Allow players to set the speed of units.
The units will do their best to keep that speed.
If you set the unit to speed '5' and the current terrain or unit capability only allows to '3', then the unit goes at '3' till the situation improves.
The units will do their best to keep that speed.
If you set the unit to speed '5' and the current terrain or unit capability only allows to '3', then the unit goes at '3' till the situation improves.