Sit down kiddies, let grandpa tell ya a story (grin).
I started serious cycling (long distance tours) back around 1982 and spent a hell of a lot of time in "shared space" with motor vehicles. Then I had a nearly 9 year long stretch of not-riding-due-to-surgeries-and-recovery that only recently ended. Most of my riding has been in suburban to urban NY, and rural Virginia.
1) The absolute best, hands down, improvement made over that time was ACTIVE lighting. Blinky front, back AND SIDE, lights. We made do with reflectors, bright clothes, and the weak lights back when, but that is all nothing compared to the stuff you have now that is way brighter, runs forever on a set of batteries and will survive all kinds of real-weather.
2) Helmet technology has, for the most part, hit a plateau and stayed there. That is okay, the helmets are GOOD, they do a pretty impressive job of meeting the sometimes conflicting demands of comfort, protection, and price. Helmets now are way tougher and, in a lot of cases cheaper than anything we had back in the day.
3) Bike-Activism. In my younger days the entire concept of "bike-activism" would have barely registered beyond maybe getting a few "hitching posts" mounted so you could lock up your bike at the local library. Now you see serious, legitimate, amounts of space and resources being set aside to produce everything from "more bike friendly" routes all the way up to specific-use bike paths and trails. Sure there is a really long way to go but if you biked around Arlington, VA in the 90's you were lucky to survive the experience (especially at rush hour) whereas now they have complete bike-reserved routes.
Yes things have gotten better (in some cases almost unbelievably better) on the equipment side of things.
BUT
My observation is that current riders lack many of the "defensive biking" skills I was taught, or picked up, in my younger years. The most common failures I see on a regular basis are;
1) Failure to obey traffic signs and signals. Seriously, it's not just the stupidity of skipping signs and signals, it's also the fact that this behavior is one of the biggest road-rage triggers out there. I can't even begin to recount the number of times I've seen a cyclist glide by stopped cars, only to feel the wrath of the driver(s) once the lights change.
2) Keep your distance from the curb. Trash and debris tend to collect closest to the curb. Hugging the curb too tightly leaves you no room to maneuver or avoid. Drain covers and grates are generally graded toward the curb to assist drainage, this can suck your bike in too if you aren't careful. I try to stay at-least three feet from the curb. More if possible.
3) Make eye contact with motorists. I can't stress this one enough. If you don't see a motorist looking at you, I mean actually making eye contact with you, then you MUST assume that they don't/haven't seen you.
4) Establish your position, maintain your boundaries. Motorists have a regular habit of mentally putting all other vehicles around them "in a box" and assuming they will stay there. One of the best things you can do is to do a
mild weave a few inches side-to-side on occasion just to push out the boundaries of "the box" they have you in. Now understand I am not talking about wild swerves into traffic and other stupidity like that, I'm just talking about demanding some attention and space from others on the road. If a driver doesn't respect your boundaries and crowds you the least little bit when you do this,
STOP! GET AWAY FROM THEM! The hassle of having to re-gain momentum is -nothing- compared to getting hit.
5) Be clear about your intentions. This means the obvious things like using hand signals when appropriate, but it also means riding with a bit of confidence in a fairly predictable manner. If you miss a stop or turn, keep going until it's safe to turn back. If you are crossing an intersection or making a turn indicate with signals and body language
"I'm going from HERE to THERE!" Many of the bad Automobile/Bicycle interactions I've seen are simply because the motorist has absolutely no clue what the cyclist is about to do and then they get impatient and GO.
6) Don't pass slow cars on the right. I've also seen far too many incidents where a cyclist "undertakes" a slow moving automobile on the right, only to be caught as said vehicle suddenly makes a hard right turn when they see the street they've been looking for. Never, EVER, pass close to the right side of a larger truck, box truck, or tractor trailer!
7) Parked cars are DEADLY. I went for years without seeing someone "Doored" by a parked car (person suddenly opens door to get out and cyclist smashes into the door). Barely a week after returning to cycling I've seen a "dooring" and a close call. Stay well away from the sides of parked cars.
8) Make Noise. Calling out with your voice ("On your left"), Bells, electronic horns, hell I don't care if you put playing cards in the spokes, make some noise as you ride and understand that people don't hear things behind nearly as well as they hear things in front. Give plenty of advance notice that you are "in the area and approaching". Being considered "Noisy" is far better than what happens when you surprise pedestrians.
9) Avoid Kids, especially in groups. Groups of young, excited, kids are completely unpredictable and dart everywhere. If you can't pass with plenty of space then stop and walk by or at least drop down to a bare crawl. It's a pain, it's annoying, but can you live with yourself if you seriously injure a kid?
10) Be prudent about your speed. Sure you can go faster, maybe even 30mph or more, but does it really make SENSE to go faster? Keep your speeds appropriate to the conditions and the population around you and don't go doing a
Top-Gun "Control tower flyby" on pedestrians (that is unless you WANT to get bikes banned from locations).
EVERYONE ELSE OUT THERE IS DRUNK OR INSANE! Expect that kind of behavior and you'll be far better off than riding "fat, dumb, and happy".