It is frustrating, and I'm sure many have experienced this....2 lane hwy, driver in front is doing 5-10 mph UNDER the limit for the last 10 miles, you follow at a respectful distance, keeping your angry/rage in complete control, waiting for that passing lane which you know is just ahead, Ok, finally it's time to pass this driver, uh, no it's not, because they have accelerated to 20 mph OVER the posted limit as soon as they hit the passing lanes.....oh man....makes me crazy! Fortunately, i've taken a precausion against this by hitting the glass twice before leaving the house.....Now I'm able to accept this reality, I'm relaxed and mellow......Rage is checked.......