Is there an official answer whether you can move onto the bridge hexes from every surroundig hex or not?

Some people play it that you can only move onto a bridge from adjoining roads, some people play it that you can move from every hex onto a bridge...I think from only adjoining roads were more logical.

There is no general rule limiting where a unit can enter a hex containing a bridge from.

Now, as for the cost to move into that hex, it would be related to the base terrain type which is stream. So depending on the stage of the stream and the type of unit that would impact your movement when not moving from an adjoining road hex. So for example, if the stream were flooded then you could only move onto the bridge hex from the road since flooded is impassible to all units. Best to think of a bridge in the same way you think of a road through a wooded hex.

Actualy I think that a Bridge hex is a seperate type of Terrain, not just an overlay on the stream beneath it. This would mean that you can move onto the bridge Hex from any hexside at the cost of 1 MP, even from another stream hex. Not very realistic, I grant you. The only rule that Bridges have is that they have roads printed on them that Are continous to the ajoining roads, and thus lets trucks use the lower movement cost.

That's fair. I think I made a false interpretation in reading the note saying that it counts as a road hex is so far as it relates to contiguous movement and not to the other part about the road hex and the underlying terrain.