[Dilbert56]

It’s not so much to save the taxicab operators money, it’s to save those of us walking the streets from drowning in exhaust. At lunch hour a taxi in midtown will move about one block every ten minutes. The rest of the time it’s sitting there belching pollutants. Same during rush hour.

[JSteff]

The last is not exclusive or separate from the first. Make it make sense $$$ wise and it will be loved by all and used to the exclusion of other products.

Everyone wins.