HomeMy WebLinkAboutSP-22-032 - Supplemental - 0119 Tilley Drive (49)
BUCKHURST FISH JACQUEMART, INC. 115 FIFTH AVENUE NEW YORK, NY 10003 T. 212.353.7474 F. 212.353.7494
MEMORANDUM
To: Marla Keene, PE
City of South Burlington Development Review Planner
From: Georges Jacquemart, PE, AICP, Principal
Mark Freker, Senior Planner
Subject: Review of Traffic Impact Assessment for 119 Tilley Drive
Date: September 1, 2022
Introduction
This memo provides findings from BFJ’s review of the May 27, 2022 Traffic Impact Study (TIS) for the proposed
UVM Medical Center Outpatient Surgery Center at 119 Tilley Dr. prepared by Wall Consultant Group (WCG).
Trip Generation Estimates
For the proposed 84,006 sf Outpatient Surgery Center, WCG developed a site-specific trip generation
estimate rather than using ITE ratios for land use categories such as Hospital, Clinic, and Medical/Dental
Office. BFJ concurs with WCG’s conclusion that the ITE uses are not comparable enough to the trip
generation of the proposed Outpatient Surgery Center.
WCG’s custom trip generation is based on staffing models provided by UVM MC and the 24-Hour staff/
patient arrival and departure estimations. WCG assumes a total of 215 employees, 12 operating rooms,
and an estimated 112 patients per day. Note that the surgical center would effectively operate from 5:50
AM when the first shift of professional staff arrive to 7:30 PM when final professional staff leave. WCG
presents the following vehicle trip generation for the Outpatient surgery center:
AM Peak Hour: 126 trips
PM Peak Hour: 129 trips
BFJ agrees with this methodology and finds the peak-hour traffic generation estimates to be reasonable.
Internal Capture Assumptions
WCG states that some of the traffic generated by the outpatient surgery center will remain internal
between the surgery center and the near-by Red Barn Market & Deli, the argument being that the trips
made between the two sites regardless of travel mode will not travel along Tilley Drive and are
considered internally captured. We disagree with this assumption, since the deli is an existing use with
its existing traffic generation. Today’s trips to or from the deli are not likely to divert to the surgery
center and any trips to or from the surgery center that stop over at the deli would constitute additional
trips to the deli. If we had the reverse situation where the surgery center existed and the deli was added
the internal capture would be more real. Some of the future staff and doctors, and possibly some
visitors/patients may walk to the deli to purchase coffee, snacks or lunch, however, these trips would be
limited in their numbers and would mostly occur during non-peak hours. We recommend that the
BUCKHURST FISH JACQUEMART, INC. 115 FIFTH AVENUE NEW YORK, NY 10003 T. 212.353.7474 F. 212.353.7494
applicant should not take any credit for internal capture. By the way if the applicant were to take credit
for internal capture the numbers of credited trips have to be the same inbound and outbound.
TDM Trip Reduction Credit
Trip generation reductions have been applied to the analysis based on VTrans TDM guidelines. BFJ
reviewed these guidelines and raises the following concerns:
WCG assigns a 3% credit in relation to parking supply management. We do not see how a
reduced parking supply may be reasonable in this case and question the validity of this credit.
Any shared parking with the nearby deli would not reduce traffic generation.
A 9% credit was assigned in relation to joining a TMA (small site, >100 workers). TMA services
include ridematching, vanpool support, guaranteed ride home, financial incentive/rewards
programs, transit subsidies/discounts. We do not believe that this credit to be assigned to the
patients visiting the clinic nor to the doctors who are not on a regular schedule and come for a
few hours on a particular day. We recommend that this credit be reduced to 5% and that the
TMA membership becomes condition of the approval.