Research Article
Analysis of Rear-End Crash on Thai Highway: Decision Tree Approach
Table 4
Correlation among independent variables.
| | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 |
| (1) Vehicle types | 1.00 | −0.05 | 0.11 | −0.20 | 0.07 | 0.02 | −0.01 | 0.14 | 0.16 | −0.03 | −0.05 | 0.05 | −0.03 | 0.02 | 0.07 | 0.08 | 0.06 | −0.02 | −0.02 | 0.09 | 0.15 | 0.03 | (2) CrashType | | 1.00 | 0.01 | 0.02 | −0.09 | 0.00 | 0.01 | −0.10 | −0.10 | 0.00 | 0.04 | −0.07 | 0.16 | 0.16 | −0.10 | −0.08 | −0.02 | −0.05 | 0.00 | −0.16 | −0.10 | −0.23 | (3) Person_age | | | 1.00 | −0.13 | −0.01 | −0.02 | −0.01 | 0.02 | 0.03 | −0.01 | 0.02 | 0.00 | 0.01 | 0.02 | 0.00 | 0.01 | −0.01 | 0.00 | 0.02 | 0.01 | 0.00 | −0.04 | (4) Gender | | | | 1.00 | −0.02 | −0.01 | −0.01 | −0.05 | −0.04 | 0.00 | 0.02 | −0.02 | 0.03 | −0.03 | −0.02 | −0.02 | −0.08 | 0.04 | −0.01 | −0.04 | −0.04 | 0.00 | (5) Main_Road | | | | | 1.00 | −0.02 | −0.01 | 0.40 | 0.23 | −0.17 | 0.06 | −0.04 | −0.05 | −0.04 | 0.01 | 0.01 | 0.08 | 0.04 | −0.01 | 0.35 | 0.07 | 0.06 | (6) Entran_Exit | | | | | | 1.00 | 0.01 | 0.13 | 0.05 | −0.01 | 0.02 | −0.01 | 0.02 | −0.03 | −0.02 | −0.02 | 0.00 | 0.00 | −0.01 | 0.13 | 0.02 | 0.03 | (7) Normal | | | | | | | 1.00 | 0.06 | 0.05 | −0.03 | 0.02 | 0.00 | 0.00 | 0.00 | 0.03 | 0.03 | 0.00 | −0.02 | 0.02 | 0.05 | 0.01 | −0.03 | (8) Road_lane | | | | | | | | 1.00 | 0.62 | −0.22 | 0.11 | −0.09 | −0.12 | 0.05 | −0.01 | −0.01 | 0.12 | 0.06 | −0.05 | 0.60 | 0.17 | 0.09 | (9) Road_isle | | | | | | | | | 1.00 | −0.13 | 0.12 | −0.08 | −0.12 | 0.16 | 0.02 | 0.03 | 0.09 | 0.09 | −0.04 | 0.48 | 0.26 | 0.06 | (10) Asphalt | | | | | | | | | | 1.00 | −0.05 | 0.04 | −0.06 | −0.08 | 0.06 | 0.03 | −0.10 | 0.07 | 0.03 | −0.10 | −0.04 | −0.06 | (11) Straight | | | | | | | | | | | 1.00 | −0.39 | 0.03 | 0.03 | −0.11 | −0.08 | 0.03 | 0.05 | 0.01 | 0.07 | −0.07 | 0.01 | (12) Slope | | | | | | | | | | | | 1.00 | −0.05 | −0.04 | 0.05 | 0.04 | −0.02 | −0.07 | 0.00 | −0.06 | 0.09 | −0.04 | (13) Intersection | | | | | | | | | | | | | 1.00 | 0.08 | −0.07 | −0.06 | 0.00 | −0.06 | 0.03 | −0.11 | −0.05 | −0.09 | (14) Median_open | | | | | | | | | | | | | | 1.00 | −0.02 | −0.03 | −0.01 | −0.01 | 0.00 | −0.05 | 0.03 | −0.11 | (15) Env_surfaces | | | | | | | | | | | | | | | 1.00 | 0.84 | −0.02 | 0.00 | −0.01 | −0.03 | 0.04 | 0.07 | (16) Weather | | | | | | | | | | | | | | | | 1.00 | 0.02 | 0.00 | 0.01 | −0.03 | 0.04 | 0.06 | (17) Env_light | | | | | | | | | | | | | | | | | 1.00 | −0.05 | 0.02 | 0.10 | 0.06 | 0.04 | (18) SafetyEqui | | | | | | | | | | | | | | | | | | 1.00 | −0.01 | 0.08 | −0.01 | 0.00 | (19) Alcohol | | | | | | | | | | | | | | | | | | | 1.00 | −0.04 | −0.04 | −0.08 | (20) AADT60 | | | | | | | | | | | | | | | | | | | | 1.00 | 0.03 | 0.12 | (21) PerCTruck | | | | | | | | | | | | | | | | | | | | | 1.00 | 0.03 | (22) SpeedExc | | | | | | | | | | | | | | | | | | | | | | 1.00 |
|
|
Note: Bold number represented correlation, which is significant at the 0.05 level (2-tailed).
|