Sailing in an archipelago like the one in Stockholm, up in the map, can be really complicated, due to the infinite amount of straits and “junctions”. We had never before seen real “driving signs” at sea, and there is no doubt that they become really necessary in this situation.
AIS seems to be the perfect tool in this environment, due to its independence from meteo conditions, and because land stations can send signals that can virtually draw on your plotter indications, signs, etc…
Besides, the VHF signal can go through obstacles such as capes, islands, which lets you detect AIS contacts before you actually see them, and thus helping you to avoid possible colisions, that with a radar would be completely impossible to prevent from happening.
Below, a sign in an island indicating where you should go through depending on the kind of boat you are piloting!