It seems intuitive that truck traffic would decline on the PA Turnpike after tolls go up, but I am not sure why some people are presenting this as a problem. Less traffic congestion is good for the economy. Sitting in traffic is a huge waste of time and money.
If the issue is that people don’t want trucks using local roads to avoid tolls, there’s an easy solution – fluctuating toll prices based on the time of day.
During the busiest times you charge more, and during the off-peak times you charge less. Some delivery trucks and commuters would reschedule their trips to use the Turnpike at off-peak times in order to save on tolls, and everybody using the Turnpike during peak times would get to spend less time stuck in traffic.