Does Car-Sharing Reduce Car Ownership? Empirical Evidence from Germany

The sharing economy is making its way into our everyday lives. One of its business models, car-sharing, has become highly popular. Can it help us increase our sustainability? Besides emissions and vehicle miles traveled, one key aspect in the assessment regards the effect of car-sharing on car ownership. Previous studies investigating this effect have relied almost exclusively on surveys and come to very heterogeneous results, partly suggesting spectacular substitution rates between shared and private cars. This study empirically explores the impact of car-sharing on noncorporate car ownership and car markets in 35 large German cities. The analysis draws on publicly available data for the years 2012, 2013, 2015, and 2017, including, among others, the number of shared cars per operating mode (free-floating and station-based) and the number of cars owned and registered by private individuals (i.e., excluding company cars). We find that one additional station-based car is associated with a reduction of about nine private cars. We do not find a statistically significant relation between car ownership and free-floating car-sharing. Neither type of car-sharing appears to impact the markets for used and new cars significantly. Given the measurable impacts on car ownership levels, this result is surprising and invites future research to study car-sharing’s impact on the dynamics of car markets.

Seismically Detecting Nuclear Reactor Operations Using a Power Spectral Density (PSD) Misfit Detector

ABSTRACT To explore the ability to indirectly detect and attribute various operations conducted at a nuclear reactor using waveform data, we investigated the seismic signals recorded near the High Flux Isotope Reactor (HFIR) located at Oak Ridge National Laboratory in Oak Ridge, Tennessee. Specifically, we processed seismic data collected from a single seismoacoustic station, WACO, near the HFIR facility, and employed a power spectral density misfit detector to identify signals of interest and associate the detections with operational events. Initial results suggest that this method provides a promising means of regularly detecting at least 19 unique operations. With additional station deployment and more comprehensive data logs, we anticipate that future analysis will offer an additional means to seismically monitor nuclear reactors (such as HFIR) health and performance more accurately.

Future TRFs and GGOS – where to put the next SLR station?

Satellite Laser Ranging (SLR) is one of the four geodetic space techniques contributing to the realisation of terrestrial reference frames (TRFs) as well as to the determination of Earth Rotation Parameters (ERPs). The current SLR tracking network suffers from an insufficient network geometry due to a lack of stations especially in the southern hemisphere. Previous simulation studies have shown that the extension of the global SLR tracking network is indispensable for reaching the target accuracy of future TRFs according to user requests and the ambitious goals of the Global Geodetic Observing System (GGOS). The simulation study presented here puts the focus on a determination of the locations where additional SLR stations are most valuable for an improved estimation of the geodetic parameters. Within the present study, we perform a simulation of a set of stations distributed homogeneously over the globe and compare different solutions, always adding one of these simulated stations to the real SLR station network. This approach has been chosen in order to be able to investigate the deficiencies of the existing SLR network and to judge in which regions on the globe an additional SLR station would be most valuable for the improvement of certain geodetic parameters of SLR-derived reference frames. It is shown that the optimum location of a future SLR station depends on the parameter of interest. In case of the ERPs, the main potential for improvement by a single additional station can be shown for locations in polar regions (improvement for ypole up to 7 %) and for locations along the equator for the lengh of day (LOD, improvement up to 1.5 %). The TRF parameters would benefit from an additional station around the pierce points of the axes of the terrestrial reference frame (improvement for ty up to 4 %), the Arctic and the Pacific Ocean region (tz improved by up to 4.5 %), and the Antarctic and the Indian Ocean region (scale improved by up to 2.2 %). As outcome of this study, it is concluded that an additional SLR site in the Antarctic region might be of first priority, enabling improvements in the pole coordinates and the scale of the TRF; potential further sites are recommended in the equatorial region, especially beneficial for the origin of the realised TRF as well as for LOD.

Improved Historical Temperature and Precipitation Time Series for U.S. Climate Divisions

This paper describes an improved edition of the climate division dataset for the conterminous United States (i.e., version 2). The first improvement is to the input data, which now include additional station networks, quality assurance reviews, and temperature bias adjustments. The second improvement is to the suite of climatic elements, which now includes both maximum and minimum temperatures. The third improvement is to the computational approach, which now employs climatologically aided interpolation to address topographic and network variability. Version 2 exhibits substantial differences from version 1 over the period 1895–2012. For example, divisional averages in version 2 tend to be cooler and wetter, particularly in mountainous areas of the western United States. Division-level trends in temperature and precipitation display greater spatial consistency in version 2. National-scale temperature trends in version 2 are comparable to those in the U.S. Historical Climatology Network whereas version 1 exhibits less warming as a result of historical changes in observing practices. Divisional errors in version 2 are likely less than 0.5°C for temperature and 20 mm for precipitation at the start of the record, falling rapidly thereafter. Overall, these results indicate that version 2 can supersede version 1 in both operational climate monitoring and applied climatic research.

Architecture for the Boston & Albany Railroad: 1881-1894

Between 1881 and 1894 the Boston & Albany Railroad undertook a major program of capital investment and improvements to the physical facilities of the line, including the construction of over 30 new passenger stations. H. H. Richardson's close friends, James A. Rumrill and Charles S. Sargent, as the two members of the B&A Board most interested in construction, were given responsibility for this program. They directed the commissions to Richardson and after his death to his successors, Shepley, Rutan and Coolidge. Richardson's nine B&A station designs were generally variations on a simple theme-small rectangular stone blocks with overhanging roofs providing sheltered waiting space at trackside. The continuation of this approach by Shepley, Rutan and Coolidge in 23 additional station designs resulted in a remarkable consistency of character and quality throughout the B&A system. This consistency was also fostered by the continuing participation of Norcross Brothers of Worcester (Richardson's "Master Builder") as contractor, and by the participation of F. L. Olmsted, whose design of landscaped settings for many of the stations contributed to the establishment of the B&A program of "railroad gardening." While the stations were small commissions, the totality of the B&A program represents an impressive collaboration of designer, contractor, and client which has seldom been equalled.

19. Commission de la Variation des Latitudes

The values given below are those published in every annual report of the international latitude work. Those for the first three years were calculated from the observed results in three stations, namely, Mizusawa, Carloforte and Ukiah, while that for the last year was from the results of four stations with one additional station, Kitab.

Report on Physical Investigations

The unusually severe weather of the last eight months has made it impossible to continue the observations in the Channel with any degree of regularity; only two trips have been made since that in June, of which a preliminary report was published in the last number of the Journal. The first of these, in November, included station VIII of the previous cruise, off the Bill of Portland in mid-channel, and the previous stations XIII and XIV, in Start Bay, also station I off Bolt Head. Besides these, soundings were taken at an additional station in mid-channel, south of Start Bay, and at four points in Start Bay itself, near land. The cruise was unfortunately interrupted by a gale which necessitated taking shelter for thirty-six hours in Portland Roads.