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National Highway Traffic Safety Administration NHTSA Research on Impaired Driving Heidi Coleman Chief, Behavioral Research NHTSA Office of Behavioral Safety.

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Presentation on theme: "National Highway Traffic Safety Administration NHTSA Research on Impaired Driving Heidi Coleman Chief, Behavioral Research NHTSA Office of Behavioral Safety."— Presentation transcript:

1 National Highway Traffic Safety Administration NHTSA Research on Impaired Driving Heidi Coleman Chief, Behavioral Research NHTSA Office of Behavioral Safety Research

2 Safer Drivers. Safer Cars. Safer Roads. The prevalence of impaired driving – National Roadside Surveys; Washington Roadside Survey Impairment due to the use of alcohol and other drugs – Inhaled Cannabis Study The crash risk of impaired driving – Crash Risk Study Strategies to reduce impaired driving – Laws and Policies – Law Enforcement and Criminal Justice Strategies – Assessment, Monitoring and Treatment – Prevention, Communication and Outreach Impaired Driving Research – Key Questions

3 Safer Drivers. Safer Cars. Safer Roads. National Roadside Survey (NRS) Research Note published February 2015 Full report (3 volumes) in review  Methodology  Alcohol Results  Drug Results Hope to publish reports in 2015

4 Safer Drivers. Safer Cars. Safer Roads. Four decades of National Roadside Surveys – 1973, 1986, 1996 (alcohol only) – 2007, 2013-2014 (included also drugs) Well developed methodology – Nationally-representative sample of drivers – Reviewed and approved by Institutional Review Board – Voluntary and anonymous – About 10,000 drivers in 300 locations across the nation Nighttime weekend sample – Daytime comparison NRS - Overview

5 Safer Drivers. Safer Cars. Safer Roads. 60 sites across the country, representing the U.S. Five “shifts” each weekend; five locations at each site: – Fridays 9:30 am – 11:30 am or 1:30 pm – 3:30 pm 10:00 pm – midnight 1:00 am – 3:00 am – Saturdays 10:00 pm – midnight 1:00 am – 3:00 am NRS - Data Collection

6 Safer Drivers. Safer Cars. Safer Roads. Drivers guided to survey bay Breath Test (PBT) Alcohol Use Disorder (AUD) questions Drug use questions Oral fluid collection with Quantisal device ($10) Blood sample collection by phlebotomist ($50) NRS - Procedure

7 Safer Drivers. Safer Cars. Safer Roads. NRS - Team Sets Up

8 Safer Drivers. Safer Cars. Safer Roads. NRS - As Drivers Approach

9 Safer Drivers. Safer Cars. Safer Roads. NRS - First Thing Drivers See

10 Safer Drivers. Safer Cars. Safer Roads. NRS - Data Collection Underway

11 Safer Drivers. Safer Cars. Safer Roads. NRS - Data Collection (continued)

12 Safer Drivers. Safer Cars. Safer Roads. NRS - We’re Ready for Every Situation

13 Safer Drivers. Safer Cars. Safer Roads. NRS 2013-2014 – Participation Number of Participants and Participation Rates in the 2013-2014 NRS Drivers Participants N % Eligible and Entered Site 11,100 100.0% Breath Test 9,455 85.2% Oral Fluid Test 7,881 71.0% Blood Test 4,686 42.2% Oral Fluid and/or Blood 7,898 71.2%

14 Safer Drivers. Safer Cars. Safer Roads. NRS 2013-2014 – Alcohol Results Percentage of Weekend Nighttime Drivers by BrAC Category in the Five National Roadside Surveys

15 Safer Drivers. Safer Cars. Safer Roads. Data Collection Time Period % Alcohol Positive (%BrAC > 0.005) % BrAC > 0.08 Friday Daytime 1.1%0.4% Friday and Saturday Nighttime 8.3%1.5% NRS 2013-2014 – Alcohol Results Alcohol Prevalence by Data Collection Period and BrAC in the 2013–2014 NRS

16 Safer Drivers. Safer Cars. Safer Roads. NRS 2013-2014 – Drug Results Overall Drug Prevalence by Data Collection Period and Type of Test in the 2013–2014 NRS Time of Day % Drug-Positive Oral Fluid Test % Drug- Positive Blood Test % Drug-Positive Oral Fluid and/or Blood Test Weekday Daytime 19.0%21.6%22.4% Weekend Nighttime 19.8%21.2%22.5% Drug-positive = over-the-counter, prescription, and illegal. Presence does not equal impairment.

17 Safer Drivers. Safer Cars. Safer Roads. NRS 2013-2014 – THC Results Weekend Nighttime Prevalence of THC in 2007 Compared to 2013-2014 Comparable Data 20072013-2014 Comparable Data Oral Fluid Test Blood Test Oral Fluid and/or Blood Test Oral Fluid Test Blood Test Oral Fluid and/or Blood Test N % 438 7.7%234 7.6%499 8.6%597 11.3%332 11.7% 663 12.6%

18 Safer Drivers. Safer Cars. Safer Roads. Summary of NRS 2013-2014 Results Alcohol use by drivers continues to decline – Decrease by more than three-quarters since 1973 – Decrease by nearly one-third since 2007 – Policies and programs appear to be working Drug use increasing – Prescription and over-the-counter use up slightly – Illegal use up significantly – Marijuana use up by nearly 50% since 2007

19 Safer Drivers. Safer Cars. Safer Roads. Crash Risk Study Research Note published February 2015 Full report in review Hope to publish report in 2015

20 Safer Drivers. Safer Cars. Safer Roads. Previous studies to estimate Crash Risk of Alcohol – Borkenstein (1974); NHTSA (Blomberg, 2005) Sought to estimate Crash Risk of Alcohol and Drugs “Case-control” methodology – Comparison of an experimental case (driver in a crash) to a comparison control case (driver not in a crash) – Trusted methodology; precise design; expensive and time- consuming – In a site where enforcement, hospitals, local gov’t, etc. would fully cooperate and participate – Virginia Beach, VA Crash Risk Study - Background

21 Safer Drivers. Safer Cars. Safer Roads. Sample size of 3,000 crash-involved drivers Sample size of 6,000 control drivers Matched as best we can based on – – Same stretch of road, direction of traffic – Same day of week, time of day Perfect? No. Most carefully designed study to date? YES. Crash Risk Study - Study Design

22 Safer Drivers. Safer Cars. Safer Roads. When a crash was reported…. – Research Team responded Team = Virginia Beach Police Office; PIRE Researcher/Phlebotomist – Once scene secured and everyone safe, Officer asked the driver if they would be willing to talk to a Researcher If yes – study began If no – thanks anyway Like NRS, the study was: – Voluntary, anonymous, driver can choose to stop at any time Returned the following week for control drivers Crash Risk Study - Protocol

23 Safer Drivers. Safer Cars. Safer Roads. For both crash-involved drivers and control drivers: Asked questions about drinking, driving, drinking and driving, and drug use Asked drivers to provide: – Breath sample – Oral fluid sample ($10) – Blood sample ($50) Statistical analysis used to match crash to control cases Crash Risk Study – Protocol (cont)

24 Safer Drivers. Safer Cars. Safer Roads. Crash Risk Study

25 Safer Drivers. Safer Cars. Safer Roads.

26 Study continues

27 Safer Drivers. Safer Cars. Safer Roads. Crash Risk Study - Participation CrashControl Eligible Drivers3,8877,397 Agreed to Participate3,682 (94.7%)7,176 (97.0%) Breath sample3,393 (87.3%)7,079 (95.7%) Oral Fluid or Blood3,196 (82.2%)6,935 (93.8%)

28 Safer Drivers. Safer Cars. Safer Roads. Crash Risk Study Results – Alcohol Crash Risk Alcohol Crash Risk Adjusted for Age and Gender

29 Safer Drivers. Safer Cars. Safer Roads. Crash Risk Study Results – Drug Crash Risk Significant findings (p value ≤.01) for two types of drugs – THC (marijuana) – Illegal drugs Drug of Interest Unadjusted Odds Ratio P Value THC (Marijuana)1.250.01 Sedatives1.300.06 Narcotic Analgesics1.150.26 Antidepressants1.060.75 Stimulants1.010.40 Illegal Drugs1.210.01 Legal Drugs1.070.43 Unadjusted Odds Ratios between Drug Class Use and Crash Risk

30 Safer Drivers. Safer Cars. Safer Roads. Crash Risk Study Results – Drug Crash Risk Drug of Interest Adjusted Odds Ratio 95% CI* P Value THC (Marijuana)1.050.86 – 1.270.65 Antidepressants0.870.57 – 1.320.51 Narcotic Analgesics 1.140.85 – 1.510.39 Sedatives1.270.93 – 1.750.13 Stimulants0.940.72 – 1.220.64 Illegal Drugs1.040.88 – 1.230.65 Legal Drugs1.030.84 – 1.270.79 Adjusted Odds Ratios between Drug Class Use and Crash Risk (adjusted for demographics, e.g., age, gender) When adjusted for factors that we know are associated with crash risk (e.g., age, gender) No significant findings Age/gender accounted for elevated THC and illegal drug risk

31 Safer Drivers. Safer Cars. Safer Roads. Study confirms elevated risk based on alcohol Study does not demonstrate elevated risk based on drugs Consistent with previous well controlled studies However, study does not indicate that drug use by drivers is risk-free In some situations, drugs (other than alcohol) can seriously impair driving ability and increase crash risk Due to increased prevalence of drugs (NRS), further monitoring and research is warranted Crash Risk Study - Summary

32 Safer Drivers. Safer Cars. Safer Roads. Examine the Effects of Inhaled Cannabis on Driving Performance Expert Panel on Impact of Legalizing Marijuana on the DWI System (NCREP project) Washington State – Roadside Survey of Alcohol and Drugs (THC) Evaluation of Oral Fluid Drug Testing Devices (Allere; Drager) Evaluation of the Advanced Roadside Impairment Driving Enforcement (ARIDE) Curriculum Other Drugged Driving Research

33 Safer Drivers. Safer Cars. Safer Roads. DWI Court Survey (ongoing) Feasibility of Ignition Interlocks on Motorcycles (pending agency review) Use of Interlock Data (pending agency review) Feasibility of Voluntary Interlock Program for Teens (pending agency review) Evaluation of SCRAM (Secure Continuous Remote Alcohol Monitoring device) (published April 2015) Evaluation of Washington State Target Zero Teams (published January 2015) Other Alcohol-Impaired Driving Research

34 Safer Drivers. Safer Cars. Safer Roads. Other Research Published Nov 2014 Important Note of Caution Now distributed with requests for FARS drugged driving data

35 Safer Drivers. Safer Cars. Safer Roads. Thank you Questions? Heidi.Coleman@dot.gov


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