It depends on the car,sometimes you can hide them in plain site,my old restorod deuce sedan had cowl lights and I converted them to use as turn signals. HRP 1645-1215521051-99f039e7a9faa908d09c8449e3f9b774 by Danny Berry, on Flickr
I'm not running fenders on my coupe, so I had a dandy spot (I thought) for these: '51/'52 Chevy license lamps converted to LED.. Of course I still get grief from folks who have no idea what a flashing light on one side of the car is indicating!! Dave
Can you install them into headlamp buckets, down here we're allowed to do that so it's a simple matter of drilling a hole in reflector opposite park lamp, above or below headlamp bulb and hiding them behind the lenses? As the authorities down here are pretty **** at the best of times, it comes as a surprise when they actually allow you some la***ude when it comes to these things.