Methodology of parking analysis

Cities are faced with many challenges, in particular in relation to the mobility of people and the structure of land-use. Parking management, which makes the link between the fields of urban planning and transportation, is one of the crucial ways to meet these challenges. However, parking studies are a poorly covered area in transportation research. The main barrier to study parking is parking data availability. In the Greater Montreal Area, data from origin-destination (OD) surveys are helpful in understanding typical travel behavior. These surveys have been conducted for forty years and provide useful data to describe and model various spatial-temporal features of daily mobility. This research illustrates the use of OD survey data to develop indicators on parking spaces and use in a given area. This study confirms that the systematic processing of car driver trips from travel surveys allows developing vehicle accumulation profiles for various zones and, from these, derive theoretical parking capacities. This research provides an assessment of the quality of the estimation by comparing the estimations from OD survey to other sources of data, namely geographical data and field surveys. The paper shows that parking capacity is subject to high variability and highlights that its assessment is quite complex and must take into account regulation data that modulates the availability of the raw parking capacity according to different days and hours of the day. Diallo, Morency and Saunier 3 INTRODUCTION The paradox of transportation vehicles is that they are most studied when they are the least used, i.e. when they are in motion, while they spend most of their time stationary or parked. For example, taking into account only the commute to work, which was measured to be on average 27 minutes by car in the six largest Canadian census metropolitan areas [1], cars are used less than 4 % of the day. Despite the importance of the phenomenon, “parking is the unstudied link between transportation and land use” as stated by Shoup [2] in his seminal work. There are several reasons to that, an essential one being the cost or difficulty to collect or have access to such data. To address this need, this work illustrates the assessment of parking capacity of a given area using data collected in origin-destination (OD) household surveys. This paper uses a method developed by Morency et al. [3] based on vehicle accumulation profiles and proposes two methods to validate the estimates of parking capacity using data from two sources: several GIS sources and a field survey. It relies in particular on the latest OD survey conducted in the Greater Montreal Area in 2008. The outline of this paper is as follows: after the introduction, we present a brief background, then the research methodology, the results of the application of the method to a borough of Montréal, and finally a conclusion with recommendations for future work. BACKGROUND In the field of Transportation, the phenomenon of parking, although essential, proves to be one of the least studied. Data collection in the field of parking studies is a major challenge. The diversity of parking types and the multiple variations of their vocations contribute to this difficulty. The Institute of Transportation Engineers presents several methods of data collection to analyze the parking spaces, their usages and their users [4]. Roess, Prasas and McShane provide a standard textbook approach to parking data collection and analysis [5]. Parking users have also been studied, for example the factors that may affect their choice of parking such as price and walking distance to the final destination. Weant and Levinson argue that the walking distance is competing with the cost of parking [6]. Habib et al. investigate the relationship between parking choice and activity-travel scheduling behaviour also using the 2008 OD survey data from Montreal [7]. They show that activity scheduling decisions of car drivers are significantly influenced by parking choice (being reflected in parking type and space availability). Several authors such as Bergman [8], Badland & al.[9], Cavaya & Baudouin [10], Coates [11], Darbéra [12], Engel-Yan & Passmore [13], Ferguson [14], Jakle & Sculle [15], Robert [16] and Willson [17] focus on less tangible areas of the parking problem, ranging from the perception of safety or comfort by the users of parking spaces, the impacts of laws, regulations and parking policies on communities and modal choices [18]. Shoup supports that for users of the parking spaces, the perception of the comfort of the sidewalk, between the parking area and the final destination, increases the tolerated walking distance [19]. In that line of thought, Litman advocates a new paradigm for parking policy which takes into account more urban planning concepts such as the integration of parking spaces in their neighborhoods [20]. Regarding the impact of laws and regulations, most studies argue for a greater tightening of laws governing parking. Marsden conducted a literature review that contradicts the theory that fewer parking spaces in business centers and retail areas contribute to their impoverishment [21]. Shoup highlights the inequalities between car drivers and people using other modes vis-à-vis the regulations and parking policies in several North American cities [2]. He argues that subsidy policies and free parking lead to increases in costs of goods and services, shared by all citizens, including those who do not use cars. Meanwhile, Litman, demonstrates how laws governing the parking spaces requirement have an impact on housing affordability [22]. Despite the diversity of areas for parking, most authors agree on the fact that more accurate parking data would contribute to better decision making. Diallo, Morency and Saunier 4 This work builds upon the research by Morency et al. [3] and Tong et al. [23]. These authors have proposed a methodology to estimate parking capacity in various areas using travel survey data. Their method relies on the spatial-temporal monitoring of cars in the region using declared car driver trips. With their 5 % sampling, the Montreal travel surveys have sufficient data to allow for specific analysis. The method also relies on declared information on the type of parking space used at the destination. It is hence possible to cumulate cars in space throughout a typical day and to estimate a theoretical parking capacity using the maximum number of cars simultaneously parked in an area.