Speeding and Speed Modification of Older Drivers: Does Vehicle Type Make a Difference?

The purpose of this study was to examine whether vehicle type based on size (car vs. other = truck/van/SUV) had an impact on the speeding, acceleration, and braking patterns of older male and female drivers (70 years and older) from a Canadian longitudinal study. The primary hypothesis was that older adults driving larger vehicles (e.g., trucks, SUVs, or vans) would be more likely to speed than those driving cars. Participants (n = 493) had a device installed in their vehicles that recorded their everyday driving. The findings suggest that the type of vehicle driven had little or no impact on per cent of time speeding or on the braking and accelerating patterns of older drivers. Given that the propensity for exceeding the speed limit was high among these older drivers, regardless of vehicle type, future research should examine what effect this behaviour has on older-driver road safety.This study was funded by AUTO21, Manitoba Centres of Excellence Fund, and a Team Grant from the Canadian Institutes of Health Research (CIHR) entitled “The CIHR Team in Driving in Older Persons (Candrive II) Research Program” (grant 90429). Additional support was provided by the Ottawa Hospital Research Institute and the Toronto Rehabilitation Institute, University Health Network, and the University of Manitoba. Gary Naglie is supported by the George, Margaret and Gary Hunt Family Chair in Geriatric Medicine, University of Toronto. Michel Bédard was supported by a Canada Research Chair in Aging and Health during the development phase of this study. None of the funders were involved in any aspects of the study or the manuscript

Older driver estimates of driving exposure compared to in-vehicle data in the Candrive II study

ACKNOWLEDGMENTS We thank the Candrive Team, research associates and the older driver participants, without whose valuable contribution, this research would not be possible. We acknowledge with thanks Candrive's key partners: the National Association of Federal Retirees, Canadian Association for the Fifty-Plus (CARP), Municipal Retirees Organization Ontario, Canadian Council of Motor Transport Administrators and Transport Canada. No funding was received from Persen Technologies, and while they had no direct role in the study (design, data collection, interpretation of results, etc.), we do acknowledge the technical assistance they provided with their devices.OBJECTIVE: Most studies on older adults' driving practices have relied on self-reported information. With technological advances it is now possible to objectively measure the everyday driving of older adults in their own vehicles over time. The purpose of this study was to examine the ability of older drivers to accurately estimate their kilometers driven over one year relative to objectively measured driving exposure. METHODS: A subsample (n = 159 of 928; 50.9% male) of Candrive II participants (age >/= 70 years of age) was used in these analyses based on strict criteria for data collected from questionnaires as well as an OttoView-CD Autonomous Data Logging Device installed in their vehicle, over the first year of the prospective cohort study. RESULTS: Although there was no significant difference overall between the self-reported and objectively measured distance categories, only moderate agreement was found (weighted kappa = 0.57; 95% confidence interval, 0.47-0.67). Almost half (45.3%) chose the wrong distance category, and some people misestimated their distance driven by up to 20,000 km. Those who misjudged in the low mileage group (</=5000 km) consistently underestimated, whereas the reverse was found for those in the high distance categories (>/= 20,000); that is, they always overestimated their driving distance. CONCLUSIONS: Although self-reported driving distance categories may be adequate for studies entailing broad group comparisons, caution should be used in interpreting results. Use of self-reported estimates for individual assessments should be discouraged.This work was funded by a Team Grant from the Canadian Institutes of Health Research (CIHR) (grant number 90429). Gary Naglie is supported by the George, Margaret and Gary Hunt Family Chair in Geriatric Medicine, University of Toronto

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)