One of the quirks of trailer boating is that an outboard protrudes well aft of the trailer lights with the drive tilted up. A tailgating motorist might not stop soon enough and could strike the engine. To help ensure others are aware of the protruding engine, I add a red towel to the lower unit. I attach it by running the bungee cord for the transom saver through a large grommet in the towel. If that does not seem like enough of a warning, you can buy the Davis Prop Sox (about $11). Bright, reflective orange/red protectors slide on to the propeller blades to increase visibility and reduce the chances of being rear-ended while towing your boat day or night.