Final answer:
While the mandatory seat belt law is designed to lower fatalities, the increase of overall traffic fatalities due to such legislation is unlikely and counter to the majority of research, which shows that seat belt use tends to reduce both fatalities and serious injuries.
Step-by-step explanation:
The question pertains to the unintended consequences of a mandatory seat belt law potentially leading to more traffic fatalities. Such a scenario could theoretically occur if drivers, feeling safer due to the law, engage in riskier behavior, a phenomenon known as risk compensation. However, the premise that a seat belt law, which generally reduces fatalities per accident, could increase overall traffic fatalities is counter to the bulk of empirical evidence. Seat belt laws usually lead to a net decrease in traffic deaths and injuries, as seat belts reduce the severity of injuries when accidents occur.
To directly answer the question: It is highly unlikely for a mandatory seat belt law to raise the number of traffic fatalities. The overwhelming majority of studies and statistics show that seat belt use saves lives and that mandatory seat belt laws contribute to this positive outcome by increasing seat belt usage among drivers and passengers.