I have made some further subtle enhancements to the embankments and cuttings rendering, as I wasn’t yet fully satisfied with how it looked. I have adjusted the size of some of the embankment symbols on non-main roads, and removed fill on them. I also removed outer fill of embankments and cuttings on main roads only keeping interior fill. This makes embankment blend in a little bit better with the background, and the embankments less conspicuous. I think embankments and cuttings now work out quite nicely on highway lines (embankment=yes as tag), see for example the motorway junction between the A27 and A12 in the Utrecht map.
I only adjusted the latest new maps of the Nieuwe Hollandse Waterlinie, I did also update the legend of these maps to reflect the changes.
The Netherlands - Nieuwe Hollandse Waterlinie - Utrecht
http://www.boeringa.demon.nl/OSM/OSM_TheNetherlands_NHW_Utrecht_1_25000.zip
The Netherlands - Nieuwe Hollandse Waterlinie - Gorinchem
http://www.boeringa.demon.nl/OSM/OSM_TheNetherlands_NHW_Gorinchem_1_25000.zip