>Before any new car hits the showroom, the EPA runs an emissions evaluation and calculates a “CO2 equivalent” – a single number that represents GHGs CO2, NO X , HC, and CO. The CO2 equivalent units are in grams/mile, so a higher number means more GHGs and more climate damage. For a 2WD 2020 Ram 1500 HFE on the highway, that number is 340 g/mile. Unfortunately, motorcycle emissions data isn’t documented by the EPA. This is a real issue, because if the problem isn’t measured you don’t know what to fix.
>There are a few independent studies that shed light on the issue, however. One published in 2008 by Swiss researchers took real data from several motorbikes including a BMW R1150GS. The GS highway CO2 equivalent is a stunning 380 g/mile (17% worse than the Dodge)! They found that a 1993 Honda Shadow VX600 with only 583 ccs spews a whopping 408 g/mile. That is twice as much as a new Honda Civic!
>Other studies would suggest the problem is even worse. Global MRV tested out their portable emissions equipment in 2011 comparing 12-motorcycles to 12-cars of varying years (this was featured on an episode of Mythbusters). Motorcycles were almost universally terrible, with motorbikes from the 2000’s producing 3,220% more NOx and 8,065% more CO2 than cars of the same era. California has the largest motorcycle ridership in the country, and in 2008 the LA Times reported that while motorcycles accounted for 1% of all miles traveled, they were responsible for 10% of the state’s smog-producing emissions.
Taken from https://autowise.com/motorcycle-vs-car-emissions/ .
I've had my M1 since 1994, so I enjoy riding, so please don't take this as all negative. But it's important to look at the real data, which is much worse than people think with regards to emissions and pollution.