People often dismiss (speedway) oval racing as just turning left and it really seems like nothing more than an admission of ignorance of how much is actually involved with just turning left at those speeds.
Anyone can drive fast when they've got room, once you're all bunched up and in each other's way things get more difficult. You don't really have the choice to not be bunched up either since you go several mph faster when you remain bunched up.
If you step out of position when following someone at those speeds the wake of the car you're following can seriously upset your car. At those speeds the cars each displace a lot more air than a big truck does at freeway speeds (and most of us have felt how much air a big truck displaces when it passes at highway speeds). The cars are moving at the same speeds as an EF4 tornado, that should give a good idea of the forces at play.
Road courses usually only have one line, sometimes they'll have the odd corner that allows for multiple lines but overall they'll have one line to follow. Because the (sustained) speeds are lower on a road course downforce is a bigger deal which means generally you go faster in clean air rather than while drafting. All this means cars end up strung out pretty early on and rarely end up staying two-wide for long. In road racing a sustained two-wide battle for position just allows the cars behind that pair to gain on them, which means they're quite rare in practice.
Road courses are obviously more difficult to initially learn, but once you've figured out how fast you can enter the dozen or so corners it's easy to memorize them by rote. That said, very long road courses like the Nordschleife can be quite difficult just due to how long it can take to memorize 154 corners. A more typical 3 - 8 km road course with 12 - 24 corners isn't much of a challenge to commit to visual memory in an hour or so.
On speedways and superspeedways there's usually a top groove and a bottom groove and sometimes a middle one as well. This means cars can lap with similar times while racing side by side. This means you usually end up with two trains that both need to stay coherent in order to be faster than the other train while also being made up of cars that might benefit by jumping from one to the other, as well as breaking up the coherency to gain a competitive edge. Getting stuck in the middle can leave one suddenly losing speed compared to the two main pelotons but it's also a risk you have to take when competing for position.
Shorter ovals involve slower speeds and usually the staying bunched up is more a matter of lack of space rather than strategic benefit. Since downforce might matter more than drag suddenly the game becomes to navigate around disturbed air, rather than trying to stay within the disturbed air. Navigating traffic becomes the other main consideration. Short tracks might be their own discipline distinct from speedways though, even if they're both types of ovals.
Oval racing requires a lot of patience and strategic thinking that road racing just simply doesn't. Road racing is literally just
go fast, don't break the car. Accomplishing that same thing in oval racing is a lot harder. The closer you are to other actors the more their decisions/misjudgments can impact your outcomes and oval racing forces you to remain closer to other actors for much longer periods than road racing. In some regards it shares this with bicycle racing more than other motorsports.
TL;DR: Oval racing is harder than road racing. Change my mind but please speak from experience rather than with clichés.
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