Part of the problem with analyzing the general capabilities/safety of drivers over time is that cars have gotten way safer, and smarter. Frontal pre-collision brake assist, automatic lane centering, radar-assisted cruise control, 9+ airbags per car, better seat belts (some that actually are airbags), brilliantly engineered crumple zones, they all substantially reduce the number of deaths per mile driven as well as deaths per accident. Plus in general, people drive greater distances on average now, and make more freeway trips, which are generally safer (read: fewer collisions per mile driven) than surface street trips. So, just because there are fewer deaths or accidents per mile driven, it does not directly follow that people are better drivers. I think people would have to be much, much,
much worse drivers today than in the 80s/90s to get fatalities per mile back up to where it used to be.
I’ve only been driving for a decade (although I’ve been paying attention to traffic for maybe 15 years?) and in the last ~4 years I’ve anecdotally noticed a very steep decline in general driving competence, across 3 provinces and 6 states. Not just distracted driving (poor reactions, unable to keep vehicles centred in lanes, etc), but unnecessarily aggressive driving (purposefully blocking merges, passing in dangerous conditions, etc), unnecessarily fearful driving (hugging the right of the lane, driving >20% below the speed limit/flow of traffic during busy times of day, braking unnecessarily early for stoplights that haven’t yet changed [or worse, for a stoplight that doesn’t apply], etc), and what I call “mindless driving” (camping the left lane while travelling well under the flow of traffic and/or speed limit with cars passing 20-40km/h faster on the right, changing lanes without checking it’s clear or even signalling, blowing through stop signs/crosswalks, not moving over or slowing down for emergency vehicles on the shoulder or approaching from behind, etc).
All of these things have been happening forever, but I’m certain they’re occurring more frequently now. I’ve had a dashcam in every vehicle I’ve owned, and I used to save clips of “idiots” every week or two when driving ~600km/week. These days I drive less than a third of that on average and I’m saving clips almost every time I drive somewhere. Just this past week, I’ve seen two near collisions involving school buses, 6 (!) cars changing >3 lanes in opposing directions simultaneously in and out of each other within 150m of multi-lane off ramp, an accessible school vehicle (wheelchair-equipped minivan for disabled students) pull out of a stopped lane into another lane in front of a car travelling at full speed (~80km/h, the posted speed limit) who had to swerve off the road to avoid it, a vehicle purposefully matching the speed of a vehicle trying to merge on the highway to prevent them from merging safely, and (my favourite) a pickup truck accelerating from ~105km/h to ~130km/h at full throttle (while previously camping the left lane of a two-lane freeway) to prevent me from moving over for a police car and ambulance stopped on the shoulder, partially in my lane, up ahead. All within ~450km (busier driving week than usual). And this isn’t a particularly notable time period, the last 2 years have been like this constantly.
Maybe I’m just noticing it more now, maybe it’s localized, but I’m very confident that drivers, in general, are worse now than they were even 4 years ago.