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.