So I gathered a little basket of car toys and each time he gets into the car I tell him he can have a toy if he gets strapped in. He usually stops the fight and waits to be offered a toy. Once strapped in I grab two toys and hold both in front of him allowing him to choose one of them.
It took a few days for him to learn this, but now he expects it and knows it is coming. I usually show him two and then he studies both looking at one and then the other trying to make the best decision that would suit him for that car ride (he does this every time, it is pretty funny). Well he studied the first and then the second and instead of grabbing one he looked up at me and shook his head no. It was hilarious. I then grabbed two different toys, offered them and he looked up with a smile, grabbed his favorite and began to play.
Do I need to be worried? No, I think all 16 month old's think they know what it's all about.