Table 1 The key questions that need to be addressed in the identified threats to legislation banning smoking in vehicles carrying children

   Is the severity of the problem sufficient to justify a law?

1. PROBLEM MISIDENTIFICATION

a. Is it possible to show that exposure to second-hand smoke in cars leads to ill-health?

b. What toxicity levels are encountered in a car when cigarettes are smoked?

c. Does ventilation make a difference?

d. Are the toxicity levels comparable to other risky environments in which smoking bans already operate?

e. How does the potential harm compare to formally approved air quality standards?

2. LACK OF PUBLIC SUPPORT

   Is there likely to be public support for such a law?

a. What is the overall magnitude of support for such a law?

b. What are the levels of support amongst smokers?

c. What is the motivation behind public support?

d. Does endorsement depend on the extent and success of previous smoking bans in work and public places?

3. LOBBY GROUP OPPOSITION

   Is there likely to be effective pressure group opposition?

a. Has the Tobacco lobby opposed this particular ban?

b. Are they likely to do so in future?

4. ENFORCEMENT

   Is the law enforceable?

a. Given that the potential infraction is fleeting and localised will smokers fail to comply assuming there is little risk of being caught?

b. Given limited resources, the difficulties of detection and the fact that the law addresses a public health issue will the police act significantly on enforcement?

c. What other measure need to be incorporated to encourage compliance and enhance enforcement?