These are anecdotal, but I have the same experiences in North America of inspect splatter when I was younger versus the last decade, of which there is very little.
Different vehicles maybe? A day-long summer ride through the countryside on my motorcycle and my helmet, jacket and windscreen will be completely covered with bugs.
Has anyone considered this idea? That modern computer-modeled and wind tunnel tested cars are just dramatically more aerodynamic than the insect-killing cars of our youth?
It's very pleasant to be able to go for a whole-day bicycle trip and not get any insects in my mouth. But even if cars have grown more aerodynamic, I don't think I can thank the car manufacturers for this pleasant development.
In the 1980/90s I used to cycle everywhere as a kid. I must have done at least 10 miles a week as I lived 3 miles from my best friends. And I lived in the country.
I only ever remember swallowing an insect twice. It probably happened more, but it definitely wasn't a regular occurrence and tended to only happen on hills when you were going really fast.
Also the having to clean screen thing was a thing that happened certain years, not every single year. We used to go on trips to France that we drove to, from East England to France, 10 hours of driving, and some years it needed cleaning a lot, some it didn't.
Again, I totally realise that there definitely is something happening, but the way people are talking is that there used to be a swarm of insects every year, when that wasn't the case. It was different year to year, and it looks like 1989 in Germany was definitely a 'heavy' year and not a great baseline.
I think the reduction in aerodynamic drag mostly relates to the flow of air at the back of the car, to reduce the low pressure area.. so wouldn't change what's happening at the front too much. Also, since the 80s, improvements have been minor(?), and besides, road speeds have possibly increased, which you would expect to increase the incidence of squashed bugs.
