Draft Project Impact Report - Boston Redevelopment Authority

Exeter Residences\888 Boylston
\\Mabos\projects\09916.00\docs\Permits\DPIR\Text\DPIR Chapter 4
Transportation081208-clean.docx
level-of-service designation is for the most critical movement which is most often the
left turn out of the side street. Table 4-1 shown below, presents level of service
criteria as set by the HCM.
Table 4-1
Level of Service Criteria
Level of Service
Transportation 4-14
Unsignalized
Intersection
Delay (sec/veh)
Signalized
Intersection
Delay (sec/veh)
A 0-10 0-10
B >10-15 >10-20
C >15-25 >20-35
D >25-35 >35-55
E >35-50 >55-80
F >50 >80
Source: Highway Capacity Manual (Transportation Research Board, 2000).
The analysis utilizes the evening peak hour as the worst case scenario for analyzing
network performance, since the study area performs better in the morning peak
hour. This is consistent with the findings of the FEIR for the Prudential Center and
the NPC/PNF.
Table 4-2 presents a summary of the results of the existing conditions analysis. It
should be noted that since the filing of the NPC/PNF, BTD had made several
changes to the signal timing and phasing sequence to the signalized intersections in
the Back Bay area. The traffic analyses presented in this DPIR were performed using
an adjusted SYNCHRO model which includes signal timing and phasing
adjustments as recently implemented by BTD for the entire Back Bay area. As
presented in the table below, all study area intersections operate at acceptable levels
of service (LOS D or better) under the existing condition during the weekday
morning, weekday evening and Saturday peak. Detailed Synchro reports are
included in the Technical Appendices.