Travel and Parking Behavior in the United States

Transportation Research Record, 2015

Parking is among the most discussed topics in local politics, with citizens and business owners frequently concerned about supplies being too low. However, numerous research efforts have shown that parking is routinely oversupplied in single-use districts in the United States, and others have documented the same trend in mixed-use districts. This paper looks at parking supply and usage in an additional 27 mixed-use districts around the country, the largest sample of districts examined in this type of study. Defining sufficient supply as that which would leave 15 percent of spaces open, we find that parking is oversupplied by 65% on average. Differences in oversupply are not systematically explained by commute mode share, region, type of place, or any other dimension we were able to identify. Indeed, oversupply in places that have identified parking shortages averages 45%. The finding suggests that parking is often oversupplied to such an extent that it is non-binding on travel decisions and has become unmoored from the typical relationship between supply and demand. Given the perception of shortage even where there is a documented oversupply suggests that better parking management could be a more effective tool for mitigating perceived shortages than would an increase in supply.

Transportation Research Record, 2015

Parking is among the most discussed topics in local politics, with citizens and business owners frequently concerned about supplies being too low. However, numerous research efforts have shown that parking is routinely oversupplied in single-use districts in the United States, and others have documented the same trend in mixed-use districts. This paper looks at parking supply and usage in an additional 27 mixed-use districts around the country, the largest sample of districts examined in this type of study. Defining sufficient supply as that which would leave 15 percent of spaces open, we find that parking is oversupplied by 65% on average. Differences in oversupply are not 8 systematically explained by commute mode share, region, type of place, or any other dimension we were able to identify. Indeed, oversupply in places that have identified parking shortages averages 45%. The finding suggests that parking is often oversupplied to such an extent that it is non-binding on travel decisions and has become unmoored from the typical relationship between supply and demand. Given the perception of shortage even where 12 there is a documented oversupply suggests that better parking management could be a more effective tool for mitigating perceived shortages than would an increase in supply. INTRODUCTION 2 Concerns about parking shortages are common in cities and towns across the United States. But with more than two spaces supplied per vehicle (1), there is clearly no universal shortage. As drivers move between residential and commercial areas in well-timed pulses, downtown in the daytime and back home in the evening, they may experience spot shortages, but even then, a question of scale arises. Is it a shortage because the one "best" space a driver wants is occupied, because all the spaces on the destination street or the first floors of a garage are occupied, or because there are no spaces to be found in a wider area? Even San Francisco, a city so notorious for parking 8 shortages that the U.S. Department of Transportation invested approximately $18 million to develop a pricing system that could, in theory, redistribute and/or reduce demand, found that simply redistributing demand geographically solved the "shortage." While the city raised parking prices on many streets, it kept prices the same or lowered prices on more streets and lowered garage prices repeatedly over the two years of the pilot to attract 12 motorists from the crowded curb into un-crowded, but nearby, garages (2). Yet, the perception of parking shortages plays an important role in discussions about planning and development in many cities. Business owners worry about losing customers because of parking shortages, visitors about the hardship of not finding parking near their destinations, and residents about increased traffic and parking on residential streets adjacent to mixed-use districts. Dynamics like the shift in housing demand from detached singlefamily developments on the suburban fringe toward denser developments closer in (3) have brought this issue to the 18 forefront in many cities over the last 10 years. At the same time, there is a growing recognition of the downsides of providing too much parking, from the high cost of building structured parking and the opportunity costs of using prime land for surface parking lots to the environmental, social, and travel-behavior impacts of parking facilities. This study looks at parking supply and demand in 27 mixed-use districts across the country. The 27 studies 22 are culled from a longer list of studies completed in mixed-use town and city centers over the last 10 years. Some of those studies were initiated as updates to comprehensive plans, some as precursors to growth plans, and others were specifically due to a city's or town's desire to address a parking shortage. We summarize observed occupancy rates relative to a theoretical occupancy target that would leave 15 percent of spaces open, i.e. the amount generally believed to be necessary to ensure a smooth functioning parking system (4); and we look at occupancy rates in light of the main reasons cities initiated each study. 28 The evidence suggests that parking is routinely oversupplied in mixed-use districts, including those in which a parking study was initiated because of perceived deficiencies in supply. This finding holds regardless of the commute mode choices of local workers or the density of the surrounding area. It suggests that mixed-use districts may benefit more from robust parking management than from increasing supply and it adds to a growing body of 32 literature that shows significant levels of oversupply in a variety of contexts, suggesting that municipalities of all kinds could require and build less parking without causing any perceptible change in parking availability or access mode choices. BACKGROUND 38 Because of public concerns about the parking and traffic impacts of new developments, parking requirements have been written into zoning ordinances for several decades. For nearly as long, planners and engineers have been trying to inform these requirements by estimating the amount of parking demand different land uses generate. The Institute of Transportation Engineers' Parking Generation is perhaps the best known and most widely 42 used example of these efforts. Now in its fourth edition, the guidebook summarizes the results of voluntarily submitted parking-occupancy studies for 106 land uses, reporting the average, 85 th percentile, and 33 rd percentile ratios of peak-period parking occupancy to built square footage or a similar measure of project size (i.e. the number of employees in an office building or seats in a restaurant) for each land use type (5). Almost all parking studies included in the manual are from suburban sites with free parking and isolated single land uses, and though the manual's two most recent editions encourage studies from sites with a "variety of characteristics," the need to tie 48 parking behavior to a particular land use has thus far limited the manual's scope. Coverage of parking generation in mixed-use environments is limited to a short appendix highlighting six examples. The same six examples appear in the manual's third and fourth editions. While the guidebook is careful to note that it is informational and does not provide authoritative findings, recommendations, or standards on parking demand, the estimates it provides are, 52 nevertheless, frequently cited as a starting place for analyzing and understanding parking demand. The Urban Land Institute and the International Council of Shopping Centers has attempted to correct for the lack of mixed-use sites in Parking Generation with their Shared Parking manual, now in its second edition (6). The manual creates a framework for estimating parking demand in settings like shopping centers, in which parking

Zhang M, Mulholland K, Zhang J, and Gomez-Sanchez A., 2012

Increasingly MPOs in Texas are incorporating Transit-Oriented Development (TOD) or similar concepts into their long-range plans for the purpose of achieving sustainable transportation. One major challenge to implementing these TOD-type strategies is parking. The conventional parking policies likely produce excessive parking, undermining the expected community benefits of TOD and could even cause the TOD initiative to fail. Getting the parking right is essential to ensure the desirable form and functionality of TOD. There are few studies of the topic on Texas cities. The main objective of this study is to report the state-of-the-knowledge on parking regulations and practice influencing the planning, design, and implementation of TOD. The report first offers a narrative review of the published works on TOD-Parking. Based on the review findings it then presents a matrix of best parking practices for TOD. Finally, the report provides an annotated bibliography of TOD-Parking studies. Appendix 1 assembles parking regulations and practice policies in selected cities in the Austin-Round Rock Metropolitan Statistical Area.

2006

This paper presents the evaluation of the commute travel effects of the first transit-based smart parking project in the U.S. at the Rockridge Bay Area Rapid Transit (BART) District station in Oakland, California. The following are key findings from the analysis of participant survey travel results: 1) sizable increases in BART mode share (an average increase of 5.5 and 4.0 more BART trips per month for on-site and off-site commutes, respectively); 2) reductions in drive alone modal share (30.8 and 56%, across frequencies, would have driven to on-site and off-site work locations, respectively, without smart parking); 3) decreased average commute time (47.5 minutes using smart parking and BART compared to in 50.1 minutes without smart parking); and 4) reduction in total vehicle miles traveled (VMT) (on average, 9.7 fewer VMT per participant per month).

Journal of Transport Geography, 2013

This paper investigates the impact of residential parking supply on private car ownership, the relationship at the heart of the debate on whether residential parking regulations could be used as a demand management strategy to influence travel behavior. However, no empirical studies have sufficiently answered the question. Many believe that parking has little or no effect on car ownership, while others disagree. The paper analyzes 770 households randomly selected from a household travel survey in the New York City region, and measures their complete parking supply, including garage size, driveway spaces, and on-street parking availability, using Google Streetviews and Bing Maps. Results from a nested logit model show that parking supply can significantly determine household car ownership decisions, even after controlling for the endogeneity between the two. Their influence actually outperforms household income and demographic characteristics, the often-assumed dominant determinants of car ownership. Different parking types also behave differently: driveway spaces are more important to car ownership than garages probably because many residents in the study region do not use a garage for car storage. On-street parking is also important to households with off-street parking. Implications for residential parking policies like the maximum off-street parking standard, resident parking permit, and street cleaning are also discussed.