Predictor variables and initial and final results from the regression
| Variable (frequency) | Initial model | Final model | ||
|---|---|---|---|---|
| Coefficient | SE | Coefficient | SE | |
| Intercept | 11.05 | 6.19 | 7.67 | 4.29 |
| Dark 0=No (101); 1=yes (56) | −0.81 | 2.56 | ||
| Weather 0=No (121); 1=yes (37) | −2.69 | 2.85 | ||
| Soft surface 0=No (148); 1=yes (10) | 4.17 | 6.04 | ||
| Slope 0=No (122); 1=yes (36) | −0.04 | 3.14 | ||
| Physical obstruction 0=No (128); 1=yes (30) | 8.30 | 3.45 | 10.31 | 2.44 |
| Number of vehicles 1=1 (33); 2=2 (102); 3=3+ (22) | −0.24 | 2.17 | ||
| Vehicle type 0=hatchback (122); 1=other (35) | 1.38 | 1.40 | ||
| Number of doors 0=1–4 (52); 1=5+ (104) | 0.25 | 1.21 | ||
| Vehicle age (years) mean 6.9 SD 4.2 | −0.19 | 0.27 | ||
| Multiple 0=No (117); 1=Yes (38) | 1.79 | 3.03 | ||
| Intrusion passenger compartment 0=no (110); 1=yes (45) | 1.30 | 3.04 | ||
| Vehicle on side 0=no (146); 1=yes (9) | −1.68 | 2.85 | ||
| Vehicle on roof 0=no (151); 1=yes (4) | −10.97 | 3.63 | −11.61 | 3.17 |
| Halts 0=no (126); 1=yes (32) | 2.36 | 1.63 | ||
| Number patients medically trapped 0=0 (10); 1=1 (120); 2=2 (25) | 8.96 | 2.72 | 10.29 | 2.17 |
| Number patients physically trapped 0=0 (140); 1=1+ (16) | 5.06 | 2.53 | 6.71 | 1.77 |
| Access 0=controlled (142); 1=rapid (7) | −7.41 | 2.56 | −7.30 | 2.30 |