To help reduce the health risk of secondhand smoke to children, on Oahu smoking is now prohibited in vehicles when children under 18 years old are present. Smoking with a minor in a vehicle has been outlawed on the island of Hawaii since 2010 and on Kauai, smoking in a vehicle with a minor younger than 13 years old has been banned since July 2016. Legislation is currently pending for Maui. Smoking is defined as exhaling, burning or carrying any lighted or heated tobacco products, including cigarettes, cigars, pipe tobacco, snuff, snus and even applies to all electronic smoking devices.
According to the Honolulu Police Department, drivers who are caught breaking this law are required to make a court appearance and may be subject to fines of a maximum of $100 for a first offense, $200 for a second offense within a year, and $500 for a third offense.
Source: Center for Disease Control and Prevention, American Academy of Pediatrics, healthychildren.org