There are two kinds of improvements, those of the land itself (like a new road or a water pipe etc) and those like houses or businesses. LVT directly includes the former, as they would be included in anyone's assessment of value (whether that be a government assessor or the owner). However, the value of the land is also
indirectly linked to the improvements like houses. If you make a piece of land more productive by building on it then the land itself becomes more valuable, as will nearby land.
So with either kind of improvement the tax can go up, but LVT still encourages development compared to property tax as undeveloped land will still attract a greater proportion of tax than it would under a property tax.