Automobile's access to my Contacts?

In case anyone is curious, the answer is a setting in the iPhone. Go Settings>Bluetooth>(name of automobile>("i" in circle)>Sync Contacts. The trick (that I still do not understand) is manipulating the bottom of this page. After I turn on "Sync Contract," the iPhone automatically chooses "All Contacts." After I de-selected "All Contacts," the iPhone chose exactly the one group of contacts that I most wanted to NOT show in my car. That group duly appeared in my car. After several more efforts at unpairing and re-pairing the car and the phone, I was able to de-select in the iPhone the undesired group of contacts and choose the one group that I do want. The undesired group continued to appear in the car. I gave up for half an hour. When I went back out and turned on the car, the correct group of contacts appeared in the car, and the undesired group did not.

What I see in my car's dashboard are all the contacts in my Contacts application. Almost all of those contacts are ones that I typed in manually over the course of the last thirty years. Two or three came from vcards that I imported. None of these contacts come from any emails. I am not aware that Contacts has any association with email accounts.