Evaluation of Dräger DrugTest 5000 in a Naturalistic Setting

Complexity of Translating Analytics to Recent Cannabis Use and Impairment

While current analytical methodologies can readily identify cannabis use, definitively establishing recent use within the impairment window has proven to be far more complex, requiring a new approach. Recent studies have shown no direct relationship between impairment and Δ9-tetra-hydrocannabinol (Δ9-THC) concentrations in blood or saliva, making legal "per se" Δ9-THC limits scientifically unjustified. Current methods that focus on Δ9-THC and/or metabolite concentrations in blood, saliva, urine, or exhaled breath can lead to false-positive results for recent use due to the persistence of Δ9-THC well outside of the typical 3-4 h window of potential impairment following cannabis inhalation. There is also the issue of impairment due to other intoxicating substances-just because a subject exhibits signs of impairment and cannabis use is detected does not rule out the involvement of other drugs. Compounding the matter is the increasing popularity of hemp-derived cannabidiol (CBD) products following passage of the 2018 Farm Bill, which legalized industrial hemp in the United States. Many of these products contain varying levels of Δ9-THC, which can lead to false-positive tests for cannabis use. Furthermore, hemp-derived CBD is used to synthesize Δ8-THC, which possesses psychoactive properties similar to Δ9-THC and is surrounded by legal controversy. For accuracy, analytical methods must be able to distinguish the various THC isomers, which have identical masses and exhibit immunological cross-reactivity. A new testing approach has been developed based on exhaled breath and blood sampling that incorporates kinetic changes and the presence of key cannabinoids to detect recent cannabis use within the impairment window without the false-positive results seen with other methods. The complexity of determining recent cannabis use that may lead to impairment demands such a comprehensive method so that irresponsible users can be accurately detected without falsely accusing responsible users who may unjustly suffer harsh, life-changing consequences.

Detection of Δ9 -tetrahydrocannabinol (THC) in oral fluid using two point-of-collection testing devices following oral administration of a THC and cannabidiol containing oil

Point-of-collection testing (POCT) devices are widely used in roadside and workplace drug testing to identify recent cannabis use by measuring the presence of Δ9 -tetrahydrocannabinol (THC) in oral fluid (OF). However, the performance of POCT devices with oral medicinal cannabis products remains poorly described. In a randomised, double-blinded, crossover trial, adults with insomnia disorder (n = 20) received a single (2 mL) oral dose of oil containing 10 mg THC + 200 mg cannabidiol, or placebo, prior to sleep. Participants were tested with the Securetec DrugWipe® 5S (10 ng/mL THC cut-off) and Dräger DrugTest® 5000 (25 ng/mL THC cut-off) POCT devices at baseline (pre-treatment) and then at 0.5, 10, and 18 h post-treatment. An OF sample, taken at each time point, was also analysed using liquid chromatography-tandem mass spectrometry. Large individual variability in OF THC concentrations was observed 0.5 h post-treatment (range: 0-425 ng/mL; mean (SD) 48.7 (107.5) ng/mL). Both the Securetec DrugWipe® 5S and DrugTest® 5000 demonstrated poor sensitivity to THC at 0.5 h post-treatment (25% and 50%, respectively). At 10 and 18 h post-treatment, all participant OF THC concentrations were below screening cut-offs, and all test results were negative. These findings highlight the relatively poor sensitivity of both devices in detecting recent use of an oral medicinal cannabis product. They also suggest a low probability of obtaining a positive THC result the morning after ('one-off') use. Further research is required to establish the probability of obtaining a positive THC result with regular medicinal cannabis use.

Implementation of the first comprehensive state oral fluid drug testing program for roadside screening and laboratory testing in DUID cases-A 5-year review

Oral fluid (OF) is a valuable specimen for driving under the influence of drugs (DUID) applications. This study demonstrates the implementation of the first comprehensive OF drug testing program in the United States, including approved roadside screening OF devices for law enforcement and validated liquid chromatography-tandem mass spectrometry (LC-MS-MS) confirmation methods. Three roadside OF screening devices were evaluated: the Dräger DrugTest® 5000, Abbott SoToxa®, and Randox Evidence MultiSTAT™. Two qualitative LC-MS-MS confirmation methods were validated per ASB Standard 036. The first method utilized an automated dispersive pipette extraction extraction using Integra and Hamilton STARlet platforms for drugs of abuse. The second method used a liquid-liquid extraction to detect cannabinoids. The prevalence of drugs in blood and OF was monitored over 5 years of casework. Calibration curves were analyzed with each batch to monitor OF concentrations for research purposes. Three roadside OF screening devices were deemed fit for purpose. Devices demonstrated appropriate sensitivity, specificity, positive and negative predictive values, and accuracy above 80% for targeted drugs except for benzodiazepines (DrugTest® 5000) and amphetamine (SoToxa®). The validated LC-MS-MS OF confirmation methods met the National Safety Council-recommended cutoffs for 18/21 (86%) of the targets. Over 5 years of casework, THC and cocaine were detected at a positivity rate of 90% and 97% in OF versus 75% and 44% in blood, respectively. OF:blood ratios exceeded unity for parent drugs. Median concentrations of THC in OF and blood were 31 and 3.5 ng/mL, respectively. OF is a viable alternative or supplemental specimen for DUID investigations. Collecting OF close to the driving event increases the opportunity to identify pharmacologically active substances, and when combined with blood analysis results, an elevated OF:blood ratio provides valuable information for DUID investigation purposes.

Roadside screening tests for cannabis use: A systematic review

As more countries legalize recreational cannabis, roadside screening programs are imperative to detect and deter driving under the influence of cannabis. This systematic review evaluated roadside screening tests for cannabis use. We searched six databases (inception-March 2020) and grey literature sources for primary studies evaluating test characteristics of roadside screening tests for cannabis use compared to laboratory tests for cannabinoids in blood or oral fluid. The synthesis was focused on sensitivity and specificity of delta-9-tetrahydrocannabinol (THC) detection. 101 studies were included. Oral fluid tests were higher in specificity and lower in sensitivity compared to urine tests when evaluated against blood laboratory tests. Oral fluid tests were higher in sensitivity and similar in specificity compared to observational tests when evaluated against blood and oral fluid laboratory tests. Sensitivity was variable among oral fluid tests; two instrumented immunoassays (Draeger DrugTest 5000 [5 ng/mL THC cut-off] and Alere DDS 2 Mobile Test System) appeared to perform best, but definitive conclusions could not be drawn due to imprecise estimates. Specificities were similar. Overall, oral fluid tests showed the most promise for use in roadside screening for blood THC levels over legal limits; their continued development and testing are warranted. Urine tests are generally inadvisable, and observational tests require sensitivity improvements.

Effects of 3,4-methylenedioxymethamphetamine and methamphetamine on motor vehicle driving performance: A systematic review of experimental and observational studies

Methamphetamine (METH) and 3,4-methylenedioxymethamphetamine (MDMA) are common drugs of abuse and driving under their influence may occur in 1 million people yearly in the United States. This systematic review fills the currently unmet need in understanding the effects of METH and MDMA on motor vehicle driving performance (MVP) and provides insight into the forensic community. A PubMed search on September 24, 2020, for experimental and observational studies, which evaluated the impact of METH and MDMA on MVP was performed. After a review of 208 abstracts, 103 were considered potentially interesting and full texts were obtained. After the exclusion of non-English articles, review articles, single case reports, and articles which did not evaluate METH or MDMA on MVP, a total of nine experimental studies, 10 traditional observational studies, and 35 case series were included. The clinical rigor of experimental studies was evaluated using the Jadad scale. Experimental studies often demonstrated no significant MVP safety signals for METH or MDMA use, which was contrary to the overwhelming MVP safety risks found in observational studies. Common driving behaviors while using METH or MDMA include: errors in judgment, traveling at high speeds, failure to stop, merging inappropriately, lane weaving, and crashes. Limitations of experimental studies that led to dissimilar MVP outcomes from observational studies include: the common use of driving simulators, as opposed to actual driving examinations, and doses of METH or MDMA administered may not be representative of blood concentrations seen in observational studies. This systematic review has no funding source and was not registered.

Correlation between oral fluid and blood THC concentration: A systematic review and discussion of policy implications

Cannabis is the second most commonly used impairing substance by drivers, after alcohol. As more countries legalize cannabis, there is concern that cannabis-impaired driving will increase. In many countries, police use roadside devices to test for oral fluid THC (the primary psychotropic component in cannabis) to identify drivers who used cannabis; including in countries with non-zero per se limits for THC in blood. This practice is questioned as previous research demonstrates a poor correlation between oral fluid and blood THC concentrations at the individual level. We conducted a meta-analysis to identify all research that compared oral fluid with blood THC levels. We obtained individual-level data from study authors and analyzed pooled individual-level data to calculate sensitivity and specificity of oral fluid THC (at various cut-off values) to detect blood THC above different concentration limits. Finally, we explored practical implications of using oral fluid THC in an enforcement context. Our review found THC concentrations measured in over 18,000 paired samples of oral fluid and blood. We found a good correlation between the presence of THC in oral fluid and presence of THC in blood (sensitivity = 71.2%, specificity = 97.7%). However oral fluid THC, at commonly used cut-off values, is less sensitive and less specific when used as a biomarker to detect people with blood THC concentrations above commonly used per se limits (such as 5 ng/mL). As such, there will be a large number of "false positive" tests if oral fluid THC testing were used as a biomarker for "illegal" THC concentrations in randomly selected drivers. We argue that the adverse implications of false positive oral fluid THC tests in this context outweigh the possible road safety benefits and we recommend against oral fluid THC screening in randomly selected drivers in countries with non-zero per se limits for blood THC. In contrast, oral fluid THC tests appear to be useful for investigating "high-risk" drivers who come to police attention because of evidence of impairment.

A comprehensive breath test that confirms recent use of inhaled cannabis within the impairment window

Legalization of cannabis for medicinal and/or recreational use is expanding globally. Although cannabis is being regulated country by country, an accurate recent use test with indisputable results correlated with impairment has yet to be discovered. In the present study, a new approach for determining recent cannabis use within the impairment window after smoking was developed by studying 74 subjects with a mean age of 25 years and average use history of 9 years. Horizontal gaze nystagmus was evaluated along with subject self-assessments of impairment, and blood and breath samples were collected before and after smoking cannabis. Breath and blood pharmacokinetic parameters and cannabinoid profiles determined recent use within the impairment window. No subjects were positive for recent use pre-smoking, although all subjects had detectable cannabinoids in breath samples. We describe an inhaled cannabis recent use test that correlates with impairment and helps protect against wrongful prosecution and workplace discrimination.

Orally administered cannabidiol does not produce false-positive tests for Δ9 -tetrahydrocannabinol on the Securetec DrugWipe® 5S or Dräger DrugTest® 5000

Many jurisdictions use point‐of‐collection (POC) oral fluid testing devices to identify driving under the influence of cannabis, indexed by the presence of Δ⁹‐tetrahydrocannabinol (THC), an intoxicating cannabinoid, in oral fluid. Although the use of the non‐intoxicating cannabinoid, cannabidiol (CBD), is not prohibited among drivers, it is unclear whether these devices can reliably distinguish between CBD and THC, which have similar chemical structures. This study determined whether orally administered CBD produces false‐positive tests for THC on standard, POC oral fluid testing devices. In a randomised, double‐blind, crossover design, healthy participants (n = 17) completed four treatment sessions involving the administration of either placebo or 15‐, 300‐ or 1500‐mg pure CBD in a high‐fat dietary supplement. Oral fluid was sampled, and the DrugWipe®‐5S (DW‐5S; 10 ng·ml⁻¹ THC cut‐off) and Drug Test® 5000 (DT5000; 10 ng·mL⁻¹ THC cut‐off) devices administered, at baseline (pretreatment) and ~20‐, ~145‐ and ~185‐min posttreatment. Oral fluid cannabinoid concentrations were measured using ultra‐high performance liquid chromatography–tandem mass spectrometry. Median (interquartile range [IQR]) oral fluid CBD concentrations were highest at ~20 min, quantified as 0.4 (6.0), 15.8 (41.6) and 167 (233) ng·ml⁻¹ on the 15‐, 300‐ and 1500‐mg CBD treatments, respectively. THC, cannabinol and cannabigerol were not detected in any samples. A total of 259 DW‐5S and 256 DT5000 tests were successfully completed, and no THC‐positive tests were observed. Orally administered CBD does not appear to produce false‐positive (or true‐positive) tests for THC on the DW‐5S and DT5000. The likelihood of an individual who is using a CBD (only) oral formulation being falsely accused of DUIC therefore appears low.

Roadside Drug Testing Approaches

The purpose of this review is to present an overview of roadside drug testing, driving enforcement, and drunk/drug driving detection around the world. Drunk and drug driving is a severe problem, not only in the UAE, but also around the world. This has important implications for road safety as drunk or drug driving may increase the chances of a driver’s involvement in a road crash when compared to a drug-free driver. Recently, due to increases in drug-impaired drivers’ crash involvement, many mobile roadside drug testing devices have been introduced to the market. These devices use oral fluid, urine or blood matrices. These are on-the-spot tests, which are easy to use and are applied by law enforcement agencies and the public. Law enforcement agencies most commonly use oral fluid to detect the presence of illicit drugs in drivers. This review discusses all the available devices in the market used by the authorities. It also describes the type of drugs widely abused by drivers along with behavioral testing methods. The different types of matrices used for roadside drug testing are also evaluated. Sample collection, storage, and pre-treatment methods are discussed, followed by the confirmatory analysis of positive samples. This article will significantly help law enforcement agencies compare and evaluate all the reliable roadside testing devices and new emerging confirmatory devices available to them in the market. This will help them make an informed decision on which device to adapt to their individual needs.

Positivity to Cocaine and/or Benzoylecgonine in Confirmation Analyses for On-Road Tests in Spain

We are using real-life data in order to determine the prevalence of driving with the presence of cocaine and/or benzoylecgonine (BZE), their concentrations, and their use in combination with other drugs. This study assessed data on Spanish drivers with confirmed drug-positive results recorded by the Spanish National Traffic Agency from 2011-2016. Frequencies of positivity for cocaine and/or BZE and concentration of such substances were obtained. Comparisons and univariate and multivariate regression analyses were performed. Drivers who tested positive for cocaine and/or BZE accounted for 48.59% of the total positive results for drugs. In positive cases for both cocaine and BZE, other substances were detected in 81.74%: delta-9-tetrahydrocannabinol (THC) (68.19%), opioids (20.78%) and amphetamine-like substances (16.76%). In the multivariate logistic regression analysis, the frequency of cocaine and/or BZE positive cases decreased with age (OR:0.97) and were less likely among women (OR:0.63). Concentrations (ng/mL) of cocaine (249.30) and BZE (137.90) were higher when both substances were detected together than when detected alone. Positivity to cocaine represented an important proportion among Spanish drivers who tested positive for drugs, and polysubstance use was especially observed in more than 8 out of 10 positive cases for cocaine and/or BZE.

Interpol review of toxicology 2016-2019

This review paper covers the forensic-relevant literature in toxicology from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20.Papers%202019.pdf.

Topical review on monitoring tetrahydrocannabinol in breath

Legalization of cannabis for recreational use has compelled governments to seek new tools to accurately monitor Δ9-tetrahydrocannabinol (Δ9-THC) and understand its effect on impairment. Various methods have been employed to measure Δ9-THC, and its respective metabolites, in different biological matrices. Recently, breath analysis has gained interest as a non-invasive method for the detection of chemicals that are either produced as part of biological processes or are absorbed from the environment. Existing breath analyzers function by analyzing previously collected samples or by direct real-time analysis. Portable hand-held devices are of particular interest for law enforcement and personal use. This paper reviews and compares both commercially available and prototype devices that proclaim Δ9-THC detection in exhaled breath using methods such as Field Asymmetric Ion Mobility Spectrometry, Semiconductor-Enriched Single-Walled Carbon Nanotube chemiresistors, Liquid Chromatography Tandem-mass Spectrometry, microfluidic-based artificial olfaction, and optical-based gas sensing.

THC-influenced drivers in the new Danish 3-level offense system

Objective: The objectives of the study were to describe the distribution of tetrahydrocannabinol (THC)-influenced drivers in a new Danish 3-level offense system and discuss the consequences of the changed legislation.Methods: By request of the police, blood of individuals suspected of driving under the influence of drugs (DUID) in Funen and Southern Jutland was sampled by medical staff and shipped to the Section of Forensic Toxicology of the University of Southern Denmark in Odense. Samples from individuals suspected for driving under the influence of cannabis (DUIC) were stored at 5 °C prior to immediate analysis, and THC content in whole-blood samples was established by gas chromatography-mass spectrometry analysis. Quantitative results for blood THC levels were available from 2017 and 2018, resulting in 2,206 eligible cases. Data before and after the legal change on December 15, 2017, were extracted from the department's laboratory information management system.Results: With the new graduated sanctions introduced in December 2017, 70% of the DUIC suspects faced milder sanctions. The number of DUIC cases has been increasing and has almost doubled in the last 4 years, from 648 cases in 2015 to 1,206 in 2018. Correspondingly, the total number of DUID cases increased by 80% from 898 cases in 2015 to 1,614 cases in 2018. The concentration of THC in blood was above the legal limit of 0.001 mg/kg in 73% of the cases; 18% had concentrations categorized as low, 32% as medium, and 22% as high.Conclusion: We found that more than two-thirds of the THC offenders faced milder sanctions compared to before the new legislation, suggesting that the new graduated legislation has had a significant impact. The current trend is a steadily increasing number of DUID cases. We believe that the continual increase is caused by a combination of factors, including increased police awareness and training of police personnel along with improved roadside screening abilities.

Detection of Δ9 THC in oral fluid following vaporized cannabis with varied cannabidiol (CBD) content: An evaluation of two point-of-collection testing devices

Point‐of‐collection testing (POCT) for Δ⁹‐tetrahydrocannabinol (THC) in oral fluid is increasingly used to detect driving under the influence of cannabis (DUIC). However, previous studies have questioned the reliability and accuracy of two commonly used POCT devices, the Securetec DrugWipe^® 5 s (DW5s) and Dräger DrugTest^® 5000 (DT5000). In the current placebo controlled, double‐blind, crossover study we used liquid chromatography‐tandem mass spectrometry (LC–MS/MS) to accurately quantify cannabinoid concentrations in the oral fluid of 14 participants at various timepoints (10, 60, 120, and 180 minutes) following vaporization of 125 mg of THC‐dominant (11% THC; <1% CBD), THC/CBD equivalent (11% THC; 11% CBD) and placebo (<1% THC; <1% CBD) cannabis. At each timepoint, oral fluid was also screened using the DW5s (10 ng/mL THC cut‐off) and DT5000 (10 ng/mL THC cut‐off). LC–MS/MS analysis showed peak oral fluid THC concentrations at the 10 minute timepoint with a rapid decline thereafter. This trajectory did not differ with THC dominant and THC/CBD equivalent cannabis. With a 10 ng/mL confirmatory cut‐off, 5% of DW5s test results were false positives and 16% false negatives. For the DT5000, 10% of test results were false positives and 9% false negatives. Neither the DW5s nor the DT5000 demonstrated the recommended >80% sensitivity, specificity and accuracy. Accuracy was lowest at 60 minutes, when THC concentrations were often close to the screening cut‐off (10 ng/mL). POCT devices can be useful tools in detecting recent cannabis use; however, limitations should be noted, and confirmatory LC–MS/MS quantification of results is strongly advisable.

User experience and operational feasibility of four point-of-collection oral fluid drug-testing devices according to Brazilian traffic agents

OBJECTIVE

Traffic fatalities in Brazil still rank among the highest worldwide, with an overall rate of 23.4 deaths/100,000 inhabitants/year. Although alcohol and drug use play an important role in traffic accidents, national data about their relative influence are scarce. Drug screening is not routinely performed by traffic agents because alcohol is the only substance regularly investigated in roadblocks. Therefore, we aimed to describe the initial traffic agent user experience for 4 handheld point-of-collection oral fluid drug testing devices used in routine roadblocks in Brazil, focusing on usage perceptions in hopes of generalizing this approach for other developing countries.

METHODS

Four different oral fluid collection devices were evaluated: The DDS2, the DOA MultiScreen, the Dräger DrugTest 5000, and the Multi-Drug Multi-Line Twist Screen Device. Fourteen trained traffic agents obtained oral fluid from 164 drivers and performed 37 qualitative evaluations of the devices. Traffic agents filled out a questionnaire focusing on 9 feasibility criteria: Overall simplicity for roadside operation; operational success; saliva sample collection time; sample analysis time; ease of sample preparation and analysis; agreement with observed clinical signs; overall hygiene and safety; sufficient operating instructions; and hygiene of saliva collection. These were weighted based on an expert panel and yielded an overall composite device experience score that ranged from 1 (poor) to 100 (excellent).

RESULTS

Ease of use, operational success, and acceptable collection and analysis time were considered the most important criteria by the expert panel. The results ranged from 27.3 to 88.9% for simplicity of use; 45.5 to 100.0% for operational success; 27.3 to 100% for acceptable collection time; and 36.4 to 100.0% for acceptable analysis time. The final device scores, based on the agents' user experiences, ranked as follows: DOA MultiScreen: 49.3/100; Dräger DrugTest 5000: 82.4/100; Multi-Drug Multi-Line Twist Screen Device: 84.3/100; DDS2: 88.4/100.

CONCLUSION

Based on the selected criteria, 3 of the 4 devices were considered useful by traffic agents in routine roadblock operations. The weighted evaluations suggest that their ease of use (handling, sampling analysis, and reliability), as well as their agreement with findings obtained by other means, defined their utility to traffic agents, although such appraisals must be further analyzed in future studies.

Toxicological oral fluid results among Spanish drivers testing positive on on-site drug controls from 2013 to 2015

BACKGROUND

Driving under the influence of drugs (DUID) increases the risk of serious injury or death in traffic accidents. The aim of this study was to provide information about DUID in Spanish drivers.

METHODS

10,064 oral fluid samples were collected from Spanish drivers that tested positive on the roadside using the Dräger DrugTest 5000 (DDT5000) between 2013 and 2015. Samples were collected using Quantisal^™ and analysed by LC-MS/MS at the Toxicology Laboratory of the Institute of Forensic Science of the University of Santiago de Compostela.

RESULTS

Drivers were mainly young men (85.1% male, 29.7 ± 8.1 years old). In 98.5% of cases, LC-MS/MS results confirmed at least one of the positive results detected on the roadside. Cannabis (82.4%) and cocaine (42.1%) were the most commonly detected drugs. Poly-drug use was observed in 42.7% of drivers, mostly for all illicit drugs (>80%) except for cannabis (42.6%). Illicit drug and single-drug use was more frequent among drivers under 35 years old, and medicines and poly-drug use more common among drivers older than 35 years old. The on-site device performance was calculated using both the DDT5000 cut-offs and the LC-MS/MS method LOQs. Sensitivity (>73% vs >58%), specificity [>94% for all the compounds regardless the cut-offs used, except for cannabis (71%)] and accuracy (>87.5% with both cut-offs) fulfilled the DRUID Project requirements in all cases.

CONCLUSION

LC-MS/MS confirmation result was negative in only 1.5% of the cases. The DUID driver profile was a young man, consuming cannabis or a combination of cannabis and cocaine.

Roadside survey of alcohol and drug use among Norwegian drivers in 2016-2017: A follow-up of the 2008-2009 survey

OBJECTIVE

The objective of this study was to study the use of alcohol and drugs among the general driving population in the southeastern part of Norway and to compare the findings with the results from a similar roadside survey in 2008-2009.

METHODS

A roadside survey of drivers of cars, vans, motorcycles, and mopeds was performed from April 2016 to April 2017 in collaboration with the Mobile Police Service. Oral fluid was collected using the Quantisal device and analyzed for alcohol, illicit drugs, and psychoactive medicinal drugs. Age, sex, time, and geographical region were recorded.

RESULTS

Of the 5,556 drivers who were asked to participate in the study, 518 drivers (9.3%) declined to participate, and 4 samples contained insufficient volume of oral fluid to be analyzed; thus, 5,034 drivers were included. Fifteen drivers (0.3%) suspected by the police for driving under the influence of alcohol or drugs refused to participate in the study, so the alcohol and drug findings represent minimum values. The weighted prevalence of alcohol concentrations above the legal limit of 0.2 g/L was 0.2%, which is similar to the finding in the 2008-2009 survey. The weighted prevalences of medicinal drugs and illicit drugs were 3.0 and 1.7%, respectively; those numbers included more drugs than the 2008-2009 survey and are therefore not comparable. The most prevalent illicit and medicinal drugs were tetrahydrocannabinol (1.3%) and zopiclone (1.4%). The prevalences of benzodiazepines and amphetamines were significantly lower than detected in the 2008-2009 survey. Only one sample tested positive for a new psychoactive substance.

CONCLUSIONS

The proportion of samples that tested positive for alcohol had not changed since 2008-2009, and the proportions that tested positive for benzodiazepines and amphetamines were lower. There are several possible reasons for the reduction: Implementation of legal limits for 28 drugs in 2012-2016, increased use of drug recognition tests, implementation of drug screening instruments, and automatic number plate recognition by the police since 2010; more focused enforcement of the driving under the influence (DUI) law; better information provided to drivers; and changes in drug prescriptions.