I started testing the stand alone bridge objects from the terrain editor to drive tanks over water ways. On my new terrain I laid down an airfield, GV spawn, and bridges to test offline, found two problems with the bridges.
Bridge object settings: elevation 0.00, can collide unchecked, set to terrain elevation unchecked.
1. - The bridges require the land on either side of the water way to be a minimum 175ft to set the slope angle to meet the ends of the bridges. Can the bridge objects properties be modified to allow a negative value for elevation so the approach angle is more shallow allowing for lower elevations near the water? As is the steep angle down will impact GV game play. The flat bridge has 5 of the bridge object 01 to make that span. If it had a sloped segment that can be added to each end that might make the angle better for GV play.
2. - The two screen shots below show that tanks stop forward motion and responding to direction inputs or reverse gear at the location up slope from the ends of the bridges. They will over a long time period eventually slowly slip down the slope to the end of the bridges. At which point the tank stops forward motion. Once during testing I was able to use reverse gear then forward to get the tank onto the bridge, but the tank would not respond to higher gears. At the other end the tank stopped when trying to mount the up slope. After that all tanks stopped at the same point up slope of the ends of the bridges during testing.
I don't know if you will accept for the Melee arena adjusting the pitch of the two end segments of the level bridge, just though of trying that.
I attached a zip file copy of the oceania.res if you need to look at those points on the terrain.