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San Francisco, CA, United States

Willson R.,California State Polytechnic University, Pomona | O'Connor T.,Wilbur Smith Associates | Hajjiri S.,City of San Diego
Transportation Research Record | Year: 2012

Parking requirements should have a logical relationship with observed levels of parking use and with goals related to transportation, land use, and housing. These requirements are important elements of transportation policy because they influence vehicle ownership rates, travel choices, and mobility options. These local ordinances also shape land use outcomes, such as density, and social outcomes, such as housing affordability. This paper reports on a study of parking requirements for income-restricted, affordable multifamily housing. This form of land use is of particular interest because of its cost sensitivity and controversial nature. The study reported here used household surveys and overnight occupancy counts to assess the use of parking across varied types of income-restricted, affordable housing in the city of San Diego, California. Overall, the use of parking was found to be slightly less than one-half the rate for all rental units in San Diego but varied across affordable housing types (e.g., for families versus for seniors), location (e.g., access to mass transit, opportunity to walk), and bedroom count. This paper concludes with a discussion of methodologies to measure parking use and suggests a sequential policy process to establish affordable housing parking requirements. Source


Collura J.,University of Massachusetts Amherst | Heaslip K.P.,Utah State University | Moriarty K.,Vanasse Hangen Brustlin | Wu F.,University of Massachusetts Amherst | And 2 more authors.
Transportation Research Record | Year: 2010

As the National Highway System reaches the end of its serviceable life, transportation agencies increasingly need to focus on the preservation, rehabilitation, and maintenance of these roads. In light of significant increases in work zone activity, transportation officials and contractors are challenged to find ways to reduce the negative impacts on driver mobility. The key to addressing this challenge is to recognize potential impacts well in advance. One major tool used for this purpose is computer simulation. Many simulation models exist, some designed specifically for work zone analysis, including QUEWZ, QuickZone, CORSIM, and CA4PRS. This purpose of this paper is to present case studies that illustrate and evaluate these models for ease of use, data requirements, and ability to simulate and assess work zone strategies, shedding light on the relative reliability and accuracy of these simulation models as well as their user-friendliness and data requirements. This paper compares simulation results with actual work zone conditions in eight locations across New England. The results of this evaluation will be of interest to state and local transportation engineers responsible for planning and designing work zone strategies. This research has shown that some simulation models provide a low-risk, low-cost environment in which to test and analyze a variety of work zone alternatives. For example, QUEWZ and QuickZone were able to provide reasonable order of magnitude queue length estimates on Interstate highways that were comparable with observations made in the field. In addition, such estimates required few data, including hourly volume and roadway geometry information. Source


Rashidi T.H.,University of Illinois at Chicago | Mohammadian A.,University of Illinois at Chicago | Zhang Y.,Wilbur Smith Associates
Transportation Research Record | Year: 2010

Household and individual demographics, attributes, and dynamics have significant effects on travel behavior and the overall performance of the transportation system. This study attempts to examine the effects of household demographic changes on the travel attributes of households grouped into several homogeneous lifestyle clusters. With the use of the National Household Travel Survey 2001 data, more than 20 travel attributes including number of auto trips, trips per tour, transit usage, and average commute distance are analyzed. To investigate the impact of changing demographics on household- and individual-level travel attributes, the best-fit distributions for a large set of travel attributes are introduced. Then a detailed comparison between the resulting distributions across different lifestyles and demographics is presented. Source


Oricchio V.,Wilbur Smith Associates | Fox J.,Wilbur Smith Associates | Trepal R.,Wilbur Smith Associates
Transportation Research Record | Year: 2010

Connecticut Department of Transportation, with the support of the Transportation Strategy Board, is preparing an environmental assessment for commuter rail service between New Haven and Hartford, Connecticut, and Springfield, Massachusetts. The study area corridor is 62 mi of existing rail line, which is owned and operated by Amtrak. This rail corridor line is commonly referred to as the Springfield Line. Besides a regional passenger service, four freight carriers use the line: Connecticut Southern, Pan Am Railways, CSX Corporation, and Providence and Worcester Railroad. A limited section of double track and long freight dwellings along the main line both demanded multiple alternatives to be analyzed according to capacity improvements and operational changes. Analysis was conducted by means of the Rail Traffic Controller software. The commuter plan was analyzed under two main scenarios: a start-up near-term service (Year 2015) and a future service (Year 2030). The outer year testing also included an iteration of improvements given implementation of high-speed rail on the line. The purpose of this discussion is to identify the track capacity and operational requirements for an efficient integration of freight, Amtrak, commuter, and high-speed rail service. Source

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