A step-by-step on how to create 3d sawtooth curbs. For Simon.
Preparation: Have your basic shape and mapping for the curb done. One segment is enough, we will replicate it later.
1. Create a shape on the edge of the track where you want your 3d curbs to be. Either manually create the shape or create it from the track border. One shape vertex at each vertex at the track's edge. Make sure they are all set to be of the "corner" variety.
2. Measure that shape to know how often we must replicate the curbs. In this case it's nearly 60m of curb we're going to need.
3. Get your basic curb shape. In my case the bottom ones are the more detailed ones with drainage, the row above is without drainage and the single one at the top is my original mesh. I use directionally different curbs, hence left and right side versions.
4. Copy it over somewhere close to the place you want it for convenience. Then select the Array tool.
5. In the Array tool, set the x displacement to the width of your curb segment (2.5m in my case) and for the number of segments you need to fill that shape (24 in my case).
6. Tada! Collapse them into a single object.
7. With the collapsed object selected, select the PathDeform (WSM) modifier.
8. Click Pick Path and select the shape we created under 1.
9. Set Path Deform Axis to X. If needed, you might need to either check the "Flip" option or use the Rotation option (usually with a value of 180 to have the curbs oriented the right way). Click on "Move to Path" and move the curbs into their position by either modifying the objects x-coordinates at the bottom (or in the F12 box) or using the Percent option of the PathDeform modifier.
The technique is basically the same as in the "Creating Curbs using WSM PathDeform modifier" video tutorial available here.