Also, when you put the hives in the car, orientate the hives so the frames run lengthways, along the lengthways direction of the car, so that when you brake and accelerate, they do not move much. Does that make sense? If you put them "across" the car, they flap about. Consider using a spacer board to hold the frames really tight in the hive. They use water, to keep cool, by evaporating it, which sucks the heat out the hive, thats why misting with water is so beneficial. For this to work, they do need a travelling mesh on top, for air circulation. You could also keep the air-conditiong at a low temeperature, and wear a jacket in the car?