Once, I was on a very quiet interstate, and despite having two free lanes, some guy insisted on riding my bumper. I took my foot off the gas and let myself coast. It became a game. How slow could I go before he finally passed me? It finally worked once I’d drifted down to 35 mph (that’s about 56 kph). I laughed as the guy realized how absurdly slow we were going and passed me.
It was fun, but remember not to try it on a crowded road, gang.