The graph illustrates the nitrogen oxide emissions from four vehicle types—diesel cars, gasoline cars, trucks, and buses—across varying speeds ranging from 0 to 130 km/h.
Overall, it is evident that each vehicle type exhibits distinct patterns of nitrogen oxide emissions, with gasoline cars consistently emitting the least, while buses show notable fluctuations.
In detail, diesel cars begin their emissions at approximately 40 units at 0 km/h, displaying a slight decrease to about 37 at 50 km/h, before increasing to about 45 units at the maximum speed of 130 km/h. Conversely, gasoline cars start at around 10 units, experience minor fluctuations throughout the speed range, and conclude just below 8 units at 130 km/h, showcasing their relatively low emissions compared to the other vehicles.
Trucks’ emissions commence at roughly 35 units, gradually declining to around 32 units at 50 km/h, only to rise significantly to nearly 40 units at 90 km/h, ultimately ending slightly above 35 units. Buses follow a similar yet more dramatic trajectory, starting near 41 units and plummeting to 30 units at 50 km/h. However, by 130 km/h, bus emissions rebound to just below 50 units, indicating a strong increase in emissions at higher speeds.