[lenlorijn]

That's because they're talking about a "Dutch design manual". Not a law. So obviously local governments won't implement this if it is prohibitively expensive. It's just a suggestion.

'inch-thick top coat', they're talking about a top coat, not just the paint. To make sure the paint doesn't wear after a couple of months the entire top part of the cycling path is red asphalt. Though I doubt it is 2,6cm everywhere as it differs per municipality. But its definitely thicker than a coat of paint most of the time.