Table 2.

Results of ARIMA Models for Counts of Alcohol-Involved Crashes, Los Angeles

DUI interventions	Sobriety checkpoints		Saturation patrols
	b (95% CI)	p-value	b (95% CI)	p-value
Dailya,b
On day t	–0.01 (–0.06, 0.03)	0.617	0.02 (–0.04, 0.08)	0.539
In previous 1 day	–0.02 (–0.07, 0.02)	0.312	0.03 (–0.03, 0.08)	0.389
In previous 2 days	–0.01 (–0.04, 0.02)	0.425	0.00 (–0.03, 0.04)	0.875
In previous 3 days	–0.01 (–0.04, 0.01)	0.190	–0.02 (–0.05, 0.01)	0.305
In previous 4 days	–0.02 (–0.04, 0.00)	0.036	–0.02 (–0.04, 0.00)	0.120
In previous 5 days	–0.02 (–0.03, 0.00)	0.031	–0.01 (–0.03, 0.01)	0.286
In previous 6 days	–0.02 (–0.03, 0.00)	0.011	–0.01 (–0.03, 0.01)	0.449
In previous 7 days	–0.02 (–0.03, 0.00)	0.028	–0.01 (–0.03, 0.01)	0.413
Weeklyc
On week t	–0.07 (–0.60, 0.46)	0.793	–0.29 (–0.87, 0.28)	0.314
In previous 1 week	–0.56 (–1.06, –0.06)	0.029	0.02 (–0.61, 0.65)	0.956
In previous 2 weeks	–0.31 (–0.66, 0.04)	0.085	–0.28 (–0.70, 0.15)	0.202
In previous 3 weeks	–0.08 (–0.38, 0.21)	0.593	–0.11 (–0.48, 0.27)	0.568
In previous 4 weeks	–0.02 (–0.28, 0.25)	0.901	–0.01 (–0.33, 0.32)	0.970
Monthlya,d
On month t	–0.01 (–0.06, 0.04)	0.679	0.02 (–0.03, 0.08)	0.420
In previous 1 month	0.01 (–0.03, 0.04)	0.635	0.02 (–0.05, 0.08)	0.615
In previous 2 months	0.02 (0.00, 0.05)	0.100	0.03 (–0.02, 0.08)	0.273
In previous 3 months	0.00 (–0.03, 0.03)	0.988	0.01 (–0.03, 0.05)	0.548

Notes: Boldface indicates statistical significance (p<0.05).

^aOutcome variable square root transformed for the daily and monthly time-series.

^bDaily time series null model: ARIMA(0,1,1)(0,1,1)₇: Q(40 lags)=33.9.

^cWeekly time series null model: ARIMA(0,1,1)(1,1,0)₅₂: Q(40 lags)=43.2.

^dMonthly time series null model: ARIMA(0,1,1)(0,1,1)₁₂: Q(40 lags)=12.3.

ARIMA, autoregressive integrated moving average; DUI, driving under the influence (of alcohol).