Back in package car had a route in the hood on the news weekly for homicides, so for fear of being robbed or shot sorted in back with the doors closed. Earlier driver was robbed hog tied and shut in back luckily not on a hot day, could have been fatal. On hot days drake over 2.5 gallons of water never once had to visit the restroom. Noticed other package cars had fans in them so asked them how come they have fans, they said just to write up a request in the DVIR, made world of difference. In feeders now, got stuck shifting on 103 degree, 120 heat index day, shifters have no a/c. The shifter/bird was just as hot as the back of a package car sitting on top of a giant engine operating at 180 plus degrees heat rises after all. Like stated earlier a/c in package car would only really help on trip out and back, same concept with feeders. Drivers with road runs benefit as they are in the tractor long enough to cool down. But in town drivers are in and out too often for it to cool the cab much, but knock down the heat from the from the 180 plus degrees engine. Unless you leave the tractor running, however the onboard computer keeps track of idle time and excessive means discipline, as they look at it as your stealing especially with high fuel cost. Put digital thermometer in tractors cab that keeps track of max high and low, reset at beginning of shift registered high of 193 degrees with a/c running max whenever the engine was running. A/C performance may vary from tractor to tractor. Not trying to say or pretend that heat is as bad in feeders as in package car just provide a little insight. It's kind of like the drivers that deliver shopping malls and large buildings with a/c most the day some are luckier than others. On final note it was the hottest month of July on record here since the "Dust Bowl" 1936.