Table 1

Percent of parents and teens reporting use of a driving agreement and odds ratios and 95% confidence intervals for differences

No (%) of parentsNo (%) of teens
TimeIntervention groupControl groupOdds ratio95% Confidence intervalsIntervention groupControl groupOdds ratio95% Confidence intervals
Month 1283 (62)296 (38)3.142.23 to 4.41283 (65)296 (35)4.983.48 to 7.13
Month 4253 (65)276 (35)4.793.31 to 6.94253 (69)276 (31)6.464.42 to 9.44
Month 9249 (61)279 (39)3.042.13 to 4.34249 (69)279 (31)4.783.29 to 6.94