Article Transportation Research Record 2018, Vol. 2672(7) 58–68 Ó National Academy of Sciences: Transportation Research Board 2018 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/0361198118797215 journals.sagepub.com/home/trr Sensors and the City: Urban Challenges for Parking Occupancy Detection and Pricing Soumya S. Dey 1 , Stephanie Dock 1 , Alek Pochowski 2 , Meredyth Sanders 2 , Benito O. Pe ´rez 1 , Matt Darst 3 , and Eduardo Cardenas Sanchez 4 Abstract Implementing performance parking using demand-driven hourly parking meter rates and real-time occupancy information improves the customer experience and provides more available on-street parking in selected cities across the United States. The implementation of performance parking is not necessarily simple, however, and planners must overcome a host of chal- lenges posed by the urban environment. This paper discusses an approach with the potential to become the state-of-the- practice for developing real-time availability for on-street parking in an urban environment, including how the District Department of Transportation in Washington, D.C., dealt with challenges related to: sensor communication, on-street activ- ity, special events, limited space, broader mobility issues, parking users, coordinating installation, and interagency coordina- tion. Using lessons learned from this project, jurisdictions will be better prepared to deal with their own unique urban challenges, positioning themselves to capture real-time availability and implement performance-based pricing. Since the launch of a performance parking pilot by SFpark in August 2011, theories set forth by the likes of Nobel Laureate William Vickrey and Donald Shoup related to adjusting the cost of on-street parking to estab- lish an equilibrium between pricing and the availability of on-street parking have been at the forefront of manag- ing on-street parking in major U.S. cities. Some cities, like Indianapolis, Cincinnati, and Chicago, used general occupancy trends to set rates in larger ‘‘zones.’’ Others, however, followed San Francisco’s lead, including Los Angeles, New York, Seattle, Boston, and Washington, D.C., exploring the marriage of parking rates to utiliza- tion in a more precise manner. The approach used by the San Francisco Municipal Transportation Authority (SFMTA) to measure histori- cal real-time parking occupancy relied upon the use of in-ground sensors, generally using at least one sensor per space (1). The SFpark initiative, involving 8,200 on-street parking spaces, used 11,917 sensors, 346 repeaters, and 58 gateways, a ratio of 1.45 sensors per space (2, 3). Parking occupancy studies in Los Angeles and Indianapolis had one-to-one sensor-to-space ratios in the study areas. New York City tested using at least two sen- sors per space (placing sensors every 5 to 8 ft), but found that cameras best captured occupancy data when spaces are not demarcated, as discussed below (4). In Washington, D.C., the District Department of Transportation (DDOT) estimated the capital cost to implement every one of the 18,000 metered spaces to be between $2.25 million and $4.8 million, depending on the specific technology. Further, additional annual oper- ating costs could vary between $1 million and $3.2 mil- lion (1). DDOT determined this approach would be unsustainable on a large scale. Cities have attempted other approaches to measure occupancy as well. Since 2011, the New York City Department of Transportation (NYCDOT) has used time-lapse photography-based technology to monitor parking, occupancy, and turnover. NYCDOT found time-lapse technology to be flexible and cost efficient, and it was readily available through off-the-shelf technology. The use of time-lapse photography required a manual review of footage and the help of NYCDOT technicians to install the cameras (5). The City of Seattle conducts an annual parking occupancy data collection effort covering 1 District Department of Transportation, Washington, D.C. 2 Kittelson & Associates, Inc., Washington, D.C. 3 Parking and Mobility Solutions, Conduent, Chicago, IL 4 Parking and Mobility Solutions, Conduent, Austin, TX Corresponding Author: Address correspondence to Soumya S. Dey: soumya.dey@dc.gov