On the right side of the 2018 dash , when scrolling through the windows , we find three trip gages . One is for trip A , one is for trip B , and one is for over all . All three have the same format . In the center there is gas pump . To the right of the pump there are two horizontal lines . The top one is labeled "inst" for instant , The bottom one is labeled "avg" , I would guess for average . My question is what does this thing do ? It ends with "70" and the bar never changes . the top one changes with your instant mileage , but the bottom one does nothing . Can any one help ? How does it work ?