= Englisch [EN], 
= Deutsch [DE], 
= Französisch [FR]. Wenn du die angegebene Sprache nicht beherrschst, schreibe auf Englisch! So I 'discovered' an amazing way to quickly create road islands, street markings and other stuff with splines.
Use small objects, basically, as vertices (points) and then align a spline start and end to those objects with "Align To" options.
Since heavy usage of splines is sometimes discouraged - you can always export the result to X file and then convert it to an object, but what really impresses me is that it's much easier to do things on roads with gradients - since "To spline"positions object exactly at the right height. So you can create even road markings easily on gradient roads, it's just how many bollards/objects you need to make a smooth line.
So here is a quick video how I created an island (I haven't filled it) but still.
Also, here are these markings which are very tedious to make (I entered skew values for these big stripes as well, just to be clear). This way the process is 50% easier.
Positioning
The other option is that this way you can easily position splines next to the road. The only caveat is that left or right edge of the piece spline (example: sidewalk) must be at X = 0 in the spline. If X = 0 is the middle of a spline then you need to adjust the offset (so if spline is 1.5m in width, you need to position the bollard 0.75 from the spline).