Users of Marylandtoll facilities face what could be the most dramatic across-the-board increases in the state's history under a plan being developed by the Maryland Transportation Authority.

The proposed tolls are part of a four-year package of $210 million in increases that would put some of the fattest sacred cows in Maryland's transportation system on the chopping block — increasing Bay Bridgetolls, which have remained frozen since 1975, to $5 this year and $8 in 2013, and commuter rates that haven't been touched in 22 years.

Unlike the past several occasions on which the authority has raised tolls, the Bay Bridge would not be spared this time. The current toll, $2.50 on eastbound trips only, is less than the $2.80 charged for a round trip when the first span of the bridge opened in 1952. Under the plan released Thursday, the toll would jump to $5 this year and $8 in 2013. Commuter rates would increase to $1.50 in the first phase and $2.80 in the second.

The magnitude of the proposed increases comes as no surprise to political insiders and people who closely track Maryland's transportation system, but their scale is likely to be a rude jolt to state residents who would have to dig deeper into their pockets to use the Baltimore Harborcrossings, the Bay Bridge, the John F. KennedyMemorial Highway and other toll facilities.