Where the money actually goes
A vehicle dynamic assessment is about what a vehicle can do on the approach: the speed it can reach, the angle it can arrive at, and where it ends up. The product in the ground matters far less than the levels, the geometry and the distance the site gives you.
Rated bollards are the expensive answer because they are the answer that assumes the site has done nothing to help. Where the landscape, kerbs, planting and street furniture already limit approach speed, the specification can drop by a rating band or two, and sometimes the rated product disappears altogether.
For a town centre on a fixed capital budget, this is the difference between a scheme that can be delivered and one that cannot. Get the assessment done while the levels are still on paper.