Dry pavement, nighttime. A black angus cow and calf were on the roadway, causing the whole crash. No brakes on the trailer, it was a home-made job made out of an old wooden whiskey keg. We didn't weight the trailer, but it was very heavy (I had a hard time tipping it over to look at it). Driver had been drinking, but wasn't impaired.
From the roadway markings, It was apparent that the driver made a heavy brake application, after 10 metres or so the weight shift of the trailer pushed down on the hitch, bottomed out the bike suspension, and the rear wheel locked (the hitch actually cut a gouge in the pavement). About this time the trailer was jack-knifed to the right hand side of the bike, and the trailer wheels made scuff marks parallel to the gouge and the bike's skids. The whole unit tipped over, and slid down the road on the side until it hit the cattle, then bounced into the ditch, rear first.
I did the math on this, given the known location of the start of the skids (point of perception), the known location of the cattle (area of impact), and the known friction coefficient of the road (f). There was enough time to stop safely, without hitting anything.