Estimating parking lot footprints in the Upper Great Lakes Region of the USA

The primary objective of this paper is to quantify the areal footprint of parking lots across a four state region including Illinois, Indiana, Michigan and Wisconsin located in the Upper Great Lakes Basin. Parking lots are virtually everywhere in urban and suburban environments, are often larger than the building footprints they serve yet they are largely unregulated on a regional scale. We focus on a method that estimates parking lot coverage over the four state region and use independent studies to estimate model parameters and validate our model.In total, we estimate that the states of Illinois, Indiana, Michigan and Wisconsin allocate 1260 km2 of their land to parking lots, with the lower bound of the estimate at 976 km2 and the upper bound at 1745 km2. This accounts for approximately 4.97% of urban land use and over 43 million parking spaces whereas the number of adults over 18 years old in these four states amounted to just over 25 million. The estimated number of spaces per vehicle in each state ranges from 2.49 in Indiana to 2.95 in Michigan. Within the four states studied, states that had a higher proportion of their urban land devoted to parking lots were states where urban sprawl was more prevalent.