Install a speed bump to slow cars down.
The solution is to install some speed bumps. However, due to the nature of dirt, this may be a problem. Building and installing your own speed bumps on a dirt road is quite simple, actually; however, it will be expensive and will require some help. The process will take at most one afternoon.
Shovel out a 2-foot wide, 1-foot deep ditch across the road. Roll the stainless steel pipe right in front of the ditch.
Shovel the sand into the pipe until it is full. Push the pipe into the ditch.
Shovel up sand to the sides of the pipe to keep the sand from exiting the pipe.