Lawrenceburg Indiana built an elevated westbound U.S. 50 that looks to be steeper than what the pictured straight connector would have been.Also check out the “ramp in the sky” I-465 to east I-74 on Indianapolis southeast.
Freeways will typically be designed for a maximum grade of 5% even in mountainous areas. That means the road will need 100 feet of horizontal distance for every rise of 5 feet in the elevation. That means you need 400 feet of horizontal distance to get 20 feet up in the air, and that doesn't even include the transition curves at either end of the grade where the road flattens out.
Look at that photo closely, and you can see that it is a very tight arrangement. The vehicles are large compared to the aerials I saw of the two locations you described.