to regulation.
Read more about Transporation Demand Management strategies you can advocate for in your community.
Find the full report and technical appendix here.
If you have questions or comments, don’t hesitate to reach out!
Improving the Way Developers and Planners Assess Parking Demand