Table 3 Model estimation results for injury severity analysis of 3-WMR collisions with motorcycles.
From: Factors influencing injury severity in three-wheeled motorized rickshaw and motorcycle collisions
Variables | Severity function: | Parameter estimate | t-Statistic | Major injury | Minor injury | No injury |
|---|---|---|---|---|---|---|
Random variable | ||||||
Off-peak (1 if crash occurred during off peak hours; 0 otherwise) | No injury | − 1.513 | − 1.34 | − 0.0136 | − 0.0294 | 0.0430 |
Standard deviation of “off-peak” random parameter (normally distributed) | 3.263 | 2.32 | ||||
Heterogeneity in the mean of the random parameter | ||||||
Off-peak: daytime | − 1.331 | − 1.88 | ||||
Off-peak: Cloudy weather condition | 1.804 | 2.01 | ||||
Heterogeneity in variance of the random parameter | ||||||
Off-peak: Winter | 0.488 | 3.14 | ||||
Constant | No injury | − 1.197 | − 2.28 | |||
Roadway features | ||||||
Two-lane road (1 if crash occurred on a two-lane road; 0 otherwise) | Major injury | − 0.554 | − 4.07 | − 0.0322 | 0.0268 | 0.0054 |
70 km/hr or more (1 if crash occurred on highway with speed limit equal or more than 70 km/h; 0 otherwise) | Major injury | − 1.239 | − 4.44 | − 0.0149 | 0.0130 | 0.0019 |
Driver characteristics | ||||||
Teen driver (1 if rickshaw driver is less than 20 years; 0 otherwise) | Major injury | − 0.389 | − 2.21 | − 0.0119 | 0.0100 | 0.0019 |
Age 30–40 years (1 if driver age is 30–40 years; 0 otherwise) | Minor injury | 0.413 | 2.42 | − 0.0110 | 0.0147 | − 0.0037 |
Age 40–50 years (1 if driver age is 40–50 years; 0 otherwise) | Minor injury | 0.438 | 2.16 | − 0.0082 | 0.0108 | − 0.0025 |
Female (1 if driver is a female; 0 otherwise) | Minor injury | − 1.861 | − 9.19 | 0.0301 | − 0.0370 | 0.0070 |
Temporal factors | ||||||
Weekend (1 if crash occurred during a weekend; 0 otherwise) | Major injury | − 0.618 | − 4.03 | − 0.0248 | 0.0208 | 0.0040 |
Autumn (1 if crash occurred during Autumn; 0 otherwise) | Major injury | − 0.688 | − 2.62 | − 0.0097 | 0.0081 | 0.0016 |
AM hours (1 if a crash occurred in the AM hours; 0 otherwise) | Minor injury | 0.248 | 1.88 | − 0.0123 | 0.0166 | − 0.0043 |
Environmental factors | ||||||
Rain (1 if a crash occurs under rainy conditions; 0 otherwise) | Major injury | − 0.368 | − 2.07 | − 0.0117 | 0.0107 | 0.0009 |
Sunny (1 if crash occurred under sunny weather condition; 0 otherwise) | No injury | 1.656 | 4.02 | − 0.0407 | − 0.0648 | 0.1055 |
Crash contributing factors | ||||||
Wrong turn (1 if crash contributing factor, is wrongful turn; 0 otherwise) | Minor injury | − 2.392 | − 2.11 | 0.0011 | − 0.0016 | 0.0005 |
Speed (1 if crash contributing factor is over speeding; 0 otherwise) | No injury | − 1.648 | − 3.74 | 0.0371 | 0.0642 | − 0.1013 |
Distracted (1 if crash contributing factor is distracted driving; 0 otherwise) | No injury | − 0.925 | − 1.79 | 0.0040 | 0.0059 | − 0.0099 |
Model fit statistics | ||||||
Number of observations | 1241 | |||||
Log likelihood at zero | − 1363.38 | |||||
Log likelihood at convergence | − 1131.66 | |||||
McFadden R-Sq | 0.17 | |||||
