Office of Research and Engineering, National Transportation Safety Board, Washington, District of Columbia.
Wisconsin State Laboratory of Hygiene, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
Traffic Inj Prev. 2024;25(5):667-672. doi: 10.1080/15389588.2024.2333918. Epub 2024 Apr 22.
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.
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.
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 = 2.35 h) followed by injury crashes = 2.06 h) and noninjury crashes = 1.69 h). Time of day also affected time-to-collection; late night and early morning hours were associated with shorter durations. Both BAC ( = -0.11) and blood THC concentrations ( = -0.16) were significantly negatively correlated with time-to-collection.
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.
驾驶员体内药物浓度会在因驾驶能力受损而被逮捕和采集生物样本进行毒理学检测之间发生变化。因此，样本采集的延迟可能会导致关键信息的丢失，而这些信息可能会影响对驾驶能力受损的起诉。本研究的目的是：（1）确定影响涉及撞车事故的驾驶员从驾驶能力受损到采集样本之间时间（采集时间）的因素；（2）考虑此类延迟对药物测量浓度的影响，特别是针对常见的药物法定限值。
研究数据包括来自威斯康星州的 8923 名在 2019 年至 2021 年间因撞车事故被捕的驾驶员的血液毒理学结果和与撞车事故相关的信息。分析考察了撞车时间和严重程度如何影响采集时间，以及样本采集延迟对血液酒精浓度（BAC）和血液 δ-9-四氢大麻酚（THC）浓度的影响。
整个样本的平均采集时间为 1.80 小时。撞车严重程度对采集时间有显著影响，涉及死亡的撞车事故持续时间最长（=2.35 小时），其次是受伤的撞车事故（=2.06 小时）和非受伤的撞车事故（=1.69 小时）。一天中的时间也影响采集时间；深夜和清晨的时间间隔较短。BAC（=−0.11）和血液 THC 浓度（=−0.16）与采集时间均呈显著负相关。
撞车严重程度和撞车发生时的时间可能导致在驾驶能力受损后对血液样本的采集延迟。由于在逮捕和生物样本采集之间，药物通常继续被代谢和消除，因此测量浓度可能无法代表驾驶时存在的药物浓度。这可能会影响对药物影响驾驶能力的起诉，特别是在那些规定法定损伤阈值的司法管辖区。
