HomeMy WebLinkAboutAgenda 06_BFJ Beta TIS Review 2022-02-14 MEMORANDUM
BUCKHURST FISH & JACQUEMART, INC. 115 FIFTH AVENUE NEW YORK, NY 10003 T. 212.353.7474 F. 212.353.7494
Date: February 14, 2022
To: Marla Keene, PE, Development Review Planner
Paul Conner, AICP, MCIP, Director of Planning & Zoning
From: Georges Jacquemart
Contact Information: T. 212.353.7477 F. 212.353.7494 E. G.Jacquemart@bfjplanning.com
Subject: Review of Traffic Impact Study for BETA Manufacturing Facility
The purpose of this memorandum is to summarize our review of the January 17, 2022 Traffic Impact Study (TIS) memorandum by VHB (David Saladino, P.E., and Karen Sentoff) for the proposed BETA Campus Master Plan in
South Burlington, VT. The following are our comments:
Base traffic volumes data:
The traffic impact analysis presented in the January 17, 2022 memo is based on traffic counts that were
performed in February 2021, May 2021 and January 2022. VHB adjusted these counts based on Pre-COVID data
from VTrans.
Traffic Generation
Table 2 shows the traffic generation by the 250 office employees incorrectly. Instead of the 77/16/18/73 vehicle
volumes (AM inbound/AM outbound/PM inbound/PM outbound), the correct numbers should be
142/19/25/120. The subtotal traffic generation volumes are correct.
Note that for the 285,000 SF manufacturing building VHB chose to estimate the traffic generation based on the
250 office employees plus the generation of 255 manufacturing employees. This yielded a total of 252 vehicle
trips in the AM peak hour and 229 vehicle trips in the PM peak hour. If the manufacturing building were considered
as one 285,000 SF manufacturing building and the traffic generation was based on gross floor area, the traffic
generation volumes would be 194 in the AM peak hour and 203 in the PM peak hour.
In regards to the retail uses projected for Commercial Building 3 VHB uses the ITE land use code 820 even though
ITE in its 11tth Edition of the Trip Generation Manual indicates that category 820 applies to uses with floor areas
that are larger than 150,000 SF. For uses that are smaller than 40,000 SF ITE recommends using land use
category 822. The use of category 822 would yield 45 vehicles trips in the AM peak hour and 124 vehicles trips
in the PM peak hour, compared to VHB’s estimation of 145 vehicles trip in the AM peak hour and 170 in the PM
peak hour.
BFJ concludes that the traffic generation of 499 vehicle trips in the AM peak hour and 513 vehicle trips in the PM
peak hour is probably too high given the reasons mentioned above and also because the peak hours of each use
will most likely not overlap. The manufacturing use is likely to have earlier peak hours compared to the other uses
on the campus.
MEMORANDUM
BUCKHURST FISH JACQUEMART, INC. 115 FIFTH AVENUE NEW YORK, NY 10003 T. 212.353.7474 F. 212.353.7494
BETA Review
February 14, 2022
Page 2
Synchro Analysis
For the delay and level of service calculations VHB assumes that the peak hour factors (PHF) will always be 1.00.
This is contrary to accepted practice. The peak-hour factor is introduced in these calculations to take into
consideration the fact that traffic flow varies within the peak hour and in effect calculates traffic conditions for the
worst 15-minute period within the peak hour. Using a peak-hour factor of 1.00 implies that traffic conditions will
be uniformly the same within the 60-minute period, when in fact there will be moments when conditions will be
worse and other moments when conditions will be better.
Conclusions
It is concluded that the traffic generation calculated in the VHB TIS is probably on the high side. However, this will
not affect the design of the new intersection proposed for Williston Road. Closing off Valley Road and building the
new intersection as proposed is a good approach to managing the traffic for this manufacturing campus.
The traffic generation of the proposed project is significantly below the traffic budget for this site in Zone 3 of the
Traffic Overlay District.
Please let us know if you have any questions.