Differences in Injury Severities Between 2-Vehicle and 3-Vehicle Crashes

<p><b>Objective and Methods:</b> In traditional injury severity–related studies, 2-vehicle and 3-vehicle crashes are typically considered in a combinatory manner and thus the injury casual factors for these 2 crash types are implicitly assumed to be the same. This article attempts to investigate the potential discrepancy between 2- and 3-vehicle crash severities with the aid of a continuation ratio logit model with the property of partial proportional odds.</p> <p><b>Results:</b> The modeling results show that there are a number of significant differences between 2- and 3-vehicle crash injury severities in terms of the contributing factors, the magnitude of impact, and even the direction of effects.</p> <p><b>Conclusions:</b> The research illustrates that a series of environmental and crash factors (e.g., rear-end straight crashes, urban roadways, alcohol usage, and different driving cohorts) are statistically significant in interpreting the disparity of coefficients between 2- and 3-vehicle crash injury severity models. It raises awareness that the combined analysis of 2- and 3-vehicle crashes should be exercised with caution, particularly when safety research targets crashes with less severe injuries.</p

Highly Reversible Zn–Air Batteries Enabled by Tuned Valence Electron and Steric Hindrance on Atomic Fe–N₄–C Sites

The bifunctional oxygen electrocatalyst is the Achilles’ heel of achieving robust reversible Zn–air batteries (ZABs). Herein, durable bifunctional oxygen electrocatalysis in alkaline media is realized on atomic Fe–N4–C sites reinforced by NixCo3–xO4 (NixCo3–xO4@Fe1/NC). Compared with that of pristine Fe1/NC, the stability of the oxygen evolution reaction (OER) is increased 10 times and the oxygen reduction reaction (ORR) performance is also improved. The steric hindrance alters the valence electron at the Fe–N4–C sites, resulting in a shorter Fe–N bond and enhanced stability of the Fe–N4–C sites. The corresponding solid-state ZABs exhibit an ultralong lifespan (>460 h at 5 mA cm–2) and high rate performance (from 2 to 50 mA cm–2). Furthermore, the structural evolution of NixCo3–xO4@Fe1/NC before and after the OER and ORR as well as charge–discharge cycling is explored. This work develops an efficient strategy for improving bifunctional oxygen electrocatalysis and possibly other processes