Why do Dutch truck number plates have a gap in the ‘zero’?

Some recent number plates of Dutch trucks have a gap in the top left part of the 'zero'. Example:

(source: cbr.nl)

I assume this is done to increase readability; I can't think of any other reason. It reminds me of letter stencils but the 'eight' in the photo shows that can't be the case. Dutch number plates never have vowels so it's not important to distinguish the letter 'O' and the 'zero'.