I believe I have found a solution to this, the key is the DATE() function in mysql, which converts a DateTime into just Date:
DB::table('page_views')
->select(DB::raw('DATE(created_at) as date'), DB::raw('count(*) as views'))
->groupBy('date')
->get();
However, this is not really an Laravel Eloquent solution, since this is a raw query.The following is what I came up with in Eloquent-ish syntax. The first where clause uses carbon dates to compare.
$visitorTraffic = PageView::where('created_at', '>=', \Carbon\Carbon::now->subMonth())
->groupBy('date')
->orderBy('date', 'DESC')
->get(array(
DB::raw('Date(created_at) as date'),
DB::raw('COUNT(*) as "views"')
));