Alcohol and drugs use among drivers injured in road accidents in Campania (Italy): A 8-years retrospective analysis

Abstract

A recent update of the Italian Road Traffic Law (RTL 41/2016), established severe penal sanctions when drivers, driving under the influence of alcohol (DUI) or drugs (DUID), are involved in road accident that results in death or injuries. A study was carried out to assess the trends of consumption of alcohol, illicit drugs or pharmaceutical among injured drivers suspected for DUI or DUID from 2009 to 2016 in the region of Campania (Italy). Confirmation toxicological analyses were performed on 780 blood samples and 1017 urine samples collected from 1797 injured drivers. These drivers all tested positive for alcohol or drug use through immunoassay screening applied at hospital emergency units and their biological samples transferred to the Forensic Reference Laboratory (FRL) for confirmation analysis. The GC/HS-FID methodology was used to test Blood Alcohol Concentration (BAC). Qualitative and quantitative analyses for drugs were performed using the GC/MS or LC–MS/MS methodology.The BAC >0.5g/L was confirmed in 91.5% of drivers suspected for DUI cases and in 93% of DUID respectively. In DUI cases, results show an increasing incidence of road accidents involving drivers with BAC above 1.5g/L while at concentrations above 0.8g/L alcohol and drugs are both used. Among the suspected DUID cases, the intake of alcohol in association with drugs has consistently increased over time and positive results on blood samples was confirmed for multiple drugs (20%) or cannabis and cocaine alone (18%) followed by benzodiazepines (6%) and methadone (3.5%) respectively. The majority of injured drivers suspected for DUID (1017 cases) did not authorize blood sampling, therefore only urine was analyzed showing the prevalent use of cannabis, followed by multiple drug>cocaine>benzodiazepines>opiates.Among 1797 drivers, suspected at screening for DUI or DUID, 15.4% of cases (64 blood and 213 urine samples) were not confirmed by GC/HS, GC/MS or LC–MS/MS analysis. In forensic toxicological investigations, it is mandatory to satisfy the best quality standards, which is not achievable if immunochemical screening is only performed on urine. Therefore, only confirmed positive results of alcohol or drugs on blood samples can represent conclusive evidence to demonstrate the DUI or DUID related offences. An improvement of the protocols currently applied in Italy for the assessment of DUI or DUID crimes is needed and the confirmation analysis on blood should be considered mandatory.