Final answer:
An idling truck uses about one gallon of diesel fuel every hour.
Step-by-step explanation:
An idling truck uses about one gallon of diesel fuel every hour.
According to the information provided, typical big rigs on the highway achieve a fuel economy between 6 miles per gallon and 8 miles per gallon. Since the question specifically asks about idling trucks, we can assume that the fuel consumption rate would be on the lower end of the range. Therefore, it is reasonable to conclude that an idling truck would use about one gallon of fuel per hour.