1. Marijuana Involvement in Fatal Crashes
Staci Hoff, PhD
Research Director
(360)

2. Background
Legalized marijuana for recreational use through the passage of I-502 in Nov. 2012
Recreational stores began opening in July 2014
Portion of taxes from sales allocated to education and prevention
No prevention funds prior to sales
No funds allocated to traffic safety specifically
I-502 set a 5ng/ml blood per se marijuana limit

3. The Requests Poured In…

4. The Problem with Data Delta 9 Hashish Oil Hashish Marijuana/Marihuana
Marinol
Tetrahydrocannabinols (THC)
Cannabinoid (Type Unk)

5. Marijuana Has Always Been the Dominate Drug in Fatal Crashes

6. Does Marijuana Use Increase Crash Risk??

7. Toxicology Testing Among Persons Involved in Fatal Crashes
RCW – blood samples from all drivers/pedestrians killed in any traffic crash where death occurred within 4 hrs
Centralized Toxicology – all blood samples sent to the State Toxicologist at the Washington State Patrol Toxicology Lab

8. WTSC-RADD
Reviewed all toxicology paper reports (deceased) and manually entered full toxicology outcomes into spreadsheet
Worked with the Toxicology Lab to abstract the information for surviving drivers
Abstracted full toxicology for everyone in fatal crashes who had toxicology testing (drivers, occupants, non-motorists)
Married to the original FARS record for in-depth fatal crash analysis – state case number, MDE vehicle and person numbers
Initial report focused on data years , DRIVERS (

10. +24 in 2015 = 80 total drivers with THC ONLY

11. THC + Drugs + Alcohol <.079 2
Toxicology Outcomes
2010
2011
2012
2013
2014
*2015pre
Not Tested
219
226
224
212
272
375
No Drugs, No Alcohol
147
151
116
155
Alcohol Only <.079 15 8 6 7 10
Alcohol Only >.080 67 60 69 51 47
THC Only 9 13 20 24
Carboxy-THC Only 11 3 4
THC + Alcohol <.079 1 5
THC + Alcohol >.080 16 12 23 26
Carboxy-THC + Alcohol
THC + Drugs + Alcohol <.079 2
THC + Drugs + Alcohol >.080
Carboxy-THC + Drugs + Alcohol
THC + Drugs 17
Carboxy-THC + Drugs
Other Drugs Only 42 46 71 52 77
Other Drugs + Alcohol Only 18 19

13. Number of Units Involved

14. Day versus Night Crashes

15. Co-Occurring High Risk Factors

16. Unrestrained Drivers

17. THC versus Carboxy-THC and per se
Marijuana Result
2010
2011
2012
2013
2014
2015
Any Cannabinoid 81 56 63 59 89 94
THC >5 ng/ml 24 19 23 38 43
29.6%
33.9%
36.5%
32.2%
42.7%
45.7%
THC <5 ng/ml 12 13 18 37 36
14.8%
23.2%
19.0%
30.5%
41.6%
38.3%
THC Result Unk 1 6
Any Delta-9 THC 32 75 85
44.4%
57.1%
64.4%
84.3%
90.4%
Carboxy-THC 45 27 21 14 9
55.6%
42.9%
35.6%
15.7%
9.6%

18. What’s Next?
Continue to manually extract results and levels for fatal crashes
Integrated Traffic Records (TRCC)
Agreement between WTSC-WSP for electronic toxicology data files for record linkage – in process
Link drug testing outcomes to all crash severities
Data Governance is Important!
Data Users – AAA, IIHS, WSU, WSIPP
Challenges remain
Route/type of marijuana consumption
Blood level ^= Impairment
Chronic vs Acute Users

19. What can you do to prepare?
Are drivers being tested?
State law? Alcohol only?
WHO is testing them?
DUI/DRE database?
Blood warrants?
Hospital records?
WHICH labs are processing the samples?
Data Sharing Agreements!
Marijuana is NOT Alcohol, but Marijuana+Alcohol= REALLY SCARY!

20. Questions?