How can driving habits affect emissions?

Driving habits play a significant role in determining the level of emissions produced by a vehicle. Aggressive driving, such as rapid acceleration and hard braking, often leads to increased fuel consumption. This is because the vehicle's engine must exert more energy to accelerate quickly, leading to a less efficient fuel burn. Additionally, excessive idling contributes to higher emissions because the engine continues to run while not actively moving the vehicle, wasting fuel unnecessarily. As a result, driving styles that emphasize rapid changes in speed and long idle periods directly correlate with increased emissions, making the correct choice the one that highlights these behaviors.

The other options don't capture the complexities of how driving habits impact emissions effectively. Frequent maintenance, while generally beneficial for vehicle performance, does not inherently lead to higher emissions. Smooth driving techniques can contribute to lower emissions, but they are not guaranteed in every scenario, meaning they do not always apply universally. Lastly, driving with windows open might slightly affect aerodynamics but does not generally decrease emissions in a meaningful way compared to normal highway speeds, where the engine efficiency typically governs emission levels more significantly.