The interactive effect of alcohol and altitude on traffic fatalities.

• Author: Fowles, Richard
• Position: Communications

1. Introduction

   The fundamental maxims of driving are "speed kills" and "drinking and driving don't mix." A series of recent articles have analyzed these speed adages and based on the work of Lave[8; 9] and others, we now know that both speed and its variance kill.(1) In this paper we expand the analysis to investigate the potential for an interactive effect between alcohol and altitude on automobile fatality rates. We also examine a number of other policy and driving related variables. That drinking and driving don't mix is supported by Loeb [12; 13; 14], Levy and Asch [11], Sommers [18], and to some extent, Cook and Tauchen[4]. That the deleterious effects of alcohol on reaction time is more pronounced due to the diminished oxygen intake to the brain at higher elevations is physiologically supported in studies by Mazess, et al.[15] and Newman [16].(2) Our main finding is that the interaction between altitude and alcohol consumption may have a pronounced effect on traffic fatalities and largely explains the disproportionate fatality rates found in western regions of the United States.(3) In other words, drinking and driving don't mix, especially in the Rocky Mountains.

2. Data and Model

   The model used in this paper is based on elementary cross sectional state data for the contiguous 48 states.(4) The dependent fatality variable is an interstate motor vehicle fatality rate computed by the ratio of the number of traffic fatalities to the number of vehicle miles driven. Independent variables include:(5)

   AGE: Minimum legal drinking age.

   BEER: Per capita consumption of malt beverages.

   SPEED: Weighted average speed of free-moving vehicles driven on rural and urban interstate

   highways.(6)

   VAR: Weighted average speed variability of free-moving vehicies driven on rural and

   urban interstate highways.

   D: Dununy variable for inspection program; 1 for states with inspection program in

   effect, 0 otherwise.

   YOUTH: Percentage of the population between the ages of 18 and 24.

   ALT: An average of altitudes of metropolitan areas within a state.(7) ALTBEER: The interaction of ALT and BEER.

   Regression results for several model specifications are provided in Tables I (linear) and II (logarithmic).(8) Models are of the form:

   where [X.sub.ji] represent socioeconomic and driving related independent variables and [beta.sub.j] (j = 0, 1, . . .) represent parameters to be estimated.

   [TABULAR DATA OMITTED]

   Bayesian extreme bounds analysis (EBA) results, with attention to...