Analysis of Rear-End Crash on Thai Highway: Decision Tree Approach

Table 2

Categorical Variables’ characteristics and descriptive statistics.

		Driver exposure				Fatal injury
		Not-at-fault		At-fault		Fatal crash		Nonfatal crash
		Count	%	Count	%	Count	%	Count	%
Veh_type	Small	718	15.8%	833	18.3%	387	8.5%	1164	25.6%
	Middle	1078	23.7%	1274	28.0%	533	11.7%	1819	39.9%
	Large	300	6.6%	351	7.7%	236	5.2%	415	9.1%
Crashtype	Stopped	1344	29.5%	1611	35.4%	721	15.8%	2234	49.1%
	Decelerating	645	14.2%	705	15.5%	347	7.6%	1003	22.0%
	Go Straight	107	2.3%	142	3.1%	88	1.9%	161	3.5%
Gender	Female	1731	38.0%	2037	44.7%	1000	22.0%	2768	60.8%
	Male	365	8.0%	421	9.2%	156	3.4%	630	13.8%
Main_road	Other wise	1895	41.6%	2193	48.2%	1070	23.5%	3018	66.3%
	Yes	201	4.4%	265	5.8%	86	1.9%	380	8.3%
Entran_exit	Other wise	2084	45.8%	2448	53.8%	1154	25.3%	3378	74.2%
	Yes	12	0.3%	10	0.2%	2	0.0%	20	0.4%
Nonrepairing road	Other wise	54	1.2%	59	1.3%	28	0.6%	85	1.9%
	Yes	2042	44.8%	2399	52.7%	1128	24.8%	3313	72.7%
Road_lane	2	710	15.6%	792	17.4%	385	8.5%	1117	24.5%
	3	10	0.2%	11	0.2%	4	0.1%	17	0.4%
	4	926	20.3%	1083	23.8%	573	12.6%	1436	31.5%
	5	9	0.2%	8	0.2%	5	0.1%	12	0.3%
	6	155	3.4%	202	4.4%	63	1.4%	294	6.5%
	7	0	0.0%	2	0.0%	0	0.0%	2	0.0%
	8	160	3.5%	205	4.5%	92	2.0%	273	6.0%
	9	3	0.1%	4	0.1%	5	0.1%	2	0.0%
	10	33	0.7%	59	1.3%	21	0.5%	71	1.6%
	12	60	1.3%	65	1.4%	8	0.2%	117	2.6%
	14	30	0.7%	27	0.6%	0	0.0%	57	1.3%
Road_isle	No median	779	17.1%	861	18.9%	399	8.8%	1241	27.3%
	Flush	115	2.5%	133	2.9%	96	2.1%	152	3.3%
	Raised	452	9.9%	561	12.3%	298	6.5%	715	15.7%
	Depressed	513	11.3%	612	13.4%	264	5.8%	861	18.9%
	Barrier	237	5.2%	291	6.4%	99	2.2%	429	9.4%
Asphalt	Other wise	242	5.3%	309	6.8%	124	2.7%	427	9.4%
	Yes	1854	40.7%	2149	47.2%	1032	22.7%	2971	65.2%
Straight	Other wise	125	2.7%	172	3.8%	96	2.1%	201	4.4%
	Yes	1971	43.3%	2286	50.2%	1060	23.3%	3197	70.2%
Slope	Other wise	2039	44.8%	2358	51.8%	1090	23.9%	3307	72.6%
	Yes	57	1.3%	100	2.2%	66	1.4%	91	2.0%
Intersection	Nonintersection	1725	37.9%	2013	44.2%	985	21.6%	2753	60.5%
	Intersection	371	8.1%	445	9.8%	171	3.8%	645	14.2%
Median_opening	Other wise	1853	40.7%	2129	46.8%	985	21.6%	2997	65.8%
	Yes	243	5.3%	329	7.2%	171	3.8%	401	8.8%
Env_surfaces	Dry	1951	42.8%	2284	50.2%	1073	23.6%	3162	69.4%
	Wet	145	3.2%	174	3.8%	83	1.8%	236	5.2%
Weather	Otherwise	1947	42.8%	2266	49.8%	1063	23.3%	3150	69.2%
	Clean	149	3.3%	192	4.2%	93	2.0%	248	5.4%
Env_light	Day	1413	31.0%	1629	35.8%	669	14.7%	2373	52.1%
	Nigh without light	217	4.8%	243	5.3%	194	4.3%	266	5.8%
	Night with light	466	10.2%	586	12.9%	293	6.4%	759	16.7%
SafetyEqui	Other wise	1312	28.8%	1585	34.8%	856	18.8%	2041	44.8%
	Use	784	17.2%	873	19.2%	300	6.6%	1357	29.8%
Alcohol	Other wise	2070	45.5%	2433	53.4%	1131	24.8%	3372	74.0%
	Yes	26	0.6%	25	0.5%	25	0.5%	26	0.6%
SpeedExc	Other wise	651	14.3%	734	16.1%	387	8.5%	998	21.9%
	Yes	1445	31.7%	1724	37.9%	769	16.9%	2400	52.7%