Been in Puerto Plata 12 times, i am a very good defensive driver, but no way i would rent a car and drive there. I think i would feel like a target $$$$$
I've learned to avoid the centre of Puerto Plata and use the malecon road to get through on my way to Costambar, Imbert, Luperon, etc. Especially during busy periods. They finally installed a median to control vehicle integration as you exit the malecon street and enter the main road through Puerto Plata. Still crazy there but it helps. Once I get to Maimon, I start to relax. I'm totally relaxed driving in the country and I avoid driving there at night.