On a highway of four lanes or more, the right lane in each direction is considered the driving lane and the left lane, the passing lane. Although the Iowa DOT has 695 “SLOWER TRAFFIC KEEP RIGHT” signs posted on the Primary Highway System, not all drivers notice them or understand the meaning behind the signs. Others see the signs and think it gives them the right to tailgate or otherwise endanger the safety of slower traffic that might be in the left lane.
The danger comes whenever traffic is moving at uneven speeds, especially if someone is going less than the flow of traffic in the left lane. Did you know driving too slow in the passing lane is actually illegal. Here’s the code section, 321.297.
Rhode Island’s law is very similar to Iowa’s. Here’s a news story from Rhode Island that explains the dangers. https://youtu.be/ojuFCVeP-dY
The fatality count of 144 is an increase of five from last Monday. To see statistics published daily by the Office of Driver Services, go to http://bit.ly/1QFbcyj.