The Effect of Earlier or Automatic Collision Notification on Traffic Mortality by Survival Analysis

Figures & data

Fig. 1 Crash time events and time elapsed between crash (C), notification (N), arrival (A), and death (D) (color figure available online).

Table 1 FARS 2005–2009 population sampled in study

Who?	171,401 drivers and passengers		Data flow
Where?	140,216 passenger car and light truck occupants
When?	108,792 died within 6 h after crash
EMS info related to crash	59,049 died within 6 h, known notification and arrival times
Data of interest	17,187 (died instantly, time 0)	41,862 (died between 1 and 360 min)

Fig. 2 Time between crash and death within 6 h after a crash with inj_SEV = 4 (17,187 instantaneous deaths at time = 0 and 59,049 total deaths at time = 360 min) (color figure available online).

Table 2 Overall, rural, and urban EMS response times since crash (EMS call, arrival, and time to death, in minutes)

Time	Mean (min)	SD (min)	Min (min)	Max (min)
Overall: 41,862 fatalities within 6 h
Call	6.15	16.92	0	348
Arrival	16.54	19.98	0	352
Death	64.72	67.11	1	360
Rural: 26,960 fatalities within 6 h
Call	7.15	18.25	0	337
Arrival	19.30	21.40	0	350
Death	64.69	65.36	1	360
Urban: 14,736 fatalities within 6 h
Call	4.32	14.03	0	348
Arrival	11.52	15.98	0	352
Death	64.52	70.06	1	360

Table 3 Typical cohort study of notification versus traffic severity within 6 h after crash (inj_SEV = 3, 4)

Call time	Inj_SEV = 4	Inj_SEV = 3	Total
Earlier	A	B	A+B
Later	C	D	C+D
Total	41,862	44,003	85,865

Fig. 3 FARS calendar time to research time and randomization (color figure available online).

Fig. 4 Notifications versus occupant survival rates 6 h (inj_SEV = 3, 4, P < .0001) (color figure available online).

Table 4 Survivors and fatalities within 6 h after crash (inj_SEV = 3, 4, P < .0001)

Call time	Dead	Alive	Total	Alive/Total (%)
≤1 min	16,046	17,484	33,530	52.14
>1 min	25,816	26,519	52,335	50.67
Total	41,862	44,003	85,865	51.25

Table 5 Correlation between notification and arrival (correlation coefficient = 0.37)

	Arrival ≤15 min
	and before death	Arrival >15 min	Total
Call ≤1 min	28,156	5374	33,530
Call >1 min	24,892	27,443	52,335
Total	53,048	32,817	85,865

Fig. 5 EMS arrivals versus occupant survival rates within 6 h (inj_SEV = 3, 4, P < .0001) (color figure available online).

Table 6 Survivors and fatalities within 6 h after a crash (inj_SEV = 3, 4, P < .0001)

Arrival time	Dead	Alive	Total	Alive/Total (%)
≤15 min	24,506	28,542	53,048	53.80
>15 min	17,356	15,461	32,817	47.11
Total	41,862	44,003	85,865	51.25

Fig. 6 Occupant survival rates for rural versus urban EMS (inj_SEV = 3, 4, P = .19) (color figure available online).

Table 7 Rural versus urban survival rate comparison (inj_SEV = 3, 4, P = .19)

Location	Dead	Alive	Total	Alive/Total (%)
Rural	26,960	28,063	55,023	51.00
Urban	14,736	15,689	30,425	51.57
Total	41,696	43,752	85,448	51.20

Table 8 Survivors and fatalities within 6 h after a crash (inj_SEV = 3, 4, P < .0001), rural areas only

Arrival time	Dead	Alive	Total	Alive/Total (%)
≤15 min	13,100	15,427	28,527	54.08
>15 min	13,860	12,636	26,496	47.69
Total	26,960	28,063	55,023	51.00

Fig. 7 Occupant fatality rate, Weibull plot with 3 parameters: α (scale) = 826, β (slope) = 0.474, and t ₀ (time shift) = 1.0 for Eq. (2), inj_SEV = 3,4 (earlier EMS notification ≤1 min, FARS 2005–2009) (color figure available online).