Some biases in the alcohol investigative process in traffic fatalities

Abstract

This study compares data regarding alcohol involvement from police records and from chemical analyses of body fluids taken prior to or after death of 121 traffic fatalities in Washtenaw County, Michigan. Differences regarding the choice of who will or will not be screened for alcohol were found. The police and emergency room personnel were more likely to focus on males and drivers, while medical examiners were less biased. The police documented whether or not drinking took place in only 36% of the cases and suspected drinking in only half of these cases. Males and at-fault drivers were most likely to be investigated. Blood alcohol level was measured before death in 11 of 29 emergency room treated victims, with 10 (91%) positive samples. All but two of those tested before death were drivers, and all but one were males. After death, blood alcohol was measured in 47% of the 121 cases, with a higher proportion of males and motor-vehicle occupants tested, compared to females and pedestrians. Alcohol was detected in 63% of the samples. A lower mean blood alcohol concentration was found in victims who received intravenous treatment, and a higher proportion of positive samples was found in victims who died immediately in the crash. Thus, the frequency of alcohol-related traffic fatalities varied between the different data sources. The police records revealed 51%, the emergency records 91%, and the medical examiner records 63% with alcohol involvement. This wide discrepancy has the potential of leading to erroneous results here and possibly in studies done elsewhere.(ABSTRACT TRUNCATED AT 250 WORDS)

Fatal traffic injuries among pedestrians, bicyclists and motor vehicle occupants

“…Driving under the influence of alcohol is a major cause of road traffic accidents in Europe as well [36,[38][39][40]. In our series alcohol test was positive in 49.7%, and 42% was above the legal limit.…”

Driver dependent factors and the risk of causing a collision for two wheeled motor vehicles

“…[30][31][32][33] The sample used in the present study is probably not representative of all CC with victims in which TWMVs were involved, because the degree of underreporting of traffic crashes in urban areas (where most of the crashes involving TWMVs take place) is especially high in Spain. Furthermore, because the degree of underreporting usually correlates inversely with severity of the crash, 30 31 our sample probably overestimated the proportion of severe crashes involving TWMVs.…”

Association of main driver-dependent risk factors with the risk of causing a vehicle collision in Spain, 1990–1999

“…Only the value for alcohol use documented by a positive breath test reached a figure higher than 3%, which is much lower than the figures reported in earlier studies (43,47). As noted before (26,27), police officers probably tend to underreport some of these psychophysical alterations, perhaps because they record them only when the driver shows obvious signs of such alteration.…”

“…Unfortunately, the quality and completeness of the DGT traffic crash database have yet to be assessed. We must therefore assume that these data are affected by the same problems as have been described previously for similar databases in other countries, i.e., under-representation of less severe accidents (9,23,24) and an undetermined degree of inaccuracy for driver-related variables (25)(26)(27). Inaccuracies in the ascription of infractions to each driver have been noted previously.…”

“…In addition, our results once again document the effect of alcohol consumption on the risk of being involved in a traffic crash (33,34,(41)(42)(43). The large increase in both crude and adjusted OR estimates for drivers with a positive breath test in comparison to drivers under the influence of alcohol but who did not take a breath test may reflect the joint effect of several factors: (a) information bias in the police officers' visual assessment of the drivers' sobriety (27), (b) other information bias if police officers tended to request a breath test only if they believed that the driver had committed an infraction in this crash (26), and (c) an approximately dose-dependent relationship between alcohol consumption and the risk of causing a collision, assuming that police officers tended to request a breath test more frequently if the driver presented evident signs of inebriation. Although the association we found between use of illicit drugs and the risk of causing a collision is in agreement with earlier findings (27,33,(44)(45)(46), an unbiased estimation of this effect would require an unbiased measurement of drug-related variables, a type of information which is not recorded in the DGT register.…”