Is it true that USA Cars are created a year before their model year?

I.e dodge, ford, gm, chevy, pontiac,
saturn, gm, etc

All cars are typically released in the last three or four months of the preceding year for example most of the 2016 models will be released around September of this year. It's like this everywhere in the world for all makes.

Sometimes. Most car makers make their models the next year somewhere between August and October of the current year. My car for example is a model year 2014 Ford Focus and the build date was September 12, 2014. I'm guessing Ford starts over in October because October started the new 2015 models. If a company is releasing a new model or next generation in the middle of the year they will often date it for the next year. Jeep released its Renegade in the US model either in April or May of 2015 but it wears the 2016 year model. Going back to the Ford Focus when the third generation was released it was also spring of 2011 but wore the 2012 model year. It's just depends on the company.

Hi car design teams are usually 5 years ahead of current models so more than one team working on a project so up to four teams working on different concepts for future models of car.