What makes decision right

After noticing several two vehicle accidents governments bought up a new rule "Helmet wearing is compulsory for two vehicle drivers". But reasons such as hot tropical climate/weather in asia leads to excessive perspiration from the scalp, difficult to breathe from the full-faced helmets and also result in the loss of hair. so many people have started to buy four wheelers which in turn causing a lot of pollution and indirectly leading to deaths of many lives. I don't know exactly how many lives are saving by wearing a helmet but I am sure many lives are in danger with increase in pollution. So what makes decision right?