Delays in blood collection and drug toxicology results among crash-involved drivers arrested for impaired driving.

OBJECTIVE: The concentration of drugs in a driver's system can change between an impaired driving arrest or crash and the collection of a biological specimen for drug testing. Accordingly, delays in specimen collection can result in the loss of critical information that has the potential to affect impaired driving prosecution. The objectives of the study were: (1) to identify factors that influence the time between impaired-driving violations and specimen collections (time-to-collection) among crash-involved drivers, and (2) to consider how such delays affect measured concentrations of drugs, particularly with respect to common drug per se limits. METHOD: Study data included blood toxicology results and crash-related information from 8,923 drivers who were involved in crashes and arrested for impaired driving in Wisconsin between 2019 and 2021. Analyses examined how crash timing and severity influenced time-to-collection and the effects of delays in specimen collection on blood alcohol concentrations (BACs) and blood delta-9-tetrahydrocannabinol (THC) concentrations. RESULTS: The mean time-to-collection for the entire sample was 1.80 h. Crash severity had a significant effect on time-to-collection with crashes involving a fatality having the longest duration (M = 2.35 h) followed by injury crashes (M = 2.06 h) and noninjury crashes (M = 1.69 h). Time of day also affected time-to-collection; late night and early morning hours were associated with shorter durations. Both BAC (r = -0.11) and blood THC concentrations (r = -0.16) were significantly negatively correlated with time-to-collection. CONCLUSIONS: Crash severity and the time of day at which a crash occurs can result in delays in the collection of blood specimens after impaired driving arrests. Because drugs often continue to be metabolized and eliminated between arrest and biological specimen collection, measured concentrations may not represent the concentrations of drugs that were present at the time of driving. This has the potential to affect drug-impaired driving prosecution, particularly in jurisdictions whose laws specify per se impairment thresholds.

Recommendations for Toxicological Investigation of Drug-Impaired Driving and Motor Vehicle Fatalities-2021 Update.

This report describes updates to the National Safety Council's Alcohol, Drugs and Impairment Division's recommendations for drug testing in driving under the influence of drug (DUID) cases and motor vehicle fatalities. The updates are based on a survey of drug testing practices in laboratories in the USA and Canada, a comprehensive review of the prior recommendations and data and research on drugs most frequently detected in DUID cases. A consensus meeting was held with representative forensic science practitioners and the authors of this report to update recommendations. No changes were made to the Tier I scope; however, there were changes to cutoffs of some analytes for blood, urine and oral fluid. Due to increased prevalence in DUID cases, trazodone and difluoroethane were added to the Tier II scope. For clarification, Tier I cutoffs reflect free concentrations, and hydrolysis is recommended but not required. The consensus panel concluded that urine is an inferior matrix to blood and oral fluid as it may represent historical use or exposure unrelated to observed impairment; therefore, future iterations of these recommendations will not include urine as a recommended matrix. Laboratories currently testing urine should work with traffic safety partners to encourage the use of blood and oral fluid as more appropriate specimens and adjust their capabilities to provide that testing.

Recommendations for Toxicological Investigation of Drug-Impaired Driving and Motor Vehicle Fatalities-2017 Update.

This report describes the outcomes of a process undertaken to review and update the National Safety Council's Alcohol, Drugs and Impairment Division's recommendations for the toxicological investigation of suspected alcohol and drug-impaired driving cases and motor vehicle fatalities. The updates to the recommendations are made based on a survey of practices in laboratories in the USA and Canada performing testing in these cases, consideration of existing epidemiological crash and arrest data, current drug use patterns, and practical considerations of widely available technology platforms in laboratories performing this work. The final recommendations updates are derived from a consensus meeting of experts recruited from survey respondents and the membership of the National Safety Council's Alcohol, Drug and Impairment Division. The principal changes in this round of recommendations include removal of butalbital, phenobarbital, and phencyclidine from Tier I (mandatory) to Tier II (optional) due to changes in prevalence. In addition, buprenorphine, fentanyl, tramadol, and their metabolites were moved from Tier II to Tier I due to increased prevalence and concerns about their potential for causing impairment. In addition, screening and confirmatory cutoffs for the oral fluid scope were further refined. Other additions were made to the list of Tier II compounds including fentanyl analogs (e.g., acetylfentanyl, butyrylfentanyl, furanylfentanyl, etc), mitragynine, novel opioids (e.g., MT-45, U-47700), atypical antipsychotics, and novel benzodiazepines (e.g., clonazolam, flubromazolam, etc).

Recommendations for toxicological investigation of drug-impaired driving and motor vehicle fatalities.

This report describes the review and update of a set of minimum recommendations for the toxicological investigation of suspected alcohol and drug-impaired driving cases and motor vehicle fatalities involving drugs or alcohol. The recommendations have the goal of ensuring that a consistent set of data regarding the most frequently encountered drugs linked to driving impairment is collected for practical application in the investigation of these cases and to allow epidemiological monitoring and the development of evidence-based public policy on this important public safety issue. The recommendations are based on a survey of practices in US laboratories performing this kind of analysis, consideration of existing epidemiological crash and arrest data and practical considerations of widely available technology platforms in laboratories performing this work. The final recommendations were derived from a consensus meeting of experts recruited from survey respondents and the membership of the National Safety Council's Alcohol, Drug and Impairment Division (formerly known as the Committee on Alcohol and Other Drugs, CAOD).