Table 1. Driver characteristics at the time of crash.
| Characteristic | Drivers deemed responsible for crash, count (%)n=434 119 | Drivers deemed non-responsible for crash, count (%)n=374 313 | Drivers with indeterminate responsibility, count (%)n=127 095 | P values, responsible vs non-responsible |
| Median age (Q1, Q3) (years) | 37 (23, 52) | 40 (28, 52) | 40 (27, 53) | <0.001 |
| Age categories | <0.001 | |||
| ≤20 years | 73 042 (16.8%) | 35 696 (9.5%) | 12 792 (10.1%) | |
| 21 to 44 years | 202 189 (46.6%) | 185 292 (49.5%) | 62 776 (49.4%) | |
| 45 to 64 years | 107 132 (24.7%) | 120 604 (32.2%) | 39 026 (30.7%) | |
| ≥65 years | 51 756 (11.9%) | 32 721 (8.7%) | 12 501 (9.8%) | |
| Male sex | 283 487 (65.3%) | 233 001 (62.2%) | 80 882 (63.6%) | <0.001 |
| Residential neighbourhood household income quintile | <0.001 | |||
| 1 (lowest income) | 82 859 (19.1%) | 67 265 (18%) | 23 573 (18.5%) | |
| 2 | 86 632 (20%) | 73 955 (19.8%) | 25 944 (20.4%) | |
| 3 | 85 237 (19.6%) | 74 453 (19.9%) | 25 207 (19.8%) | |
| 4 | 84 086 (19.4%) | 75 530 (20.2%) | 25 161 (19.8%) | |
| 5 (highest income) | 76 160 (17.5%) | 68 408 (18.3%) | 22 325 (17.6%) | |
| Missing | 19 145 (4.4%) | 14 702 (3.9%) | 4885 (3.8%) | |
| Rural residence | 210 543 (48.5%) | 178 512 (47.7%) | 51 953 (40.9%) | <0.001 |
| ≥1 hospitalisation in prior year | 49 490 (11.4%) | 39 527 (10.6%) | 13 416 (10.6%) | <0.001 |
| ≥7 physician visits in prior year | 20 649 (4.8%) | 14 320 (3.8%) | 5233 (4.1%) | <0.001 |
| Comorbidities | ||||
| Any psychiatric disorder | 25 516 (5.9%) | 17 747 (4.7%) | 6378 (5%) | <0.001 |
| Hypertension | 19 876 (4.6%) | 15 669 (4.2%) | 5515 (4.3%) | <0.001 |
| Alcohol use | 5065 (1.2%) | 2036 (0.5%) | 852 (0.7%) | <0.001 |
| Other drug use | 8117 (1.9%) | 3464 (0.9%) | 1512 (1.2%) | <0.001 |
| Diabetes | 7860 (1.8%) | 5438 (1.5%) | 2038 (1.6%) | <0.001 |
| Active prescriptions at baseline | <0.001 | |||
| 0 or 1 | 351 528 (81.0%) | 307 211 (82.1%) | 103 684 (81.6%) | |
| ≥2 | 82 591 (19.0%) | 67 102 (17.9%) | 23 411 (18.4%) | |
| Medications filled in prior 90 days | ||||
| Quetiapine | 3360 (0.8%) | 1759 (0.5%) | 733 (0.6%) | <0.001 |
| Risperidone | 1127 (0.3%) | 619 (0.2%) | 211 (0.2%) | <0.001 |
| Olanzapine | 660 (0.2%) | 278 (0.1%) | 128 (0.1%) | <0.001 |
| Aripiprazole | 233 (0.1%) | 168 (<0.1%) | 58 (<0.1%) | 0.086 |
| Clozapine | 36 (<0.1%) | 24 (<0.1%) | 5 (<0.1%) | 0.396 |
| Other antipsychotics | 904 (0.2%) | 455 (0.1%) | 189 (0.1%) | <0.001 |
| Benzodiazepines | 28 330 (6.5%) | 18 676 (5.0%) | 6925 (5.4%) | <0.001 |
| Opioids | 34 990 (8.1%) | 26 432 (7.1%) | 9268 (7.3%) | <0.001 |
| Driver licence type | <0.001 | |||
| Learner | 8047 (1.9%) | 2484 (0.7%) | 1213 (1.0%) | |
| Novice | 80 621 (18.6%) | 42 973 (11.5%) | 15 464 (12.2%) | |
| Full | 342 706 (78.9%) | 328 157 (87.7%) | 110 041 (86.6%) | |
| No license | 2745 (0.6%) | 699 (0.2%) | 377 (0.3%) | |
| Active license in prior 3 years | 429 365 (98.9%) | 372 921 (99.6%) | 126 374 (99.4%) | <0.001 |
| Median years with full license | 10.4 | 13.9 | 13.5 | <0.001 |
| Police-attended crash in prior 3 years | 48 207 (11.1%) | 34 783 (9.3%) | 12 340 (9.7%) | <0.001 |
| Any contravention in prior 3 years | 214 693 (49.5%) | 164 796 (44.0%) | 57 685 (45.4%) | <0.001 |
| Alcohol contravention | 34 356 (7.9%) | 16 415 (4.4%) | 6664 (5.2%) | <0.001 |
| Speed contravention | 133 427 (30.7%) | 105 679 (28.2%) | 36 151 (28.4%) | <0.001 |
| Distraction contravention | 6508 (1.5%) | 6165 (1.6%) | 2365 (1.9%) | <0.001 |
Our sample included 935 527 driver-crash combinations, of which 46% were deemed responsible for the crash and 2896 (0.31%) had a diagnosis of schizophrenia prior to the crash. Drivers with indeterminate responsibility were not included in analyses and are presented here for descriptive purposes only. Relative to non-responsible drivers, crash -responsible drivers were younger and more likely to have a novice driver’s license, recent medical visits for alcohol and other drug use, recent police-attended crashes, and recent traffic contraventions. The displayed p- values compare responsible drivers to non-responsible drivers. We note that the large sample size may produce p values <0.001 even in the absence of a clinically meaningful difference between groups.