A method of controlling an air dryer system having first and second air dryers (16, 120; 18, 122) configured to receive compressed air from a compressor (14; 112) of an associated vehicle , the method comprising: monitoring a condition related to a compressor output state; operating the first and second air dryers in a first mode, said first mode corresponding to a high flow mode wherein the first and second air dryers are connected in parallel with the compressor, wherein the first and second air dryers substantially simultaneously receive air from the compressor when in the high flow mode; operating the first and second air dryers in a second mode, said second mode corresponding to a continuous flow mode; and switching the first and second air dryers between the first mode and the second mode based at least in part on the condition related to the compressor output state; wherein the operating the first and second air dryers in a continuous flow mode includes alternately drying and purging the respective first and second air dryers, wherein one air dryer is drying air while the other air dryer is being purged; wherein the monitoring a condition related to the compressor output state includes monitoring at least one of a compressor inlet pressure and a compressor outlet air flow; and wherein the method comprises: operating the first and second air dryers in the second mode when the monitored condition is indicative of a low compressor output; and operating the first and second air dryers in the first mode when the monitored condition is not indicative of the low compressor output. monitoring a condition related to a compressor output state; operating the first and second air dryers in a first mode, said first mode corresponding to a high flow mode wherein the first and second air dryers are connected in parallel with the compressor, wherein the first and second air dryers substantially simultaneously receive air from the compressor when in the high flow mode; operating the first and second air dryers in a second mode, said second mode corresponding to a continuous flow mode; and switching the first and second air dryers between the first mode and the second mode based at least in part on the condition related to the compressor output state; wherein the operating the first and second air dryers in a continuous flow mode includes alternately drying and purging the respective first and second air dryers, wherein one air dryer is drying air while the other air dryer is being purged; wherein the monitoring a condition related to the compressor output state includes monitoring at least one of a compressor inlet pressure and a compressor outlet air flow; and wherein the method comprises: operating the first and second air dryers in the second mode when the monitored condition is indicative of a low compressor output; and operating the first and second air dryers in the first mode when the monitored condition is not indicative of the low compressor output. operating the first and second air dryers in the second mode when the monitored condition is indicative of a low compressor output; and operating the first and second air dryers in the first mode when the monitored condition is not indicative of the low compressor output. <EOS>