Secondhand smoke (SHS) is a harmful mixture of over 4000 chemicals released from the burning of a cigarette. It has been classified as a Class A carcinogen and exposure to SHS has been proven to be related to negative health effects in humans. Children exposed to SHS are more susceptible to negative health effects because they have higher breathing rates and immature, developing bodies. SHS has been associated with many childhood diseases, including asthma, inner ear infections, and pneumonia. SHS exposure in confined areas, such as inside a motor vehicle, is of concern due to the increased toxicity level of the SHS. The purpose of this cross-sectional study was to assess the factors associated with those who smoke in a car containing children and to determine if the estimated prevalence of those who smoke in a vehicle with children has decreased since legislation was passed in Farmington Maine in 2008. Observations were taken at different times of the day and in different seasons. Each observation period consisted of a pair of researchers whom stood at the edge of the roadside, at 7 observations sites located throughout Farmington, Maine. When a vehicle passed, they would first estimate if there was a child aged 13 or younger present. If so, the researchers recorded the child passenger(s) estimated age(s), and the adult passenger(s) estimated age(s), gender, and smoking status onto a preformatted observation spreadsheet. If there was more than one passenger in the vehicle, each passenger's age, gender, and smoking status was entered onto the form. Site locations were chosen based upon ease of observation and neighborhood characteristics that were used as a proxy for socioeconomic status (SES) to the location. Adult data (n=3937) were used to calculate the estimated prevalence and factors of violation. Of all adult observations, 8.26% were observed smoking in a vehicle containing a child, 63.38% of which were male. The estimated prevalence of those smoking in a vehicle containing children decreased from 13.08%, when the law was first enacted in the fall of 2008, to 7.40% in the fall of 2010. Smoking in vehicles containing children was observed more frequently at sites that were estimated to have a lower SES near them and at a tobacco store location. In the final model, gender was found to be significantly associated with smoking in a vehicle containing a child, with males having increased odds of violation. Date was found to be significantly associated with violation, with odds decreasing over time and between seasons. Site was also significantly associated with smoking in a vehicle with a child, where estimated lower SES sites had higher odds of violation. The change in prevalence between dates indicates that smoking in a vehicle not only decreased over time, but also that season could have an effect on smoking in vehicle containing children behavior. These results could be useful to those who are seeking to employ similar smoking in vehicles with children legislation, and help to improve current legislation.