Surveys like this are important to build the case for legislation. Politicians like to do good, and they like it even more if doing good doesn't lose them votes. So it is up to us to create and demonstrate popular support. That's pretty much how it happened for seat belt legislation in the 1970s.
These surveys show that even smokers think smoking should be banned in cars when children are in them.
Also note that some jurisdictions have already enacted this legislation, and when you do so support increases.