Have you seen these signs on the highway?  

My family lives in the Detroit area so I head home about once a month. While on my way I always notice a sign on eastbound I-94 a short distance east of the Jackson entrance ramp that says "Crash Investigation Site". WHAT DOES THAT MEAN? Did something really awful happen there? Should I brace for impact? What is happening in this area? While, according to Nittec.org a "Crash Investigation Site" sign means that..

The roadside areas provide a safe place away from the flow of traffic to allow motorists to exchange information and emergency responders to provide assistance following a collision.

Ann Arbor Observer reported that..

There aren't many of these sites in Michigan. MDOT selected this one a couple years ago after a study that included traffic congestion and available land.

Plus, believe it or not, but having these area's on a congested expressway can help the flow of traffic on the opposite side of the road. Gawkers are not as inclined to slow down and see what is going on.  I am not 100% these area's truly work, but they do make you think and possibly slow down a bit.