IV. TRAFFIC ANALYSIS FINDINGS 



Traffic analysis Is conducted using the concept of level of service. Level of 

 service at signalized Intersections is measured In seconds of delay and defined as 

 "average stopped delay per vehicle". This delay Is a measure of driver discomfort 

 and lost time. Level of service 'B', for example, means that a driver waiting at 

 an Intersection will experience an average delay of between five and fifteen 

 seconds before going through the Intersection. Level of service 'A' describes 

 traffic flow with the shortest delays, ranging to level of service 'F' with the 

 longest delays. The specific delays associated with each level of service are 

 shown In Table 6. 



In urban neighborhoods such as the Navy Yard area level of service 'D' Is 

 considered acceptable. Providing the required physical capacity to achieve level 

 of service 'A' or 'B' Is generally not economically or physically feasible in this 

 type of area. It should also be noted that the level of service represents the 

 average of all movements made in the Intersection. When the overall level of 

 service is 'D', It Is possible that some specific turns may experience level of 

 service 'E' or 'F' while others would be 'A', 'B' or 'C. 



TABLE 6 



LEVEL OF SERVICE CRITERIA FOR 

 SIGNALIZED INTERSECTIONS 



Level of Service 



A 

 B 

 C 

 

 E 

 F 



Tables 7 and 8 summarize the level of service for a summer peak season 

 weekday PM peak hour and Saturday peak hour for an assumed annual visitation level 

 of 2.1 million. For all levels It Is assumed that July/August visitation Increases 

 to 32.4% of the annual total, that 25% of Aquarium visitors travel by means other 

 than the automobile and that 45% of Navy Yard and Aquarium employees use public 

 transportation. It Is also assumed that parking would be either In the Navy Yard 

 or east of the Gate 4/Chelsea Street Intersection and that Gate 1 would not be 

 available for vehicular access to the Navy Yard. Level of service data are 

 provided for City Square, the Gate 4/Chelsea Street intersection and for a Gate 

 4/Cheisea Street/parking garage entrance Intersection. The latter intersection 

 would exist only If parking Is provided under Tobin Bridge or at the BHA Hayes 

 Square site. This would result In a new four way intersection at Gate 4 and 

 Chelsea Street. The left column In the table Indicates the level of service under 

 the current geometry of the Chelsea Street/Gate 4 Intersection. The right column 

 shows the level of service for a Gate 4/Cheisea Street Intersection which would be 

 Improved as described In the previous section. The tables show that with the 



22 



