This ramp is an asset of the Utah Map. Yes, you can place it using World Editor. To do that, enter World Editor using F11. If you can't see the asset browser, add it by clicking on the window button in the top left (see red circle in image). In the asset browser, navigate to art>shapes>buidings and search for "ramp". Select the ramp you want to add. Drag and drop it to add it to the map. You can then move, rotate and scale the ramp by using the red, blue and green indicators and the buttons 1, 2, 3. This only works on Utah, as this asset is only available there. But there are other ramps you can use on most other maps. Here's a screenshot of me adding the ramp and a car using it: I hope I was able to help