Elements of the existing bicycle network or "bikeways" include bikepaths parallelling water routes, rail-trails, on-road bike space, and little-used back streets and roads. A simple way to connect existing and proposed bikeways is to form loops, a concept familiar to any recreational cyclist. The advantage of a loop is that you can start anywhere on the loop and reach any place or experience any section of the loop. Both the catchment area and the number of possible destinations are increased over any linear bikeway segment of the loop. Metropolitan and statewide networks, such as the one proposed in this paper, as well as regional facilities, such as the East Coast Greenway, can be built up from bikeway loops.
The Paul Dudley White Charles River Bikepath provides 14 miles of relatively car-free travel along both sides of the Charles River, connecting Newton, Watertown, and Cambridge to downtown Boston. While the most heavily used section, Frederick Law Olmsted's Charles River Esplanade, is 100 years old, completion of the loop by extending it upstream to Watertown from the BU Bridge, on the south side of the river, and Harvard Square, on the north, was only completed in the early 1980's. The Metropolitan District Commission (MDC) was funded by the federal Environmental Protection Agency specifically to build a prototypical urban bicycle transportation loop.
In 1987, the Southwest Corridor Linear Park was built in conjunction with the Massachusetts Bay Transportation Authority's (MBTA) Orange Line Rapid Transit replacement project. A substitute for the proposed extension of Interstate 95 through the neighborhoods of Boston, this is a model multimodal transportation corridor which still includes four lanes of street traffic, two rapid transit tracks, two rail lines, and separate bicycle and pedestrian paths.
The 10-mile-long Boston Inner Loop completes the Emerald Necklace. Following the Muddy River upstream through the Back Bay Fens, Brookline, and the ponds of Jamaica Plain, it follows back streets and a piece of the Arnold Arboretum to reach Forest Hills. The Southwest Corridor Linear Park takes the route directly toward downtown Boston, where six blocks of Dartmouth St. and a ramped foot bridge connect the route to the river The Charles River Esplanade completes the loop back to the Muddy River and the Emerald Necklace. Each of the segments of this 10-mile loop provides a useful commuting route as well as access to urban open space.
The Two Rivers Loop extends the Charles River Bikepath upstream through Watertown, Newton, Needham, and West Roxbury to Dedham, where a greenway could follow the Mother Brook, into which one-fourth of the flow of the Charles River has been diverted since the 1600's, to the Neponset River in Hyde Park. The return to the Charles River can then be made on the Boston Outer Loop, either over the hilly portion of Boston and down the Muddy River or down the Neponset River and back along Boston Harbor.
A Somerville-Cambridge Loop could run from the north side of the Charles River Bikepath to the MBTA Alewife Station via a route being researched by Cathy Lewis of the Central Transportation Planning Staff. It would follow Alewife Brook to the Mystic River and the existing MDC Mystic River Bikepath, with some significant gaps filled, could be extended to the Charlestown waterfront. The loop would close in the extension of the Charles River bikepath under proposed new Central Artery River Crossing overpasses.
A North Shore Inner Loop can leave the Mystic River in Malden to follow the proposed Bike to the Sea bikepath through Everett and Revere to the sea. A brief ride on streets connects to the proposed Great Marsh Park, which follows an abandoned railroad corridor south across East Boston to the harbor. A waterfront, or near-waterfront, route upstream along the Mystic River closes the loop. Northern extensions of this loop could be made on unused railroad right-of-way and rural roads all the way to Newbury.
The Northwest Suburban Loop runs from Alewife Station out the Minuteman Bikeway to Bedford and along the same right-of-way to West Concord, where it connects with the proposed north-south Lowell-Sudbury trail. Proceeding south on that trail, we connect to the proposed Central Massachusetts trail from Sudbury back to Waltham. Alternate routes would be to follow the Assabet River via back roads and a proposed rail trail to Hudson or to connect to the Route 126 bikepath to Wayland. All three of these routes connect to the proposed Central Massachusetts Railroad rail trail, which runs from Hudson (or points west) east to Waltham. The proposed Charles River Bikepath extension is only a few blocks away from the rail trail near Waltham center and carries us downstream to the Charles River-Alewife connector to complete the loop
The Bay Circuit is a potential greenway connecting many parcels of undeveloped public and private land in an arc from Ipswich and Newbury on the North Shore to Duxbury on the South Shore. Conceptualized by Charles Eliot in the 1920's, it is becoming reality under the stewardship of the Bay Circuit Alliance. While portions of this route will only be open to foot traffic, much of it will be usable by bicycles.
A turn west instead of east on the Central Mass. rail trail creates the still larger Massachusetts/Rhode Island Loop, on a route currently under consideration for inclusion in the East Coast Greenway. Following the Central Mass. to the Wachusett Reservoir, it turns south on the paved shoulders of Massachusetts Route 70 and the parkways along Lake Quinsagamond through Worcester to the Blackstone River Greenway which goes all the way to Providence, Rhode Island. A return to Boston can be made along an abandoned railroad right-of-way from Seeconk on the Massachusetts border all the way to Norwood, where an extension of the Neponset River Greenway could lead to Boston where either branch of the Boston Outer Loop returns to the Charles River and Alewife Station.
Tom Pendleton of the East Coast Greenway Alliance has suggested a still larger Southern New England Loop which uses the Central Mass. right-of-way all the way to Amherst (with a detour around Quabbin Reservoir), where it becomes the Five College bikepath to Northampton. After following the proposed Connecticut River Greenway south to Hartford, rail trails can be followed all the way to Providence. Either branch of the Mass./Rhode Island Loop can be taken to close the larger loop.