I notice that the larger the truck the greater the magnitude of the lurch. Can anyone give a physical explanation to this?
Bernoulli's principle, the fast moving vehicle drags air with it creating a low pressure region. if you live in a country with high speed trains it's enough force to pull someone off a station platform if the trains don't slow down. (good explanation http://www.physics.umn.edu/outreach/pforce/circus/Bernoulli.html)