I wish I had the know-how to make a script that looked at all Asphalt in a radius of any "bumps" and did a quick calculation to "smooth" out said bumps
Example: road going through the desert, there are 200 blocks of asphalt in a 4 wide by 50 long stretch, all at height 100 (60~ rock/ores and 38 sand/sandstone and 2 layers of asphalt) and in column 2, 8 blocks in from the bottom (left) there is a 1 block discrepancy making a single "bump"
the script would "follow" the roads on asphalt only and when it discovers a "bump" it checks the closest 5-6 other asphalt blocks and changes the single/double block bump to match the height of the others in the area (if the closest are more BELOW as in an Asphalt spire happened, it would halve in size as the lowest of the check and the current top would have a calculation split the difference)
simple diagram
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the script in my perfect would would look 1 in each direction (NESW and Up and Down for a total of 6 checks) and would look at each one's height data and emulate it to smooth out roads
Of course this is probably a HUGE waste of time, and probably WAAAAYY more complicated than this, but one can dream, right?
anyways...motorcycle needs paints and a noise/heat increase, 4X4 needs lifted chassis, Bicycle should coast on hills with gravity increasing speed like gravity would