In terms of the majority answer, there is a clean break between the three automobiles and everything else. This is what's known as "having common sense". It is this common sense that leads the majority to answer that a bicycle is not violating the rule. Is that because they believe, in their heart of hearts, that a bicycle is not a vehicle? Could it truly be that 55% of people don't know what a vehicle is? Or is it because they are capable of inferring from context that vehicle was an imprecise supertype and the rule clearly referred to subtype automobiles?