Is part of the windshield effect just that cars are more aerodynamic

Insects have been disappearing, they are something like 80% less common now than they were just a few decades ago.

There is something called the windshield effect, which means as recently as the 90s people remember their car windshields being full of dead bugs. Now that rarely happens.

Part of that is that there are fewer insects, but someone mentioned it could be due to cars being more aerodynamic now. Instead of hitting the windshield, they fly over or around the car.

Is there any proof of this?

Josef Settele made experiments with less aerodynamic off-road vehicles and found that they still gather a considerable amount of insects. If you want to dig through his publications, it’s probably in there somewhere.

It’s probably part of the effect, but people with vintage vehicles have also reported a drastic reduction in dead bugs, plus the reduction has also been shown by other insect sampling methods.

The car hits are more widely reported because that’s something people can see for themselves, rather than it being the major data source.

Or perhaps insects have evolved to become smart enough to stay away from roads :wink:


In Germany:

“Our analysis estimates a seasonal decline of 76%, and mid-summer decline of 82% in flying insect biomass over the 27 years of study.”

There are links to this and other papers in this pop-science article:

I was at a natural gas vehicles conference a few years ago and a guy who had converted class 8 trucks to NGVs said he tested their aerodynamics with a “redneck wind tunnel”, which meant he drove it and counted bug splatters. So there are bugs to splatter if you build it to splatter.

But I think insect surveys are conducted other ways. I vaguely recall something about netting tall grass back when I worked for an environmental engineer.