why lorry 3.5-7.5 make more emission than lorry 16-32?

Question

I created two processes using the two flows Lorry 3.5-7.5 and Lorry 16-32 considering the same Km both.

I got more emissions from lorry 3.5-7.5 as a result.

I think I'm doing something wrong. Do you have any advice?

Answer 1

Not looking at the datasets, but per tonne-km, the larger lorry is probably more efficient and thus it makes sense that the smaller one has higher emissions?