Exploring Driver Injury Severity in Single-Vehicle Crashes under Foggy Weather and Clear Weather

Table 1

Classification statistics of variables.

Variables	SVCF		SVCC		Total
	Number	Rate (%)	Number	Rate (%)	Number	Rate (%)
Number of crashes	5138	50.7	4999	49.3	10137	100
Severity
No injury	3253	63.3	3601	72.0	6854	67.6
Slight injury	1135	22.0	916	18.3	2051	20.2
SFI	750	14.7	482	9.7	1232	12.2
Driver characteristics
Driver gender
Male	4860	94.5	4622	92.4	9482	93.5
Female	278	5.5	377	7.6	655	6.5
Driver age
<30	1195	23.3	1095	21.9	2290	22.6
30–60	3658	71.2	3588	71.8	7246	71.5
>60	285	5.5	316	6.3	601	5.9
Seat belt used
Not used	1211	23.6	875	17.6	2086	20.6
Used	3927	76.4	4124	82.4	8051	79.4
Alcohol-impaired
No	4552	82.6	4264	85.3	8816	83.9
Yes	586	11.4	735	14.7	1321	13.1
Career
Staff	594	11.5	809	16.1	1403	13.8
Self-employed	768	14.9	1042	20.8	1810	17.8
Farmer	3296	64.1	2622	52.4	5918	58.3
Others	480	9.3	526	10.5	1006	9.9
Driving experience
<4 years	983	19.1%	1031	20.6%	2048	20.2%
4–10 years	2026	39.4%	1871	37.4%	3943	38.9%
>10 years	2125	41.4%	1977	39.5%	4146	40.9%
Driving license
With license	4530	88.1%	4484	89.6%	9014	89.0%
Without license	608	11.9%	515	10.3%	1123	11.0%
Vehicle characteristics
Vehicle type
Passenger car	1859	36.1%	2019	40.3%	3878	38.2%
Motorcycle	1642	31.9%	1101	22.0%	2743	27.0%
Pickup	351	6.8%	439	8.7%	790	7.7%
Truck	1114	21.6%	1194	23.8%	2308	22.7%
Other	172	3.3%	246	4.9%	418	4.1%
Road characteristics
Road surface
Non-dry	526	10.2%	263	5.3%	789	7.8%
Dry	4612	89.7%	4736	94.7%	9348	92.2%
Other characteristics
Traffic controls
No control	1684	32.7%	1516	30.3%	3200	31.5%
Signal control	205	3.9%	292	5.8%	497	4.9%
Stop-yield sign	2899	56.4%	2964	59.2%	5863	57.8%
Other control methods	350	6.8%	227	4.5%	577	5.8%
Week
Monday or Friday	2216	43.1%	1394	27.8%	2867	28.2%
Tuesday–Thursday	1473	28.6%	2213	44.2%	4429	43.6%
Weekend	1449	28.2%	1392	27.8%	2841	28.0%
Intersection
No	3981	77.4%	3563	71.2%	7544	74.4%
Yes	1157	22.6%	1436	28.7%	2593	25.5
Time of accident
00 : 00–07 : 00	1068	20.7%	442	8.8%	1510	14.8%
07 : 00–09 : 00	299	5.8%	1056	21.1%	1355	13.3%
09 : 00–17 : 00	802	15.6%	2613	52.2%	3415	33.6%
17 : 00–20 : 00	1587	30.8%	664	13.2%	2251	22.2%
20 : 00–24 : 00	1382	26.8%	224	4.4%	1606	15.8%
Area
Urban	3011	58.6%	3494	69.8%	6505	64.2%
Rural	2127	41.3%	1505	30.2%	3632	35.8%
Crash type
Non-fixed object	3670	71.4%	4234	84.6%	7904	77.9%
Fixed object	334	6.5%	195	3.9%	529	5.2%
Collision with pedestrian	1079	21.0%	500	10.0%	1579	15.5%
Other object	55	1.1%	70	1.4%	125	1.2%

Note: indicates that that variable was a reference variable in the model.