I can only find one other source for this news and there's no press releases that I can find. Perhaps someone with access to advertising trade journals could dig something up?
Edit: got it - http://gmauthority.com/blog/2018/09/gm-studies-drivers-radio... - The automaker’s director/global digital transformation, Saejin Park, said at the Association of National Advertisers’ (ANA) 2018 Data & Measurement Conference that the new insights can help serve up better ads.
https://www.warc.com/newsandopinion/news/general_motors_gene... won't load for me.
Edit: got it - http://gmauthority.com/blog/2018/09/gm-studies-drivers-radio... - The automaker’s director/global digital transformation, Saejin Park, said at the Association of National Advertisers’ (ANA) 2018 Data & Measurement Conference that the new insights can help serve up better ads.