Fatal wrong-way collisions on New Mexico's interstate highways, 1990-2004.

Medical examiner files from 1990 through 2004 were reviewed to identify fatalities caused by drivers traveling the wrong direction on interstate highways and identify risk factors and prevention strategies. Other fatal nonpedestrian interstate motor vehicle crashes served as a comparison group. Data abstracted included decedent demographics, driver/passenger status, seatbelt use, blood alcohol concentration, weather and light at time of occurrence and types of vehicles involved. Of 1171, 79 (6.7%) interstate motor vehicle fatalities were because of drivers traveling against the posted direction in 49 crashes, with one to five fatalities per crash. Wrong-way collisions were significantly more likely to occur during darkness (p < 0.0001) and involve legally intoxicated drivers (p < 0.0001). In 29/49 (60%) wrong-way crashes, alcohol was a factor. Prevention strategies aimed at reducing the incidence of driving while intoxicated, as well as improved lighting and signage at ramps, could help reduce the occurrence of fatal wrong-way collisions on interstates.

Ab initio method for locating characteristic potential-energy minima of liquids.

It is possible in principle to probe the many-atom potential surface using density functional theory (DFT). This will allow us to apply DFT to the Hamiltonian formulation of atomic motion in monatomic liquids by Wallace [Phys. Rev. E 56, 4179 (1997)]. For a monatomic system, analysis of the potential surface is facilitated by the random and symmetric classification of potential-energy valleys. Since the random valleys are numerically dominant and uniform in their macroscopic potential properties, only a few quenches are necessary to establish these properties. Here we describe an efficient technique for doing this. Quenches are done from easily generated "stochastic" configurations, in which the nuclei are distributed uniformly within a constraint limiting the closeness of approach. For metallic Na with atomic pair potential interactions, it is shown that quenches from stochastic configurations and quenches from equilibrium liquid molecular dynamics configurations produce statistically identical distributions of the structural potential energy. Again for metallic Na, it is shown that DFT quenches from stochastic configurations provide the parameters which calibrate the Hamiltonian. A statistical mechanical analysis shows how the underlying potential properties can be extracted from the distributions found in quenches from stochastic configurations.