For the purpose of giving all vehicles (including the ones being guided somewhat between the lines by someone who’s mostly texting, but occasionally glancing up at the road) behind me the full benefits of depth perception, I have a semi-bright steady light at the bottom of each seatstay, and a bright steady light right under my saddle.
Similarly, I have a pair of bright lights just inboard from my brake levers on each side of my handlebars.