In terms of carbon footprint, and although ride-share vehicles are typically newer and more fuel-efficient than the average passenger vehicle, per-trip emissions from ride-share vehicles were about 20% higher than those in personal vehicles.
The main reason for the difference is deadheading, said Jeremy Michalek, one of the study’s authors. On average, deadheading accounted for 43% of total drive time—time spent producing carbon emissions, blocking traffic, and being at risk of accidents that a person driving their own vehicle would avoid… More here.
There is always more to the obvious when it comes to climate change and green issues. I am not sure anyone can truly calculate what we need to do to improve.