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Table 1 Description of the study population by motorcycle helmet law

From: Motorcycle helmet effectiveness in reducing head, face and brain injuries by state and helmet law

Characteristic Partial helmet law Universal helmet law P-value*
Number of motorcycle operators N = 28,207 N = 45,552  
Helmet used 42 % 88 % <0.01
Age (Median) 37 36 0.52
Male 93 % 93 % 0.77
Single Vehicle Crash 39 % 45 % <0.01
Crash at Intersection 36 % 40 % <0.01
Night time 18 % 17 % <0.01
Speed relateda 10 % 17 % <0.01
Suspicion of alcohol or drugsa 9 % 5 % <0.01
Rural locationa 17 % 31 % <0.01
Poor Surface Conditions 6 % 7 % <0.01
Crash record linked to a medical record 55 % 58 % <0.01
Died at the scene 3 % 3 % 0.62
  1. a Available for only a subset of the 11 included states: speed related (10), suspicion of alcohol or drugs (9), and rural location (8)
  2. *P-value from a Median regression model with bootstrapped standard error (age), or likelihood ratio test of homogeneity (all others)