Table 1

 Prevalence of smoking in cars by site, time, and weather conditions

Key characteristicsTotal cars observedAny smoking in the carRate ratio for smoking in cars versus no smoking (95% CI)Driver smoking in cars with smokingOther occupant present in cars with smokingWindow open in cars with smoking
*Calculated as a proportion of the number of cars with any smoking occurring (by driver or a passenger).
†The corners of: Kent Terrace/Vivian St; Jervois Quay/Cable St; and Taranaki St/Vivian St (n = 2000 cars each).
High deprivation area site (Wainuiomata)50553256.43.18 (2.55 to 3.97)31697.26921.226481.2
Central business district (3 sites†)60002333.91.92 (1.53 to 2.42)21692.76226.619583.7
Low deprivation area site (Karori)50001012.01.0 (reference)9695.12524.88180.2
Total (95% CI for per cents)160556594.1 (3.8 to 4.4)62895.3 (93.4 to 95.8)15623.7 (20.5 to 27.1)54081.9 (78.8 to 84.8)
Time of day
Morning (8–10 am)80553724.61.29 (1.11 to 1.50)35495.28121.831484.4
Afternoon (4–6 pm)80002873.61.0 (reference)27495.57526.122678.8
Overcast/rain89394004.51.23 (1.05 to 1.43)37994.88521.333583.8
Sunny71162593.61.0 (reference)24996.17127.420579.2