Influence of Multiple Freeway Design Features on Freight Traffic Safety

Table 2

MARS model for large truck-involved crashes.

Basis function	Basis function information	Coefficient	Standard error	-value
—	Constant	2.6041	0.0613	<0.0001
Basis1	MAX(Ln(AADT)—11.608235645,0)	1.4315	0.2805	<0.0001
Basis2	MAX(11.608235645—Ln(AADT),0)	−1.7528	0.0691	<0.0001
Basis4	Basis2 ∗ MAX(Number of lanes—3,0)	69.7533	17.9027	<0.0001
Basis6	MAX(Number of lanes—3,0)	−2.6296	0.6865	0.0001
Basis7	MAX(3—Number of lanes,0)	0.2331	0.0739	0.0016
Basis8	Basis6 ∗ ;MAX(Ln(AADT)—11.571194373,0)	−172.570	47.0739	0.0002
Basis9	Basis6 ∗ MAX(11.571194373—ln_adt,0)	−69.6772	17.9034	<0.0001
Basis10	Basis6 ∗ MAX(Ln(AADT)—11.55694235,0)	172.7181	47.0717	0.0002
Basis11	Inside rumble strips	−0.1590	0.0501	0.0479
Basis12	Curve	0.4391	0.0789	<0.0001
Basis13	Basis12 ∗ inside rumble strips	−0.0591	0.0114	0.0013
Basis14	Outside rumble strips	−0.1050	0.0282	0.0031
Basis16	Basis1 ∗ MAX(Inside shoulder width—12,0)	0.8159	0.1552	<0.0001
Basis17	Basis1 ∗ MAX( 12—Inside shoulder width,0)	0.1250	0.0554	0.0241
Basis18	Basis12 ∗ MAX(Inside shoulder width—10,0)	−0.1662	0.0265	<0.0001
Basis19	Basis12 ∗ MAX(10—Inside shoulder width,0)	−0.0258	0.0141	0.0664
Basis20	MAX(Outside shoulder width—10,0)	−0.0417	0.0021	<0.0001
Basis21	MAX(10—Outside shoulder width,0)	0.0807	0.0077	<0.0001
Basis22	Basis12 ∗ MAX(14—Lane width,0)	0.1011	0.0312	0.0028
Basis24	Basis21 ∗ MAX(12—Inside shoulder width,0)	0.0140	0.0061	0.0231
Basis26	Basis14 ∗ MAX(Outside shoulder width—8,0)	0.0183	0.0065	0.0494
AIC = 10332.36