All this yap about "get a big vehicle. Not certain if many of you get out much, but I have logged 115,000km over the past 2 years driving all over the country... point to point to point. I have not seen many of those huge potholes some speak of. Sure, there are a few, but the same back home. I don't just stick to the main roads either. Yes, if you are off to the campo in the mountains, an SUV is best. But for everyday driving, do not expect to loose your car in a hole. BTW...the most common vehicle I see flipped over on the autopista..big SUV's.
I've driven all over the country for the past 10 years. While I have also traveled long distances in a sedan occasionally, I do not prefer that in any way. Not sure which country you are from as you say that "sure, there are a few, but the same back home"... I'm European, and the quality of DR roads and the roads in my country is like night and day.
On the same mentioned Autopista Duarte, there were just up until a few months ago (I think), these huge repetitive potholes on the bridges crossing La Vega. I saw them always and made corrective movements, but I can only imagine how does a small vehicle react when it hits those holes at 50-60 mph...
Also what Garyexpat already said, it's not just the the potholes, it's the open water drainages on every street corner, blocked drainage spitting all the filthy water to the street... Just in June, I was in HOMS with my wife, we departed for Puerto Plata in the afternoon, in a heavy rain, and went through the circunvalacion. I saw some sedans stuck in the water, while we, with our full-size SUV as you would call it in the US, got home safe, dry, and quickly...
I too, only prefer large vehicles in the country, as another reason for this is to be slightly above of the headlights of at least some of the other vehicles, so that you see better forward in dark. Bear in mind, in my country, SUVs and more so full-size SUVs with V6 engines and above, are unheard of. Only small sedans, station wagons and other vehicles that consume almost zero gas. Then again, as said, the roads in my country and the DR do not compare in any way. Nor do the drivers.