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10.6 Drunk Driving Laws and Traffic Deaths 415

TABLE 10.1 Regression Analysis of the Effect of Drunk Driving Laws on Traffic Deaths

Dependent variable: Traffic fatality rate (deaths per 10,000).

Regressor (1) (2) (3) (4) (5) (6) (7)
Beer tax 0.36** - 0.66* - 0.64+
(0.05) (0.29) (0.36) - 0.45 - 0.69* - 0.46 - 0.93**
Drinking age 18 (0.30) (0.35) (0.31) (0.34)

Drinking age 19 0.028 - 0.010 0.037
(0.070) (0.083) (0.102)
Drinking age 20
- 0.018 - 0.076 - 0.065
Drinking age (0.050) (0.068) (0.099)
0.032 - 0.100+
Mandatory jail (0.051) (0.056) - 0.113
or community service? (0.125)
Average vehicle
miles per driver - 0.002
Unemployment rate (0.021)

Real income per capita 0.038 0.085 0.039 0.089
(logarithm) (0.103) (0.112) (0.103) (0.164)
Years
State effects? 0.008 0.017 0.009 0.124
Time effects? (0.007) (0.011) (0.007) (0.049)
Clustered standard errors?
- 0.063** - 0.063** - 0.091**
(0.013) (0.013) (0.021)
1982–88 1982–88 1982–88
no yes yes 1.82** 1.79** 1.00
no no yes (0.64) (0.64) (0.68)
no yes yes
1982–88 1982–88 1982–88 1982 & 1988 only

yes yes yes yes

yes yes yes yes

yes yes yes yes

F-Statistics and p-Values Testing Exclusion of Groups of Variables

Time effects = 0 4.22 10.12 3.48 10.28 37.49
(0.002) ( 6 0.001) (0.006) ( 6 0.001) ( 6 0.001)

Drinking age coefficients = 0 0.35 1.41 0.42
(0.786) (0.253) (0.738)

Unemployment rate, 29.62 31.96 25.20
income per capita = 0 ( 6 0.001) ( 6 0.001) ( 6 0.001)

R2 0.091 0.889 0.891 0.926 0.893 0.926 0.899

These regressions were estimated using panel data for 48 U.S. states. Regressions (1) through (6) use data for all years 1982 to
1988, and regression (7) uses data from 1982 and 1988 only. The data set is described in Appendix 10.1. Standard errors are given
in parentheses under the coefficients, and p-values are given in parentheses under the F-statistics. The individual coefficient is
statistically significant at the +10%, *5%, or **1% significance level.