Rivers and creeks were dammed, sometimes in multiple places, so logs could be driven downstream. Some of dams were permanent, and some were built and then destroyed for the log drive. Constructing a dam safely was not easy—in addition to felling, floating, and stacking the timber, the loggers had to work in and around fast-moving water. Drowning was always a risk.
One benefit of a logging truck? It would go anywhere a road could be built—and you didn't even need to lay down track. Float the logs to the dam, load up the truck, and hold your breath as you went back over. In this case, it was probably better to be in the truck cab than working downstream.
The log drive remained a good way to get timber to the mill long after steam donkeys and logging trains were a thing of the past. But it never got safer; driving logs downstream was one of the most dangerous jobs in the industry. And it all had to be done while water levels were high, so the drivers were always working against the clock.