Help Make Straight Road (not dipped) Over Sunken Highway

[CRMDR 0]

I've recently returned to Simcity (4 Deluxe) and have downloaded NAM and many other wonderful.

 

In this highly useful tutorial "Sunken Highway Onramps and Offramps" (https://www.simtropolis.com/omnibus/_/simcity-4/tutorials/sunken-highway-onramps-and-offramps-r98) it shows a straight road going over a sunken highway with a beautiful arch underneath.

 

Having found the puzzle pieces noted in the tute and having tried them every which way for hours, I can't for the life of me get anything but a dipped road that first goes down the slope before going over the highway then up the other slope.  No way to fit an arch in there!

 

Can anyone explain how to make the road go straight across?  Thanks if you can!!

[rubberduck3y6 45]

The highway needs to be sunken by exactly 15m. Use the 15m hole digger lot to create the initial trench.

[CRMDR 0]

Ohhhhhhh of course!!    Thanks so much!!

 

I have such a re-do to do now, lol.

[Lost Realist 762]

Also make sure you're using the correct on-slope piece as there are 7.5m and 15m elevated networks now.