When it comes to progress, nothing says it better than paved roads. But in these economic times, paved roads are too costly. In Michigan, 20 of its 83 counties have turned rural roads back to gravel. While the practice is most common in Michigan, the sour economy and high price of pavement has also driven municipalities in Pennsylvania, Indiana and Vermont to roll up the asphalt -- the price of which has more than doubled over the past three years to about $400 a ton. Cash-strapped towns can't afford to repave roads let alone fix potholes. That's particularly true in cold-weather states, where roads take a beating from freeze-and-thaw cycles and road salt. In Michigan, 50 miles of paved road has been converted to gravel in the past few years -- most are lightly traveled back roads but at least one county in Michigan turned a 10-mile stretch of primary road into gravel. Montcalm County claims it saved $900,000 converting the pothole-plagued road. The conversion might save money up front and may even make sense for low-traffic roads, but a 2005 study by the Minnesota Department of Transportation found that high-traffic gravel roads can cost more per mile over a several year period than paved roads.