California communities now have a tool to help them design and site buildings that promote less driving, lower greenhouse gas emissions, and greater affordability. GreenTRIP Connect, conceptualized by TransForm and developed by CNT, quantifies how much space and resources can be saved by using GreenTRIP strategies like building near transit, right-sized parking, transit passes, and access to car and bike share.

GreenTRIP Connect lets users enter the location of a parcel and a variety of inputs – like the number of units in the building, whether any of those units will be affordable, and number of parking spaces – and in return, the tool estimates the parking usage, average number of miles driven per day, and average daily greenhouse gas emissions. It also provides the dollar value of access to alternative transportation choices for residents. CNT’s research and analytics, led by Peter Haas, Chief Research Scientist, drives the calculations behind the tool.

It’s easy to take parking as an inevitable necessity in any city, but overbuilt parking can wreak havoc on an urban environment. Parking takes up space that could be better used for housing or retail, and it is extremely expensive to build. The average parking space – as in each individual stall – requires, on average, $20,000 to $80,000 in construction costs. With the housing crunch in California, especially in the Bay Area, this money and space could be much better spent on housing people.

Making the problem worse, residential parking is actually often underused despite the perceived scarcity of parking in most American cities. For the 68 buildings in the GreenTRIP Parking Database, released in 2014, the average percentage of vacant spaces per building was 31%. For some buildings, it was as high as 69%. We need smarter parking decisions and policies, and GreenTRIP Connect shows what a difference better parking choices can make.

Luckily, the national conversation on parking is starting to shift. GreenTRIP Connect is part of a growing suite of parking tools and reports that we’ve created over the past few years for cities across the country, from Seattle to D.C. to Chicago.