I discovered a weird cut or alternative route in Road70. If you drive the track forwards, it cuts the whole part of the tube / pipe with the blocks in it!

However, you can't reach it normally, or not how I would know, because it's on a higher level than the default road.

I attached three pictures. The first one shows a side view of Road70, the cut in red, the forwards route in blue and parts for the reversed version in green. Light blue is the starting line.
The second one would show the entry to the cut, however, marked in green, is a wall which blocks your way to it. It looks like you have to jump in there somehow, but how?
The third one shows the exit of the cut, it throws you out right in front of the circular routes where the street splits into two for a short moment. You can see that there's no possibility to jump into this cut in the reversed mode, as their is not a single ramp in the near.

Does anyone know more about this cut?

There also seems to be an alternativ route in Skyrace not normally accessible... it's near the U curve with the hill upwards. S. attachment. It was probably originally planned to have a brigde to there if you drive the outer side of the hard U turn, but it looks like it has been removed. The minimap proves my thought. You cannot jump there without cheating.

EDIT: Oh well, you can get it with a good wallride! You do not simply fall down since it's declared as floor probably. You even have to drive through the arm of the machinery laying at the one end near the side. Awesome cut...

Also you can drive on top of some roofs, where other tracks are normally designed to let you fall through.

It's really hard, but it turned out to be possible.

I chose Scorp for this shortcut, as it's one of the heaviest cars. This was done with manual transmission.

1. You try to stay on the left or the centre of the road when you jump (the first attached picture).

2. Try to land on the flat ground and then go up the sloped wall.

3. Try to go between the rocks of the vertical walls that are over the slope. I've found that the right rock tends to cause less problems with the collisions, but if that doesn't work, try going just a little bit to the left.

4. You must drive in the air. Press the left and right arrow keys when you jump again and leap for the shortcut.

I didn't change speeds at all, as you can seen on the pictures.

Hope this helps. :)

I see, Ill record that in the addendum to my videos.