other background traffic In the Charlestown area was assumed to grow In line 

 with forecasts developed by the Central Transportation Planning Staff (CTPS) as 

 part of the CANA Project analysis. Included In this background traffic are other 

 significant traffic generators, such as the USS Const Itut Ion . Currently, 25% of 

 the peop le who visit the USS Const I tut Ion a I so visit the Aquar I urn on the same day. 

 The same overlap Is assumed for 1994, when the USS Const Itut Ion and the Aquarium 

 will both be located In the Navy Yard. At this stage of analysis this approach Is 

 In line with the other conservative assumptions being made. 



In analyzing the traffic Impacts of the proposed Navy Yard development two 

 key Intersections were found to be the controlling points, as follows (see Figure 

 6): 



o The Intersection of Chelsea Street with the Gate 4 entrance; and 



o The City Square Intersection of Rutherford Avenue, Chelsea Street and 

 the 1-93 ramps (currently under construction as part of the Central 

 Artery North Area Project). 



Background volumes for the Chelsea Street/Gate 4 Intersection were assumed the same 

 as those forecast for the 1994, Navy Yard build-out condition with the addition of 

 the Tudor Wharf development. The City Square Intersection will be totally rebuilt 

 as part of the Central Artery North Area (CANA) Project. This rebuilt 

 Intersection, Including modifications proposed by the Boston Transportation 

 Department (BTD), was used as the basis for the analysis. 



Figure 5 shows the regional origins of Aquarium traffic, as well as MBTA 

 stops which might serve as potential shuttle locations. The figure shows that most 

 Aquarium traffic will originate from the south and will come through Boston. 

 Virtually all regional traffic, however, must travel through City Square under the 

 CANA project design. 



In analyzing City Square, background traffic levels for those vehicles 

 not travelling to or from Chelsea Street were the same as those used by the 

 Department of Public Works in their planning work for the CANA project. The 

 work completed for the CANA project also Included the assumption that 

 approximately 70% of the PM peak hour traffic travelling to and from the Navy 

 Yard would go t- rough City Square. 



18 



