Another really fun one, though slightly less literal than L/100km, is charging rates in electric vehicles, which often present charge state as range (km), rathe

Another really fun one, though slightly less literal than L/100km, is charging rates in electric vehicles, which often present charge state as range (km), rather than energy stored (kWh); and so if it takes you one hour to gain 300km of range, well… you were charging at a rate of 300km/h. (With in-flight refueling, you could potentially refuel an aeroplane at 300km/h at 300km/h…) Related: Uncanceled Units <https://xkcd.com/3038/ https://xkcd.com/3038/>. (“50 gallons per square foot” especially is similar to your L/100km: volume ÷ area = length.)