Was riding home on my evening commute when cars on the opposite side started flashing their lights at me. about 5-6 cars were flashing so my immediate thought was a speed detection device over a crest of a railway junction. So i slow down and one more driver flashes his lights and waves frantically. As i approach the crest well below the limit there across the road was a huge aluminium ladder someone had lost from their vehicle. I shudder to think what may have happened if i was approaching that at the normal speed since it was just over the other side of the crest and would have been impossible to stop in time. In a car you would drive over the top of it maybe sustaining some undercarriage damage. On a bike it would be much worse and I shudder to think what the consequences could have been. So a big thank you to all the drivers in Spotswood who flashed their lights at me (I was the only approaching vehicle at the time) I appreciate your thoughtfulness.