Table 3

Drivers who conversed on a hand-held cellphone while driving

Characteristic	Per cent engaged in behaviour*	Legislation	Model 1† RR (95% CI)	Model 2† RR (95% CI)	Model 3† RR (95% CI)	Interaction p value‡
Overall	53.2	Hand-held ban	0.61 (0.56 to 0.66)	0.60 (0.55 to 0.66)	0.60 (0.54 to 0.67)
		Texting ban		1.03 (0.96 to 1.11)	0.99 (0.92 to 1.06)
Age group						0.0414
19–24	66.1	Hand-held ban	0.72 (0.56 to 0.91)	0.71 (0.56 to 0.89)	0.77 (0.62 to 0.94)
		Texting ban		1.02 (0.92 to 1.14)	1.00 (0.89 to 1.12)
25–39	64.9	Hand-held ban	0.64 (0.55 to 0.73)	0.63 (0.55 to 0.73)	0.64 (0.55 to 0.73)
		Texting ban		1.01 (0.93 to 1.10)	0.97 (0.89 to 1.05)
40–59	55.7	Hand-held ban	0.62 (0.56 to 0.68)	0.61 (0.55 to 0.67)	0.60 (0.54 to 0.67)
		Texting ban		1.06 (0.99 to 1.14)	1.03 (0.95 to 1.12)
≥60	38.8	Hand-held ban	0.47 (0.39 to 0.57)	0.48 (0.40 to 0.59)	0.47 (0.37 to 0.59)
		Texting ban		0.91 (0.73 to 1.12)	0.94 (0.75 to 1.18)
Sex						0.1387
Men	53.1	Hand-held ban	0.65 (0.56 to 0.74)	0.64 (0.55 to 0.74)	0.64 (0.54 to 0.75)
		Texting ban		1.04 (0.95 to 1.14)	1.01 (0.91 to 1.11)
Women	53.5	Hand-held ban	0.57 (0.52 to 0.63)	0.57 (0.52 to 0.62)	0.57 (0.51 to 0.62)
		Texting ban		1.02 (0.92 to 1.13)	0.97 (0.88 to 1.07)
Race/Ethnicity						0.5244
White non-Hispanic	54.5	Hand-held ban	0.59 (0.51 to 0.69)	0.59 (0.51 to 0.68)	0.59 (0.51 to 0.68)
		Texting ban		1.04 (0.93 to 1.17)	1.00 (0.92 to 1.10)
Black non-Hispanic	50.3	Hand-held ban	0.61 (0.45 to 0.83)	0.64 (0.47 to 0.87)	0.63 (0.46 to 0.88)
		Texting ban		0.86 (0.68 to 1.10)	0.84 (0.65 to 1.09)
Hispanic	48.1	Hand-held ban	0.64 (0.55 to 0.73)	0.61 (0.51 to 0.73)	0.63 (0.54 to 0.74)
		Texting ban		1.09 (0.94 to 1.25)	1.01 (0.89 to 1.16)
Others	49.0	Hand-held ban	0.62 (0.50 to 0.77)	0.62 (0.49 to 0.79)	0.64 (0.53 to 0.77)
		Texting ban		1.01 (0.78 to 1.30)	0.95 (0.73 to 1.23)
Location						0.8190
Urban	53.0	Hand-held ban	0.61 (0.56 to 0.66)	0.60 (0.55 to 0.65)	0.60 (0.54 to 0.66)
		Texting ban		1.05 (0.98 to 1.13)	1.01 (0.95 to 1.07)
Rural	54.8	Hand-held ban	0.62 (0.49 to 0.79)	0.64 (0.50 to 0.82)	0.66 (0.51 to 0.86)
		Texting ban		0.92 (0.76 to 1.12)	0.91 (0.74 to 1.13)

*This is the percentage of respondents who reported to engage in the behaviour out of total number who responded to the questions pertaining to hand-held cellphone conversations in the demographic group.
†The outcome was whether or not the driver self-reported to converse on a hand-held cellphone in the 30 days prior to survey. The exposure was the cellphone legislation. The RR presented compares drivers exposed to the ban to those who were not exposed; while the models contained several variables, only the RR pertaining to the universal hand-held ban and universal texting ban were shown for ease of presentation. Model 1 contained universal hand-held ban (binary) only. Model 2 contained variables for the universal hand-held ban (binary), universal texting ban (binary), and year of survey. Model 3 contained all terms from Model two and additionally controlled for sex, age group, race/ethnicity, marital status, education and household income. In Model 3, if the model was for a particular characteristic it was not adjusted for that characteristic (example: if a model was for male sex, it was not adjusted for sex).
‡A fourth model containing variables from Model 2, driver characteristic, and an interaction term between the legislative ban and the driver characteristic were run to formally test for sub-group differences. The p-value presented is for the interaction term between the presence of the universal hand-held ban and the driver characteristic. While the models contained several variables, only the p-value was shown for ease of presentation.