Actually, no. There is no ability to suspend analog radio broadcasting as there is for TV. Currently AM and FM radio broadcasters have the option to supplement their existing analog broadcast with digital. The FCC has not given anyone permission to cease analog AM or FM radio broadcasts in favor of only digital.

We're still quite early in the transition to digital radio broadcasting in the traditional AM and FM radio bands. The majority of new radios (cars, portables, tabletops, stereos, etc.) don't even come with digital (HD Radio) reception built in. In contrast, note that a requirement that new televisions have a built-in digital tuner has been a mandate for the past several years in preparation for the television conversion to digital only broadcasting. (Side note: HDTV and HDRadio, other than that they're both digital and use the letters "HD", have nothing in common. Changing one has nothing to do with changing the other.)

Further, not that the TV transition to digital is easy for everyone, but it least the addition of a converter box shouldn't be too difficult for the average TV owner. Can you imagine the chaos of either adding converters or replacing the existing car radios with digital units? "First crawl under your dash..."

Bottom line. While it's true that there are a number of options and efficiencies offered by converting to all digital broadcasting, it looks like it will be many years down the road before a conversion to "only digital" broadcasting can begin to occur.