Discussion of Impaired Riding: Past Research and Implications for the Future Scott McKnight Pacific Institute for Research and Evaluation SMSA, Thursday, October 8, 2015

Outline Motorcycle Crashes and Alcohol Impaired Riding Research Methodologies Survey Research Discussion 2

Motorcycle Crashes and Alcohol In FARS, BACs >.08 a higher proportion of MC crashes than for any other vehicle type. Proportions of fatal crashes involving alcohol by vehicle type. (27% vs. 23% in 2012 ) 3

Lower BACs (>0, <.08%) Historically, the difference in proportions of lower BACs in FARS is greater between MCs and other vehicle types 2005: 7% for MCs and 4% for passenger vehicles Possible reasons: – Riders get into trouble at lower BACs – MCs more likely to result in fatalities > BACs more closely match general rider population > more riders than drivers at low BACs 4

Why are there higher proportions of alcohol involved in MC crashes than other for vehicles? Drinking and riding is riskier? More drinking riders? Both? How much does alcohol increase MC crash risk? 5

(2007)

Potential Methodologies Simulation – compare riders performance under a range of BACs Closed Course– compare riders performance under a range of BACs Case/Control study – identify MC crashes, find control riders same place/time, compare BACs Cohort Study – collect crash, near miss and BAC data from many riders in naturalistic setting over time 7

Potential Methodologies (cont.) Survey – self reported drinking, riding, near miss and crashes Compare FARS and injury crashes to Comparison data from: – Same location much later – Randomly selected roadside locations – Randomly selected fuel station locations 8

Closed Course 9

Creaser, J.I., Ward, N.J., Rakauskas, M.E., Boer, E., Shankwitz, C., Nardi, F. (2007) Instrumented vehicle with outriggers Relatively low-speed maneuvers (BRC, ERC) BACs =.00,.02,.05,.08 “…observable changes in motorcycle control and rider behavior in response to alcohol that are indicative of impairment.” “Most of the alcohol effects were evident at the per se BAC.08 g/dL level, but some of the effects were observed at the lower BAC.05.” 10

Creaser, et. al. (cont.) Strengths: – Highly controlled – Actual riding Limitations: – Off-street test rather than actual riding conditions – Minimizes effects of alcohol on judgement 11

Case/Control Hurt report, No BACs. Relied on police and researcher determination. No BAC MAIDS Study, 2009 – 5 European countries, 3 years, 921 crashes, using common research methodology. Relied on police and researcher determination. No BAC. Ongoing FHWA Crash Causation Study – low participation in voluntary breath sample for comparison riders. 12

Cohort Study Virginia Tech Transportation Institute Naturalistic Motorcycle Studies – Instrumented vehicles – MSF 100 data collection completed – NHTSA 160 data collection ongoing – No alcohol data collected 13

Compare crash data to data from randomly selected roadside locations National Roadside Survey (NRS) 2007 complete and published NRS 2013 unpublished Insufficient numbers of MCs to use as comparison data 14

NRS % of riders were operating at BACs of.08% or higher compared to 2.3% of passenger car drivers. Almost 14% of riders had BACs between.01 and.07 g/dL compared to 10% of passenger car drivers 15.4% of riders reported that “in the past 12 months, (they drove) after drinking enough that (they) might be considered to be legally under the influence of alcohol” compared to 12% for non-motorcyclists. 15

Conclusion Alcohol’s effects on crash risk not fully understood Alcohol continues to play a part in a higher proportion of MC crashes than for other vehicles. Why? – Alcohol adversely affects MC operation more? – More riders OUI? – Both? – Does it matter? 16

Discussion 17