Country riding on a two-lane straight high-speed highway, with or without bicycle lanes or shoulders is the place where CyclingSavvy strategies have their least impact. Drivers are most easily distracted or become drowsy on these monotonous roads. State Road A1A between St. Augustine and Jacksonville is one such road, where three CS graduates have asked me how to protect themselves.
In my view, the best defense there is a high powered, red flashing taillight. I have a Serfas Superbright Usb rechargeable taillight. Most of the time I use Lo-flash which is brighter than most bicycle taillights. On high speed country roads I have it on Hi-flash; it makes drivers want to move over well back. I also use it when solo on multi-lane highways with speed limits above 35 mph.