title: The Impact of Michigan's Partial Repeal of the Universal Motorcycle Helmet Law on Helmet Use, Fatalities, and Head Injuries.
abstract: To evaluate the impact of the partial repeal of Michigan's universal motorcycle helmet law on helmet use, fatalities, and head injuries.
  
  
  
  We compared helmet use rates and motorcycle crash fatality risk for the 12 months before and after the April 13, 2012, repeal with a statewide police-reported crash data set. We linked police-reported crashes to injured riders in a statewide trauma registry. We compared head injury before and after the repeal. Regression examined the effect of helmet use on fatality and head injury risk.
  
  
  
  Helmet use decreased in crash (93.2% vs 70.8%; P < .001) and trauma data (91.1% vs 66.2%; P < .001) after the repeal. Although fatalities did not change overall (3.3% vs 3.2%; P = .87), head injuries (43.4% vs 49.6%; P < .05) and neurosurgical intervention increased (3.7% vs 6.5%; P < .05). Male gender (adjusted odds ratio [AOR] = 1.65), helmet nonuse (AOR = 1.84), alcohol intoxication (AOR = 11.31), intersection crashes (AOR = 1.62), and crashes at higher speed limits (AOR = 1.04) increased fatality risk. Helmet nonuse (AOR = 2.31) and alcohol intoxication (AOR = 2.81) increased odds of head injury.
  
  
  
  Michigan's helmet law repeal resulted in a 24% to 27% helmet use decline among riders in crashes and a 14% increase in head injury.
authors.affiliation: Patrick M. Carter is with the Injury Center, School of Medicine, University of Michigan, Ann Arbor. Lisa Buckley, Carol A. C. Flannagan, Patrick J. Bowman, Farideh Almani, and C. Raymond Bingham are with the Transportation Research Institute, University of Michigan. Jessica B. Cicchino is with Insurance Institute for Highway Safety, Arlington, VA. Mark Hemmila is with the Division of Acute Care Surgery, Department of Surgery, School of Medicine, University of Michigan.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Carter
authors.affiliation: Patrick M. Carter is with the Injury Center, School of Medicine, University of Michigan, Ann Arbor. Lisa Buckley, Carol A. C. Flannagan, Patrick J. Bowman, Farideh Almani, and C. Raymond Bingham are with the Transportation Research Institute, University of Michigan. Jessica B. Cicchino is with Insurance Institute for Highway Safety, Arlington, VA. Mark Hemmila is with the Division of Acute Care Surgery, Department of Surgery, School of Medicine, University of Michigan.
authors.forename: Lisa
authors.initials: L
authors.lastname: Buckley
authors.affiliation: Patrick M. Carter is with the Injury Center, School of Medicine, University of Michigan, Ann Arbor. Lisa Buckley, Carol A. C. Flannagan, Patrick J. Bowman, Farideh Almani, and C. Raymond Bingham are with the Transportation Research Institute, University of Michigan. Jessica B. Cicchino is with Insurance Institute for Highway Safety, Arlington, VA. Mark Hemmila is with the Division of Acute Care Surgery, Department of Surgery, School of Medicine, University of Michigan.
authors.forename: Carol A C
authors.initials: CA
authors.lastname: Flannagan
authors.affiliation: Patrick M. Carter is with the Injury Center, School of Medicine, University of Michigan, Ann Arbor. Lisa Buckley, Carol A. C. Flannagan, Patrick J. Bowman, Farideh Almani, and C. Raymond Bingham are with the Transportation Research Institute, University of Michigan. Jessica B. Cicchino is with Insurance Institute for Highway Safety, Arlington, VA. Mark Hemmila is with the Division of Acute Care Surgery, Department of Surgery, School of Medicine, University of Michigan.
authors.forename: Jessica B
authors.initials: JB
authors.lastname: Cicchino
authors.affiliation: Patrick M. Carter is with the Injury Center, School of Medicine, University of Michigan, Ann Arbor. Lisa Buckley, Carol A. C. Flannagan, Patrick J. Bowman, Farideh Almani, and C. Raymond Bingham are with the Transportation Research Institute, University of Michigan. Jessica B. Cicchino is with Insurance Institute for Highway Safety, Arlington, VA. Mark Hemmila is with the Division of Acute Care Surgery, Department of Surgery, School of Medicine, University of Michigan.
authors.forename: Mark
authors.initials: M
authors.lastname: Hemmila
authors.affiliation: Patrick M. Carter is with the Injury Center, School of Medicine, University of Michigan, Ann Arbor. Lisa Buckley, Carol A. C. Flannagan, Patrick J. Bowman, Farideh Almani, and C. Raymond Bingham are with the Transportation Research Institute, University of Michigan. Jessica B. Cicchino is with Insurance Institute for Highway Safety, Arlington, VA. Mark Hemmila is with the Division of Acute Care Surgery, Department of Surgery, School of Medicine, University of Michigan.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Bowman
authors.affiliation: Patrick M. Carter is with the Injury Center, School of Medicine, University of Michigan, Ann Arbor. Lisa Buckley, Carol A. C. Flannagan, Patrick J. Bowman, Farideh Almani, and C. Raymond Bingham are with the Transportation Research Institute, University of Michigan. Jessica B. Cicchino is with Insurance Institute for Highway Safety, Arlington, VA. Mark Hemmila is with the Division of Acute Care Surgery, Department of Surgery, School of Medicine, University of Michigan.
authors.forename: Farideh
authors.initials: F
authors.lastname: Almani
authors.affiliation: Patrick M. Carter is with the Injury Center, School of Medicine, University of Michigan, Ann Arbor. Lisa Buckley, Carol A. C. Flannagan, Patrick J. Bowman, Farideh Almani, and C. Raymond Bingham are with the Transportation Research Institute, University of Michigan. Jessica B. Cicchino is with Insurance Institute for Highway Safety, Arlington, VA. Mark Hemmila is with the Division of Acute Care Surgery, Department of Surgery, School of Medicine, University of Michigan.
authors.forename: C Raymond
authors.initials: CR
authors.lastname: Bingham
mesh_terms: D000063:Accidents, Traffic / Q000401:mortality / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D006259:Craniocerebral Trauma / Q000453:epidemiology* / Q000401:mortality; D005260:Female; D006260:Head Protective Devices / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008875:Middle Aged; D009049:Motorcycles / Q000331:legislation & jurisprudence*; D012189:Retrospective Studies