Table 1. Carbon dioxide emissions and fuel economy
OLS IV
(1) (2) (3) (4) (5) (6) (7) (8)
Log fuel economy 0.982 0.985 0.989 0.987 0.993 0.994 0.995 0.998
(0.003) (0.002) (0.002) (0.002) (0.002) (0.002) (0.002) (0.002)
Year −0.004 −0.004
(0.001) (0.001)
Year2 0.0004 0.0004
(0.0001) (0.0001)
Diesel