Yes, there's a lot less traffic on US-23 from Mackinaw City south all the way to Bay City, a distance of 240 miles or 5 hours of driving at the speed limit, and there's many reasons for it. A few are that the 7 counties along Lake Huron coast that US-23 goes thru ahve lost a lot of population in recent years. 5 have lost more than 10% and are still losing. Unemployment is high, welfare and poverty is high, and many businesses have closed or are boarded up. Goggle each county for the details as wikipedia has them thru 2013 or 2014. The West Coast of Michigan is just the opposite as it's prosperous and growing in population constantly and some of the counties are growing very fast.
Another reason is that the air in summer in these US-23 counties is very different that on the West Michigan Coast. It's hotter and far more humid and also much more buggy as the prevailing winds SW, W, and NW blow the air in from over a couple hundred miles of heated land before getting to these counties. It's so much like the Wisconsin side of Lake Michigan. Hot and humid in summer and bitter cold in winter as it isn't a tempered climate like on the West Coast of Michigan. The air blowing over the West Coast of Michigan has crossed approximately 100 miles of cooler than the land by 10 to 20 degrees F which is like having natural A/C free. In winter, the now warm lake heat rises and warms the air passing over the West Coast of the State. 5 to 15 degrees difference between being on the shoreline of either the West Coast of the state or the East Coast of the state. Very well documented in many climate reports from actual studies.
Depends on what a visitor to our state wants to see, experience, or be in. Only a few of the 124 lighthouese are along this 240 mile long stretch.
I'm only trying the set the record straight with actual facts anyone can check/research for themselves. The devil's in the details.