Cobble stones in large Eastern US towns. Dirt roads most everyplace else except for main street and highways which would be blacktop or concrete. No white line along the shoulder.
Badly maintained too (choose your rut cuz your gonna be in it for 30 miles, lol). The more rural the narrower the get and a lot were single lane. Passing was an experience.
Paving bricks were also used in downtown areas , maybe one signal at the intersection of Main Street N/S and Main Street E/W , (if any ), no parking signs , only maybe for emergency areas . No painted curbs !
No handicap ramps , bicycle lanes , etc.
It was when walking thru town at night was an adventure !
It was a time when you left your car unlocked and your shopping bags in the seat with the windows down .
I suggest picking up the HBO series Carnevale. It has some really good examples of what towns looked like in the 1930s. O Brother where art though is another good one.