Before beginning a long drive, which item is crucial for fuel efficiency?

Proper tire inflation is crucial for fuel efficiency because it directly affects the vehicle's rolling resistance and overall handling. When tires are inflated to the manufacturer's recommended pressure, there is less resistance when the vehicle moves, which means that the engine does not have to work as hard to propel the vehicle forward. Under-inflated tires create more drag, leading to increased fuel consumption.

Conversely, over-inflated tires can also be problematic, as they can lead to uneven wear and reduced traction. Therefore, maintaining the correct tire pressure is essential for maximizing fuel efficiency and ensuring safe driving conditions.

Other items listed, while they may contribute to comfort or vehicle performance in different ways, do not have the same direct and significant impact on fuel efficiency as proper tire inflation does.