Table 2.

Results of the Generalized Estimating Equation (GEE) models for time headway at lead vehicle (LV) brake onset in different driving conditions.

Speech-Based Texting					Handheld Texting
Parameter	Estimate	SE	z	p > |z|	Estimate	SE	z	p > |z|
Intercept	1.97	0.16	12.67	<0.001	2.17	0.16	13.91	<0.001
Gender (Female *)	0.07	0.19	0.38	0.702	−0.05	0.19	−0.24	0.808
Speech-based texting (No phone *)	0.41	0.10	4.20	<0.001
Difficulty in speech-based texting (Simple *)	0.15	0.11	1.37	0.169
Handheld texting (No phone *)					0.59	0.09	6.37	<0.001
Difficulty in handheld texting (Simple *)					0.01	0.11	0.14	0.890
The goodness of fit for models	Wald chi2(3) = 19.64, Prob > chi2 = 0.0002				Wald chi2(3) = 40.71, Prob > chi2 = 0.0000

SE = Standard Error; * Reference category.