In November 1986, the Massachusetts mandatory seat belt use law repealed in a referendum by a 53 per cent to 47 per cent vote. In an anonymous random digit telephone survey of 1,046 adults in Massachusetts in summer 1986, while the law was in effect, 61 per cent of respondents had said they would vote in favor of the law. A post-repeal follow-up of 80 per cent of these persons revealed initial supporters and opponents of the law were equally likely to vote, but 15 per cent of the summer supporters switched their opinions and voted for repeal, compared to only 4 per cent of summer opponents who switched. In addition, a separate survey of 167 households that had refused to answer the summer survey indicated that survey nonrespondents were more likely to vote against the law than for it. Those opposing the law saw it as an infringement on personal liberty and believed it was not effective in reducing injury and death.