I'm looking for a curvable two-lane highway bridge that can be straightened.

Two-lane road (automobile) bridge that behaves like flexy 1 track bridge. Can be curved in some parts and straightened in other parts.

The newer ones behave like what you want. At some point they obsoleted kind "bridge" and now they must be kind "track". The ones with the newer format work.

I have bridges on the DLS and they are the old format, I may upgrade them as well as some more of Maddy25's Yarnish bridges if I can figure it out.

The only ones I could find with the new format are from Clam1952, here is one of them, I don't know if you can get it. It is 'Packaged' on my system, but is a build 3.5 and works on my TRS19, should load fine on your TANE installation

<kuid:425700:100931> CL Road Bridge 6.3m 04 - 0T 0L

This should work for you:

Road Bridge New 4LF Yarn Compatible Longer Fewer Suppts DES by davesnow.

It behaves like a regular road spline, not like the usual bridge spline.