At first you think nothing much has changed over the years. You may remember sharing narrow two lane, nearly shoulderless highways, up twisting mountains, and along coastal bike routes--from Washington to S. Calif.--with panniers on your bike and maybe a tiny mirror attached to your sunglasses and a Wonder light for nighttime illumination.
However, things have changed. The roads are just as narrow but there probably is four-times the traffic, trailers are wider, motorhome drivers probably are older (marvels of medical science), and young inexperienced drivers are driving bigger cars (e.g., not you old '67 VW), all while using drugs and talking on mobile phones.
The diversion of a mobile phone is something that would have been pretty much impossible before about 1990. I still remember the first mobil phones: they were as big as a lunchbox. Truckers used CBs but you always had the feeling that loggers and chip trucks were so experienced that you probably were safe even when you thought you were being sucked under their wheels.
I know it's a numbers thing and if your number is up . . . but, it really is much more dangerous as a biker on the roads today than it was 20-years ago. I know it shouldn't have to be--and not everyone has the luxury of fairly safe road bike routes that are fun to look forward to (like I do)--but, staying away from traffic as much as possible is the only prudent thing to do.
That simple reality probably is partly responsible for the surge in the popularity of off-road riding over the last 20-years.