Gov. O'Malley will announce the construction of a new Dover Bridge across the Choptank River. (Kim Hairston and Michael Dresser/Baltimore Sun video)

Residents of the Middle Eastern Shore have learned through decades of hard experience that they can't trust the Dover Bridge.

The decrepit relic of the Herbert Hoover years, which crosses the Choptank River between Talbot and Caroline counties, is designed to swing open like a gate to let boat traffic pass. But when it gets stuck in the open position, as residents say it often does, drivers can be forced to wait in miles-long lines or embark on a detour that can add 30 to 45 minutes to what is normally a 10-minute trip.

"In its day it was a nice bridge, but I think its day is done," said Tim Jester, who operates a farm stand on the Caroline side of the bridge.

Gov. Martin O'Malley agrees. The governor will visit the bridge today to announce — at long last — that the state plans to begin construction of a $50 million replacement span next summer.

The new bridge, expected to take three years to build, will rise 48 feet above the Choptank so it won't have to open to let boats pass. Unlike the current bridge, it will have shoulders where vehicles can pull off in an emergency. Plans call for the old bridge to be kept permanently in the open position for use as a fishing pier.

Among those planning to attend the announcement today is George Jackson of American Corner in Caroline County, who's been pushing the state to replace the bridge since the 1990s. Jackson, 65, has seen two previous governors announce plans for a new span, but this time he's hopeful it will really happen.

"It's been a long struggle — it has — and no governor's gone this far before," he said. "You've got a happy old fat man sitting here."

The governor's announcement is part of a road show he's taking around the state to show Marylanders the projects his administration is undertaking with the revenue gained by passing the unpopular gas tax increase he proposed during this year's General Assembly session. The Dover Bridge event will highlight several long-desired projects on the Eastern Shore, where resistance to the gas tax measure was especially fierce.

Among the projects he will announce are a $52 million new interchange at U.S. 301 and Route 304 in Centreville, a top safety priority in Queen Anne's County, and $42 million for the next stage of the widening of Route 404 — the road to the Delaware beaches.

On the Shore, replacing the Dover Bridge is an especially big deal — economically, politically and symbolically.

"Unless you live on the Eastern Shore and unless you understand the geography and the travel patterns of the mid-Shore, it's impossible to understand just how meaningful this bridge really is," said Len Foxwell, deputy to Comptroller Peter Franchot and a Dorchester County native who has been following the bridge fight for two decades. "This is not just a matter of congestion relief or transportation mobility. It is quite literally a matter of life and death for the families of the mid-Shore."

A Maryland map shows why. The Dover Bridge on Route 331 is the only crossing of the Choptank between Denton and Cambridge. If the 81-year-old, swing-span bridge is stuck open, motorists from parts of Caroline and Dorchester must drive an extra 20 to 30 miles to get to Easton by a roundabout route.

"It's our intercounty connector; it's our way to get to the hospital," Larry C. Porter, a Republican on the Caroline County Commission.

Porter said the bridge also is dangerously narrow.

"It might be structurally sound, but it's functionally obsolete," he said. "If you get two tractor-trailers passing at the same time, they hit mirrors."

Capt. Troy Plutschak of the Preston Volunteer Fire Department in Caroline said that when the bridge is out of service, it can turn a 10- to 15-minute emergency trip to the hospital in Easton to a 20- to 30-minute ride to medical centers in Cambridge or Seaford, Del. He said he's not aware of any lives lost as a result, but the worry is always there.

"It could very well hurt the citizens," he said.

While state engineers insist the bridge is safe to drive on, its appearance doesn't inspire confidence. During a tour of the bridge's underside Thursday, Jackson reached out to a rusty ledge and pulled out a flaked-off piece of rusty steel the size of a dagger blade.

"That's a piece of the Dover Bridge," he said.

In other places, deep cracks show in the concrete base, and structural steel has pulled away from the roadway.