Dallas has implemented a policy giving natural gas-fueled taxis rights to jump to the head of the queue at the city’s Love Field Airport. Independent cab drivers in the city are protesting. (They also filed a lawsuit. A judge has denied the drivers a temporary injunction while the case it litigated.)
The privilege is intended to reduce air pollution in the city, and it probably will reduce air pollution a tiny bit. Likely it will motivate the use of additional CNG taxis at Love Field. Still, it seems like an awkward attempt at cleaning the air.