Table 4.
Predictors of injury crashes among 14- and 15-year-old drivers involved in motor vehicle crashes, Iowa, 2001–2013 (n = 8,466).
| Characteristic | Total injury crashes n (%) |
Univariable analysis |
Multivariable model |
||
|---|---|---|---|---|---|
| Crude ORa |
95% CI | Adjusted ORa | 95% CI | ||
| Driver age | |||||
| 14 years old | 376 (21%) | REF. | REF. | ||
| 15 years old | 1,448 (79%) | 0.85 | (0.75, 0.97) | 1.02 | (0.87, 1.19) |
| Driver gender | |||||
| Female | 975 (54%) | REF. | REF. | ||
| Male | 843 (46%) | 0.73 | (0.66, 0.81) | 0.68 | (0.60, 0.77) |
| Occupant protection | |||||
| None used | 140 (10%) | REF. | |||
| Shoulder & lap belt | 1,309 (89%) | 0.23 | (0.17, 0.30) | ||
| Lap belt only | 9 (0.3%) | 0.42 | (0.18, 0.99) | ||
| Shoulder belt only | 11 (1%) | 0.85 | (0.34, 2.12) | ||
| Other | 2 (0.1%) | 0.19 | (0.04, 0.97) | ||
| Driver contributing circumstances | |||||
| No error | 282 (16%) | REF. | REF. | ||
| FTYROWb | 185 (11%) | 0.84 | (0.69, 1.02) | 0.87 | (0.69, 1.10) |
| Improper action | 152 (9%) | 0.78 | (0.63, 0.97) | 0.88 | (0.69, 1.12) |
| Failure to obey traffic signals | 60 (3%) | 1.39 | (1.02, 1.89) | 1.34 | (0.94, 1.91) |
| Speeding | 308 (18%) | 2.36 | (1.96, 2.84) | 1.22 | (0.96, 1.56) |
| Lost control | 662 (38%) | 3.43 | (2.92, 4.02) | 1.42 | (1.13, 1.79) |
| Other | 105(6%) | 1.60 | (1.24, 2.05) | 0.84 | (0.62, 1.15) |
| Passenger age | |||||
| No passengers | 1,199 (69%) | REF. | REF. | ||
| One teen passenger | 250 (14%) | 7.86 | (6.40, 9.65) | 4.88 | (3.88, 6.14) |
| Multiple teen passengers | 122 (7%) | 18.29 | (12.50, 26.77) | 10.73 | (7.10, 16.22) |
| Day of week | |||||
| At least one adult passenger | 165 (10%) | 8.17 | (6.35, 10.51) | 7.22 | (5.44, 9.59) |
| Weekday | 1,476 (81%) | REF. | REF. | ||
| Weekend | 348 (19%) | 1.20 | (1.05, 1.37) | 0.88 | (0.74, 1.04) |
a
Odds ratio.
b
Failure to yield right-of-way.