PubMed · 16329289
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
J R Weaver. 1968. A simple occupant dynamics model.. https://doi.org/10.1016/0021-9290(68)90003-1
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The adoption of higher rural interstate speed limits may shift behaviors in ways that broadly affect motor vehicle safety. In particular, these laws may attract drivers from less safe rural noninterstate roadways, implying that any negative implications of higher speed limits for rural interstate fatalities may be attenuated by fewer rural noninterstate fatalities. We test for the reallocation of vehicle miles traveled and fatalities using 1982-2002 U.S. data spanning the relaxation and repeal of the national maximum speed limit (NMSL) across all drivers and specifically those younger and older drivers associated with higher fatality risks. Overall, we find that the repeal of the NMSL resulted in a 36-37% increase in fatalities on rural interstate highways. However, we found very little support for any decrease in rural noninterstate driving or fatalities following the adoption of higher speed limits on rural interstates.
The relative motion of the brain with respect to the skull has been widely studied to investigate brain injury mechanisms under impacts, but the motion patterns are not yet thoroughly understood. This work analyzes brain motion patterns using the most recent and advanced experimental relative brain/skull motion data collected under low-severity impacts. With a minimum total pseudo-strain energy, the closed-form solutions for rigid body translation and rotation were obtained by matching measured neutral density target (NDT) positions with initial NDT positions. The brain motion was thus separated into rigid body displacement and deformation. The results show that the brain has nearly pure rigid body displacement at low impact speed. As the impact becomes more severe, the increased brain motion primarily is due to deformation, while the rigid body displacement is limited in magnitude for both translation and rotation. Under low-severity impacts in the sagittal plane, the rigid body brain translation has a magnitude of 4-5 mm, and the whole brain rotation is on the order of +/-5 degrees.
Transient whole-body surge (fore-aft) translation at 0.5 G peak acceleration was administered to six subjects with unilateral vestibular deafferentation (UVD), and eight age-matched controls. Subjects viewed eccentric targets to determine if linear vestibulo-ocular reflex (LVOR) asymmetry might lateralize otolith deficits. Eye rotation was measured using magnetic search coils. Immediately before surge, subjects viewed a luminous target 50 cm away, centered or displaced 10 degrees horizontally or vertically. The target was extinguished during randomly directed surges. LVOR gain relative to ideal velocity in subjects with UVD for the contralesional horizontally eccentric target (0.59 +/- 0.08, mean +/- SEM) did not differ significantly from normal (0.50 +/- 0.04), but gain for the ipsilesional eccentric target (0.35 +/- 0.02) was significantly less than normal (0.48 +/- 0.03, P < 0.05). Normal subjects had mean gain asymmetry for horizontally eccentric targets of 0.17 +/- 0.03, but asymmetry in UVD was significantly increased to 0.35 +/- 0.05 (P < 0.05). Four of six subjects with UVD had maximum gain asymmetry outside normal 95% confidence limits. Asymmetry did not correlate with UVD duration. Gain for 10 degrees vertically eccentric targets averaged 0.38 +/- 0.14 for subjects with UVD, insignificantly lower than the normal value of 0.75 +/- 0.15 (P > 0.05). Surge LVOR latency was symmetrical in UVD, and did not differ significantly from normal. There was no significant difference in response between dark and visible target conditions until 200 ms after surge onset. Chronic human UVD, on average, significantly impairs the surge LVOR for horizontally eccentric targets placed ipsilesionally, but this asymmetry is small relative to interindividual variation.