Maintaining Michigan's transportation network and expanding it where necessary to accommodate traffic growth between now and 2030 will cost about $81 billion, or $44 billion more than the revenue currently forecast to be available, a state long-range plan released yesterday states.

"Projected funding is not sufficient to sustain Michigan's transportation system, even at current levels of service," the report warns, adding that just to keep pace with expected inflation, an additional $6.33 billion needs to be raised during the Michigan Department of Transportation plan's time period.

But without additional funds, progress MDOT has made in recent years to replace failing bridges and repave battered roadways will regress, according to the report.