Evaluating Effect of Operating Speed on Crashes of Rural Two-Lane Highways

Table 4

Comparison of models for medium-speed roads.

	Traditional model			Speed-based model
	Coefficient	Std. error	95% CI	Coefficient	Std. error	95% CI
Intercept ()	−4.58	0.057	(−4.69, −4.47)	−4.32	0.067	(−4.46, −4.19)
Ln (AADT)	0.88	0.008	(0.87, 0.90)	0.91	0.009	(0.89, 0.92)
Ln (L)	1.06	0.013	(1.03, 1.08)	1.07	0.013	(1.05, 1.09)
Average speed	_			−0.01	0.001	(−0.01, −0.007)
Model form
MAPE	61.04%			60.89%
RMSE	2.85			2.84
MAD	1.52			1.52

Note: value <0.0001 for all the variables.