Development costs for feasibility analysis of building land

In the reasoning, a passage about the costs of development can be found. It states that development costs including the planned road are only charged up to a certain rate.

Is it possible to convert something like this to today's time adjusted for inflation and currency?

Is it possible to convert something like this inflation- and currency-adjusted to today's times?

With an "accuracy" comparable to weather forecasts, yes and no.
More has happened since then than just the introduction of the euro: we have a single market, fiber optics were not an issue back then, but today gas hardly is anymore. The pedal boat quickly gets into trouble if you try to roughly estimate it from there.