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Table 1 Population characteristics for teen driver participants in the National Roadside Survey (NRS), 2013–2014

From: Marijuana use in U.S. teen drivers: a comparison of a road-side survey of reported use and fluid tests for tetrahydrocannabinol (THC)

  THC Test Results (Oral Fluid and/or Blood)a  
  Negative Test (all means) Positive Test (any means)b Total1  
  n (%)   Chi Square (p-value)
Total (n) 575 91 718  
Demographic Characteristics
 Age (yrs)     0.02
  16–17 132 (23.0) 11 (12.1) 154 (21.5)  
  18–19 443 (77.0) 80 (87.9) 564 (78.6)  
 Gender     0.04
  Male 349 (61.0) 65 (72.2) 446 (62.5)  
  Female 223 (39.0) 25 (27.8) 268 (37.5)  
 Race/Ethnicity     0.28
  White, Non-Hispanic 416 (72.4) 69 (75.8) 523 (72.8)  
  Black, Non-Hispanic 70 (12.2) 15 (16.5) 91 (12.7)  
  Hispanic 64 (11.1) NR 77 (10.7)  
  Asian, Non-Hispanic NR NR 19 (2.7)  
  More than one/Other NR NR NR  
 Region     0.45
  South 147 (25.6) 19 (20.9) 182 (25.4)  
  Northeast 80 (13.9) 17 (18.7) 108 (15.0)  
  Midwest 181 (31.5) 32 (35.2) 223 (31.1)  
  West 167 (29.0) 23 (25.3) 205 (28.6)  
 Education level     0.025
  Less than high school 187 (26.0) 18 (19.8) 174 (26.1)  
  High school graduate 176 (30.6) 42 (46.2) 237 (33.0)  
  College 235 (40.9) 29 (31.9) 281 (39.1)  
  Other/Unknown NR NR 11 (1.5)  
 Vocational status     0.003
  Employed, full time 126 (21.9) 34 (37.3) 175 (24.4)  
  Employed, part time 283 (49.2) 38 (41.8) 344 (47.9)  
  Not employed, student 89 (15.5) NR 101 (14.1)  
  Unemployed, not student 23 (4.0) NR 33 (4.6)  
  Other 54 (9.4) NR 65 (8.9)  
 Household income     0.004
  0 < $25,000 170 (29.6) 41 (45.1) 232 (32.4)  
  $25,001 < $50,000 117 (20.4) 20 (22.0) 145 (20.2)  
  $50,001 < $75,000 84 (14.6) 12 (13.2) 102 (14.2)  
  $75,001 < $100,000 NR NR 75 (10.5)  
  $100,001 or more 77 (13.4) 13 (14.3) 93 (13.0)  
  Did not answer 57 (9.9) NR 70 (9.8)  
 Time of year     0.0004
  June to August 196 (34.1) 14 (15.4) 210 (31.5)  
  September to March 379 (65.9) 77 (84.6) 456 (68.5)  
 State Medical Marijuana Law (MML) characteristics     0.03
  States without MMLs 379 (65.9) 63 (69.2) 474 (66.0)  
  States with MMLs & state-regulated dispensary 75 (13.0) 18 (19.8) 106 (14.8)  
  States with MMLs plus leniency provisions 121 (21.0) NR 138 (19.2)  
 Seatbeltc     0.40
  Lap and shoulder 530 (92.1) 82 (90.1) 662 (92.2)  
  Other, belted 40 (7.0) NR 51 (7.1)  
  Not belted NR NR NR  
 Passengers (Y,N)     0.009
  Absent 293 (51.0) 33 (36.3) 352 (49.0)  
  Present 282 (49.0) 58 (63.7) 366 (51.0)  
  1. aOral and blood THC tests were missing for 52 study participants who completed the survey
  2. bOral THC values have a cutoff value of 2 ng/mL & blood THC values have a cutoff value of 1 ng/mL (Kelley-Baker, et.al 2017)
  3. cFisher’s exact test generated p-values; NR Not reported due to small numbers