Table 4.
Results of multivariate analysis between cell phone legislation and fatal collision by sub-groupa
| Characteristic | Sub-group | Model 1 IRRb (95% CI) |
Model 2 IRRb (95% CI) |
|---|---|---|---|
| Overall | |||
| Hand-held ban | 0.88 (0.81, 0.96) | 0.90 (0.84, 0.97) | |
| Texting ban | 1.03 (0.96, 1.10) | 1.03 (0.91, 1.16) | |
| Age | |||
| 16–24 year olds | |||
| Hand-held ban | 0.84 (0.72, 0.97) | 0.86 (0.76, 0.97) | |
| Texting ban | 0.99 (0.90, 1.09) | 1.00 (0.71, 1.40) | |
| 25–39 year olds | |||
| Hand-held ban | 0.84 (0.79, 0.90) | 0.86 (0.80, 0.93) | |
| Texting ban | 1.05 (0.93, 1.18) | 1.05 (0.77, 1.44) | |
| 40–59 year olds | |||
| Hand-held ban | 0.86 (0.80, 0.93) | 0.89 (0.84, 0.95) | |
| Texting ban | 1.01 (0.93, 1.10) | 1.01 (0.74, 1.38) | |
| >60 year olds | |||
| Hand-held ban | 0.91 (0.84, 1.00) | 0.92 (0.86, 0.99) | |
| Texting ban | 1.02 (0.97, 1.08) | 1.02 (0.97, 1.07) | |
| Sex | |||
| Males | |||
| Hand-held ban | 0.89 (0.83, 0.96) | 0.91 (0.85, 0.97) | |
| Texting ban | 1.03 (0.95, 1.12) | 1.03 (0.86, 1.24) | |
| Females | |||
| Hand-held ban | 0.86 (0.78, 0.96) | 0.88 (0.81, 0.97) | |
| Texting ban | 1.02 (0.95, 1.08) | 1.02 (0.83, 1.25) | |
| Race/ethnicity | |||
| White non-Hispanic | |||
| Hand held ban | 0.90 (0.76, 1.05) | 0.93 (0.79, 1.09) | |
| Texting ban | 1.12 (0.97, 1.30) | 1.11 (0.96, 1.28) | |
| White Hispanic | |||
| Hand held ban | 0.87 (0.72, 1.06) | 0.83 (0.67, 1.04) | |
| Texting ban | 0.88 (0.63, 1.24) | 0.90 (0.52, 1.55) | |
| Black non-Hispanic | |||
| Hand held ban | 0.86 (0.72, 1.02) | 0.89 (0.75, 1.05) | |
| Texting ban | 0.97 (0.80, 1.16) | 0.94 (0.74, 1.18) | |
| Other | |||
| Hand held ban | 0.88 (0.47, 1.68) | 0.93 (0.75, 1.15) | |
| Texting ban | 0.85 (0.02, 36.85) | 0.85 (0.06, 12.35) | |
| Location | |||
| Urban | |||
| Hand held ban | 0.85 (0.67, 1.07) | 0.88 (0.77, 1.00) | |
| Texting ban | 1.01 (0.88, 1.15) | 0.99 (0.92, 1.07) | |
| Rural | |||
| Hand held ban | 0.89 (0.82, 0.95) | 0.90 (0.45, 1.83) | |
| Texting ban | 1.03 (0.96, 1.11) | 1.04 (0.96, 1.13) |
Abbreviations: CI=confidence interval; IRR=incident rate ratio
Model 1 contained variables for presence of universal texting ban (binary), presence of universal hand-held ban (binary), quarter (continuous), spline knots and year (continuous). Model 2 included variables for presence of universal texting ban (binary), presence of universal hand-held ban (binary), quarter (continuous), spline knots, year (continuous), log of adjusted per capita income, log of unemployment rate, log of adjusted gas price, maximum state speed limits ≥70 miles per hour (binary), presence of administrative license suspension (binary), presence of per se minimum blood alcohol concentration ≥ 0.08 g/dl (binary), presence of primary seat belt laws for front seat passengers (binary), log of cell phone coverage, presence of graduated drivers licensing laws (binary), and log of police population. Model 1 and Model 2 were stratified analyses. Because the focus of this analysis was the relationship between legislation and fatal collision rate, only the IRR pertaining to the bans were shown for ease of presentation.