Gas is popular in Oz
In Australia, the stuff you call "gas" we call petrol (is is a liquid not a gas after all). We also have a lot of cars that run on real gas, specifically liquified petroleum gas or commonly called LPG. The reason for this is that it sells for around half the price of petrol or diesel. You would have difficulty finding a taxi here that does not use the stuff. It is also favoured for lower exhaust emissions. The disadvantage is that the car needs to use about 20% more to travel the same distance and power output is usually slightly less. Boot (trunk) space is also taken up by the pressurized cylindrical "gas" tank which also usually offers a smaller range between refills. The tank also cannot be completely filled as a vapour space is required above the LPG which, as the name suggests, is in a liquid form at pressure in the tank.
LPG conversions are popular on commercial vehicles and our locally manufactured medium and large cars. Most of our taxi fleet are local Ford Falcons and Holden (GM) Commodores with LPG. Some privately owned vehicles have been converted, especially where the owner covers high annual mileages thus justifying the cost of conversion.
Not many Mercedes have the conversion although some of the earlier "thirsty" V8 and six cylinder models (mainly W116 and W108) were converted. Commonly seen gas powered Mercedes here are our Sydney buses. Sydney's government run bus fleet is, I believe, the largest outside Germany. We have had predominantly Mercedes buses here for well over 20 years now and many of the latest generation run CNG or compressed natural gas rather than diesel. I understand that they are a modified version of the diesel engine fitted with spark ignition which allows the use of natural gas, a very "clean" fuel.
107.023: 350SLC, 3-speed auto, icon gold, parchment MBtex (sold 2012 after 29 years ownership).
107.026: 500SLC, 4-speed auto, thistle green, green velour.
124.090: 300TE, 4-speed auto, arctic white, cream-beige MBtex.
201.028: 190E 2.3 Sportline, 5-speed manual, arctic white, blue leather.
201.028: 190E 2.3, 4-speed auto, blue-black, grey MBtex.
201.034: 190E 2.3-16, 5-speed manual, blue-black, black leather.