In looking at the CMF for Increasing Intersection Median Width in Part D, Table 14-17, the question came up about the treatment of increasing intersection median width by 3-ft increments. This can imply that you can multiply the CMF for every 3 feet, so if you start with a 14 ft median and add six feet at a rural, four-leg unsignalized intersection (CMF=0.96) can use a CMF of 0.96*0.96, so a CMF of 0.92 could be used? Could this be done all the way up to 80 feet? (this doesn't seem quite right, as it would give a CMF of 0.41)

I would appreciate any suggestions on how this CMF is intended to be applied. Thanks!