13,111 research outputs found
Residential On-Site Carsharing and Off-Street Parking Policy in the San Francisco Bay Area, Research Report 11-28
In light of rising motorization, transportation planners have increasingly supported alternatives to the indiscriminate use of the car. Off-street parking policy and carsharing have emerged as credible alternatives for discouraging car ownership. This report explores an initiative that could connect these policy fields and build on their synergy: the provision of on-site carsharing service in residential developments. It evaluates the performance of on-site carsharing programs in the San Francisco Bay Area by interviewing developers, planners, and carsharing service providers. Interviews were conducted in four Bay Area cities that support the provision of carsharing as an alternative to the private automobile. Based on these interviews, this report identifies the principal factors contributing to the success or failure of on-site carsharing: the unbundling status of off-street parking in residential developments; ties to off-street parking standards; financial constraints; and the level of coordination among stakeholders. The interviews revealed that on-site carsharing has been accepted by developers, planners, and service providers, particularly in densely-populated, transit-rich communities. Nevertheless, there appears to be a gap between on-site carsharing programs and off-street parking standards, and between carsharing programs and carsharing business operations. The authors recommend that a few models for establishing carsharing policy be tested: a model designed to serve high-density cities with traditional carsharing; and another designed to serve moderately-dense communities, with new carsharing options (e.g., peer-to-peer). In the case of the latter, trip reduction can be achieved through the promotion of alternative modes along major corridors
Amenity or Necessity? Street Standards as Parking Policy, Research Report 11-23
This paper explores the rationales underlying the use of minimum street width requirements to mandate street parking. A survey of 97 cities reveals that this mandate is not a technical necessity based on safety concerns or an amenity reflecting market demand, two common beliefs held by decision-makers. Many residents are likely unwilling to pay for street parking if it is unbundled from housing. The hidden parking policies should be made transparent and subject to public oversight, the double standard between private and public streets should be eliminated, and parking on residential streets should be optional
Active Travel Co-Benefits of Travel Demand Management Policies that Reduce Greenhouse Gas Emissions, MTI Report 12-12
There is increasing evidence that improved health outcomes may be significant co-benefits of land use plans and transport policies that increase active transport (or walking and biking for purposeful travel) and reduce greenhouse gas emissions (GHGs) from vehicle miles traveled (VMT). A greater understanding of these benefits may broaden the constituency for regional planning that supports local and national GHG reduction goals. In this study, California’s activity-based travel demand model (ABM) is applied to (1) demonstrate how this new generation of travel models can be used to produce the active travel data (age and sex distributions) required by comparative risk assessment models to estimate health outcomes for alternative land use and transport plans and to (2) identify the magnitude of change in active travel that may be possible from land use, transit, and vehicle pricing policies for California and its five major regions for a future 2035 time horizon. The results of this study suggest that distance-based vehicle pricing may increase walking by about 10% and biking by about 17%, and concurrently GHG from VMT may be reduced by about 16%. Transit expansion and supportive development patterns may increase active travel by about 2% to 3% for both walk and bike modes while also reducing VMT by about 4% on average. The combination of all three policies may increase time spent walking by about 13% and biking by about 19%, and reduce VMT by about 19%
The California General Plan Process and Sustainable Transportation Planning, MTI Report 01-18
This study reviewed the current and potential utility of California’s General Plan process as a tool for promoting more sustainable local transportation systems The study used multiple methods to investigate this issue, including: An extensive literature review on California’s General Plan process, the nature of sustainability and sustainable transportation, and criteria and evaluation methods for plans. Detailed analysis and scoring of policies from 26 exemplary General Plans against criteria designed to measure both transport sustainability and plan quality. In-depth case studies of the General Plan process in seven diverse California communities. Key informant interviews. The results of these several lines of analysis and inquiry were synthesized into a series of observations, conclusions and recommendations. Chief among these are the desirability of encouraging more frequent General Plan updates, the need for greater emphasis on implementation of plan policies, and the need for and utility of educational and outreach efforts aimed at enhancing the proliferation of General Plan policies that promote more sustainable transportation systems at the local level
REGIONAL COST SHARE NECESSARY FOR RANCHER PARTICIPATION IN BRUSH CONTROL
Large-scale brush-control programs are being proposed in Texas to increase off-site water yields. Biophysical and economic simulation models are combined to estimate the effects of brush control on representative ranches in four ecological regions of the Edwards Plateau area of Texas. Net present values of representative ranches in three of four regions decrease with brush control. Cost shares necessary for ranches from the three regions to break even range from 7% to 31% of total brush-control costs. Any large-scale brush-control program will therefore require a substantial investment by the state of Texas.Agribusiness,
Caveolin-1 regulates lipid droplet metabolism in endothelial cells via autocrine prostacyclin–stimulated, cAMP-mediated lipolysis
FDTD analysis of the tunneling and growing exponential in a pair of epsilon-negative and mu-negative slabs
Pairing together material slabs with opposite signs for the real parts of
their constitutive parameters has been shown to lead to interesting and
unconventional properties that are not otherwise observable for single slabs.
One such case was demonstrated analytically for the conjugate (i.e.,
complementary) pairing of infinite planar slabs of epsilon-negative (ENG) and
mu-negative (MNG) media [A. Alu, and N. Engheta, IEEE Trans. Antennas Prop.,
51, 2558 (2003)]. There it was shown that when these two slabs are juxtaposed
and excited by an incident plane wave, resonance, complete tunneling, total
transparency and reconstruction of evanescent waves may occur in the
steady-state regime under a monochromatic excitation, even though each of the
two slabs by itself is essentially opaque to the incoming radiation. This may
lead to virtual imagers with sub-wavelength resolution and other anomalous
phenomena overcoming the physical limit of diffraction. Here we explore how a
transient sinusoidal signal that starts at t = 0 interacts with such an ENG-MNG
pair of finite size using an FDTD technique. Multiple reflections and
transmissions at each interface are shown to build up to the eventual steady
state response of the pair, and during this process one can observe how the
growing exponential phenomenon may actually occur inside this bilayer.Comment: 14 pages, 9 figures, submitted to Phys Rev
Extreme response bias in measuring susceptibility to smoking.
Pierce, Choi, Gilpin, Farkas, and Berry (1998) were the first to claim that they could provide causal evidence that tobacco industry advertising and promotion caused adolescent smoking. This claim continues to significantly influence the theory and conceptualization of how youth react to tobacco marketing. The Pierce et al. (1998) methodology has been used by many researchers to establish the influence of tobacco marketing on adolescent smoking (Goldberg, 2003; NCI, 2006; Sargent, Dalton, & Beach, 2000). Pierce et al. (1998) selected respondents for only the second of their two survey longitudinal study because they chose the extreme-negative response. This choice could be the result of the tendency of some significant number of sample members exhibiting extreme-response bias. The results from an analysis of several questions from the original data used by Pierce et al. (1998) has suggested that there is a significant extreme-response style pattern in the Pierce et al. data. This unaccounted for bias in the responses of their sample was due to the procedure used by Pierce et al. (1998) in the selection of their respondents. The Pierce et al. (1998) sample selection procedure requires more research before the causal link can be claimed.<br /
Measurement of the Hyperfine Structure and Isotope Shifts of the 3s23p2 3P2 to 3s3p3 3Do3 Transition in Silicon
The hyperfine structure and isotope shifts of the 3s23p2 3P2 to 3s3p3 3Do3
transition in silicon have been measured. The transition at 221.7 nm was
studied by laser induced fluorescence in an atomic Si beam. For 29Si, the
hyperfine A constant for the 3s23p2 3P2 level was determined to be -160.1+-1.3
MHz (1 sigma error), and the A constant for the 3s3p3 3Do3 level is -532.9+-0.6
MHz. This is the first time that these constants were measured. The isotope
shifts (relative to the abundant isotope 28Si) of the transition were
determined to be 1753.3+-1.1 MHz for 29Si and 3359.9+-0.6 MHz for 30Si. This is
an improvement by about two orders of magnitude over a previous measurement.
From these results we are able to predict the hyperfine structure and isotope
shift of the radioactive 31Si atom, which is of interest in building a scalable
quantum computer
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