I didn't catch the beginning of it, and after the first commercial break at approximately the 1/4-hour mark they never came back to the topic - except to discuss NOT making left turns - until I fell asleep at about 1:15 into the program. The show is 5 hours long, so there was still 3:45 left during which they might have returned to the topic.
What I did hear talked about was the danger of drafting. The host said he had recently received in an email photos of an accident in which the driver of a car which had rear-ended a tractor-trailer was cut in two.
He also said that UPS has a policy of not making left turns in an effort to save fuel.