It is common in the capital, and in San Bernardino where we live, that gas stations take cards. As most stations are large "chains" one would assume that the policy of taking cards would be standardized everywhere.  But this is Paraguay and there may be issues with connectivity to verify a card in certain areas, etc.. so best not to count on it.  If you have an ATM card though you can use it at just about any bank in Paraguay to get cash from your account.
Traffic here is pretty hectic, especially in Asuncion which during rush hour. But speeds aren't high due to bad roads and congestion so accidents tend to be more fender benders than cataclysmic crashes like in some places in the 3d worlds. You just have to drive defensively and pay attention. But outside of rush hour "big city craziness", traffic is pretty light.  You should remember that in Paraguay anyone can get a license if they have some money in their pocket and you are made aware of that constantly as you observe other drivers!  There appears to be two different extremes of drivers here, they're either tentative and very hesitant in their driving habits, so they can be pretty clueless about their situational awareness and likely to do some really stupid stuff with no warning. Or they are hyper aggressive, but normally just as unaware, or maybe just careless.  And these are the car drivers motorcycle (or Moto's) are in a class by themselves. They are like "parking cones" that you just try like hell not to hit.  And of course they do clueless stupid stuff with no warning too.  Guess you can sum it up by keeping in mind to drive defensively and don't expect anyone else to.  Comparisons in my opinion is that Paris traffic is worse than Asuncion and if you've ever driven in Mexico or an African or Middle Eastern country Asuncion is downright benign.
