Existing gasoline-powered vehicles may be converted to run on CNG or LNG, and can be dedicated (running only on natural gas) or bi-fuel (running on either gasoline or natural gas). However, an increasing number of vehicles worldwide are being manufactured to run on CNG. Until recently, the now-discontinued Honda Civic GX was the only NGV commercially available in the US market. More recently, Ford, General Motors and Ram Trucks have bi-fuel offerings in their vehicle lineup. Ford's approach is to offer a bi-fuel prep kit as a factory option, and then have the customer choose an authorized partner to install the natural gas equipment. Choosing GM's bi-fuel option sends the HD pickups with the 6.0L gasoline engine to IMPCO in Indiana to upfit the vehicle to run on CNG. Ram currently is the only pickup truck manufacturer with a truly CNG factory-installed bi-fuel system available in the U.S. market.

What's the best answer to this question: can you put regular gas in a natural gas car?
yes