Table 3.
Variable descriptions and data summary.
| Variables | Mean | S.D. | Min. | Max. | Percent of ‘1’ | Description |
|---|---|---|---|---|---|---|
| Human Factors | ||||||
| Demographic profiles | ||||||
| Driver | – | – | – | – | 57.54% | Driver 1; else 0 |
| Driver age | 39.95 | 14.72 | 16.00 | 80.00 | – | Driver’s age, from 16 to 80 |
| Driver sex | – | – | – | – | 59.82% | Male 1; else 0 |
| Occupant age | 36.55 | 17.49 | 1.00 | 99.00 | – | The occupant’s age, from 16 to 104 |
| Occupant sex | – | – | – | – | 56.69% | Male 1; else 0 |
| Number of injured occupants | 1.91 | 2.03 | 0.00 | 34.00 | – | The number of occupants |
| Behavioral factors | ||||||
| Alcohol use | – | – | – | – | 7.26% | If the driver used alcohol 1; else 0 |
| Driver safety equipment use | – | – | – | – | 57.83% | If the driver used safety equipment 1; else 0 |
| Improper driving | – | – | – | – | 36.51% | If the driver didn’t drive properly 1; else 0 |
| Unsafe speed | – | – | – | – | 39.05% | If the speed was too fast or too slow 1; else 0 |
| Occupant safety equipment use | – | – | – | – | 56.75% | If the occupant used safety equipment 1; else 0 |
| Natural and Road Environment Factors | ||||||
| Temporal factors | ||||||
| Summer | – | – | – | – | 11.25% | June, July, and August, 1; else 0 |
| Weekday | – | – | – | – | 83.59% | If the collision occurred during weekdays 1; else 0 |
| Nighttime | – | – | – | – | 25.92% | If the collision occurred during nighttime (06:00 p.m.-06:00 a.m.) 1; else 0 |
| Environmental factors | ||||||
| Bad weather | – | – | – | – | 3.11% | Bad weather days, including rain, snow, fog weathers, 1; else 0 |
| Dark/No streetlight | – | – | – | – | 5.46% | No streetlight or non-functioning lights 1; else 0 |
| Slippery road surfaces | – | – | – | – | 6.06% | If road surface condition is wet or slippery 1; else 0 |
| Location characteristics | ||||||
| Intersection | – | – | – | – | 15.72% | If the collision occurred at an intersection 1; else 0 |
| Ramp | – | – | – | – | 4.67% | If the collision occurred on a ramp 1; else 0 |
| Collision characteristics | ||||||
| Head-on | – | – | – | – | 3.54% | If the collision is head-on 1; else 0 |
| Side-swipe | – | – | – | – | 26.84% | If the collision is side-swipe 1; else 0 |
| Rear-end | – | – | – | – | 44.48% | If the collision is rear-end 1; else 0 |
| Vehicle Characteristics | ||||||
| Years of vehicle usage | 9.12 | 6.79 | 0.00 | 58.00 | – | The difference between the model year and the year of collision |
| Vehicle size | 2.47 | 0.83 | 1.00 | 4.00 | – | Motorcycle or scooter 1, passenger car 2, light truck or emergency car 3, large truck or large vehicle (bus) 4 |