The given graph shows how speed can affect emissions of nitrogen oxide produced by four different vehicles.
Overall, it is evident that disel and petrol car relatively emit an unchanging amount of nitrogen oxide regardless of speed, while the opposite is true for busses and lorries.
Busses and lorries have rather varying nitrogen oxide emissions depending on how fast they travel. The figure for bus emissions starts at 40g/km with 10 KPH of speed, then hits an absolute low of 25g/km at 60 KPH, and the figure makes a recovery back to 40g/km as the speed reaches the limit of 130 KPH. The figure for lorry emissions also experiences a similar trend, starting at 33g/km at the same initial speed, later steeping to 15g/km at 90 KPH and eventually slowly recover to 25g/km at 130 KPH.
Regarding the nitrogen oxide emissions for diesel and petrol cars, their figures are rather stable no matter how fast the vehicle travels, at approximately 5g/km and 12g/km respectively.
