Manchester NH Airport Access Rd under way
Traffic on the Everett Turnpike just south of Manchester is being rerouted to allow construction of an unusual 3-phase top-down bridge on the mainline to serve a short spur expressway to Manchester Airport. The underpass of the mainline of 2x2 lanes is part of a new trumpet interchange that will serve southbound Everett Turnpike traffic going to and from the airport. Support shafts are drilled, given their cages of rebar and poured with concrete and given caps. Prefabricated bulb-Tee concrete beams up to 55m (180ft) long make the two spans over the angled underpass, which is excavated and finished only after the Turnpike deck on top is restored. The work is done in three stages to keep traffic flowing on the Turnpike.
A bridge over the mainline would have put the spur road - called the Manchester Airport Access Road (MAAR) too high for the spur's first interchange with the lower US3 or Daniel Webster Highway, and would also have added to the cost of the bridge over the Merrimack River.
In the middle of the interchange is the established mainline Bedford Toll Plaza getting a couple of extra toll lanes to 8. (CORRECTION HERE - We first wrote it was being modernized.)
MAAR of 2x2 lanes is only 2.4km (1.5mi) in length but constitutes a connection off the busy north-south toll expressway directly into Manchester Airport. To date the airport has only been accessible by local roads.
Eagle nests and development or not
The plans for the MAAR have been fought over passionately for 20 years. A major issue was the impact of the river bridge on eagles that nest along the river.
Other issues have been the scale of new access provided for economic development with the ramps to US3 on the west bank and NH3A on the east bank. A thousand acres (405ha) of land for industry has been opened up for development by the ramps - the largest in southern New Hampshire - pitting developers and tax-base enhancing local officials against enviros and other anti-development elements.
The project was modified extensively to satisfy some complaints but seemed to languish in a Too Hard basket at NHDOT as arguments raged.
The project got full permitting - the federal Record of Decision - in April 2003 but even then it took four years for construction contracts to be awarded.
The design is tight with hardly any straight 2x2 lanes so close are the interchanges and bridges to one another.
There is a pair of braided ramps - an acute angled overpass - immediately east of the Turnpike allowing Turnpike NB to Airport traffic to avoid an awkward weave across Turnpike SB traffic to the NH3A - dealing neatly with a common problem of connecting two major parallel roads close to one another. Close diverge lanes require the tunnel under the Turnpike to be wider - effectively an extra lane - than otherwise.
Largest structure is a 367m (1205ft) bridge over the Merrimack River. Of six spans it is being built of steel plate girder it will have two piers in the river. The bridge has 2x3 lanes, one land each direction being to serve ramps, the other two to provide for continuous travel lanes.
There is considerable work rebuilding connecting roads in the vicinity especially US3.
After spanning NH3A the access road degenerates into a signalized arterial with three sets of signals, ending in the airport roads.
Old-fashioned stop-to-pay toll plaza kept in middle of project but no tolls on ramps
You have to wonder about the justification in 2007 of continuing with a new lane by lane stop-to-pay toll plaza - what with most toll authorities going for highway speed electronic tolling down the center, and several tollers moving to abandon cash collection altogether. The staffed Bedford toll plaza gets an access road with a bridge over the new Airport-to-Turnpike NB ramp.
The new ramps are without tolls, which means that opening of the interchange will cause the Turnpike to lose revenues. Traffic between Nashua and points south and the airport area using the new interchange will go toll free on the ramps, whereas before the interchange is built they have to go through the Bedford mainline plaza and pay a toll.
Total cost of the MAAR project is an estimated $123m and completion is scheduled for late 2010
TOLLROADSnews 2007-08-18 CORRECTION 2007-08-20