Music autoplays when I plug it into USB in my Acura TLX

I have an iPhone 6 running iOS 9.3.1. Every time I plug my phone into the USB port in my car, it starts autoplaying music beginning with the first song in my music library. I need to find a way to get this to stop. During an iOS beta recently it stopped doing this (I thought they had fixed this) but then in the final version it was back. Does anyone know how to get this to stop? This can't be by design as it's a major annoyance.