I watched a lot of teams (both veterans and rookies) struggle with this over the weekend. I'm not sure if the issue was more geometry or providing enough torque to the bridge to lower it.
One of the most clever methods I've seen is team 103, who has two curved pieces of tubing that flip down and so when they drive up to the bridge the natural motion of their forward momentum causes the bridge to tilt and allowed for them to get up pretty easily. It was a pretty effective, light weight and passive way of lowering the ramp without having to stop and wait for some other mechanism to push the bridge down. If I can find a pic I'll post it.
Or you could try the 25 method: bump the bridge, pop a wheelie and then get on. Seemed to work well for them
