There are 18 time trials tracks in this game that aren't on the leaderboard that could have tricks/trickless categories measured by in game time. IL times for championship could be nice too.

This is done in Mario Kart 64 to skip straight back to the title screen after finishing each cup, as it is faster than watching the cutscene that plays after you win. There is probably over 2 minutes of dead time in this run that could be cut out by just resetting and selecting the next league.

Why not do this? Would it be allowed in a run?

Update #2: Ignore everything here, there is no emulation problem and that explanation is incorrect. The speed boost happens when you are out of bounds and press up when a dark blue car is on screen, for whatever reason.

Update: I have figured it out. It is not an emulation issue. For some reason, when the timer reaches zero, you can push up again and will gain an extra speed boost resulting in a time of 2:59. Without the speed boost, 3:06 appears to be the best possible time. In the case of my rejected run, I held up throughout the entire run and it gave me the boost.

So my run was just rejected by NESCardinality because the car started going faster than normal after the timer reached 0. I didn't notice this whilst playing or looking at the video afterwards, but I was confused as to how times were different because the run is the same every time unless you get rammed somewhere.

This video also has a speed up when the timer reaches 0:

Can someone try and reproduce this on NES? I have no idea why this is happening.