25A-139 Bates St_Montessori Traffic Memo_Addendum_2016
ProTerra Design Group, LLC Ph:(413)320‐4918
4 Bay Road, Building A, Suite 200
Hadley, MA 01035 E: info@proterra‐design.com
ADDENDUM A
Traffic Impact Statement for a Proposed Two‐Story Upper Elementary
& Middle School Building, The Montessori School of Northampton
EXECUTIVE SUMMARY
City of Northampton staff requested that traffic impacts be analyzed for trips generated from both the
upper and lower levels of the proposed school building. The purpose of this Addendum A is to
document our opinion of the anticipated results of traffic impacts for the existing school and proposed
two‐story elementary and middle school building in Northampton, Massachusetts in the event of a full
build‐out of the upper and lower classroom levels.
Traffic conditions evaluated for this Addendum A:
Existing plus new school full build‐out traffic conditions (Full Build‐out 7,400 SF)
Level of service (LOS) analyses were conducted for the turning movements into and out of the existing
parking lot driveway associated with the existing school building along Bates Street. Site trips generated
by the two‐story school building at full build‐out were added to the roadway network to determine
impacts.
FULL BUILD‐OUT TRIP GENERATION AND DISTRIBUTION
Based on the City of Northampton City Code, Chapter 350 – Zoning, §350‐11.6, peak‐hour trip
generation for schools equals 10 trips per 1,000 square feet of building area. The full build‐out scenario
assumes that the lower level of the proposed school building will be finished out into classrooms with
additional students. The proposed school trip generation was divided for entering and exiting trips
before combining traffic volumes with the existing traffic count volumes. The data summarizing the
expected number of peak‐hour trips is outlined in Table A1.
TABLE A1: TRIP GENERATION
LAND USE SIZE TRIP GENERATION
RATE
PEAK
TRIPS
ENTERING
PEAK
TRIPS
EXITING
PEAK
TRIPS
PROPOSED
SCHOOL
(UPPER LEVEL)
Schools 3,700 SF 10 / 1,000 SF 37 22
(60%)
15
(40%)
PROPOSED
SCHOOL
(LOWER LEVEL)
Schools 3,700 SF 10 / 1,000 SF 37 22
(60%)
15
(40%)
TOTAL 74 44 30
ProTerra Design Group, LLC Ph:(413)320‐4918
4 Bay Road, Building A, Suite 200
Hadley, MA 01035 E: info@proterra‐design.com
The existing plus new school full build‐out (Full Build‐out 7,400 SF) peak‐hour turning movement
volumes are illustrated in Figure A1. A 60% / 40% split of entering and exiting trips, respectively, was
utilized for analysis. It was assumed that future trips to and from the existing school parking lot will be
proportionally split along Bates Street similar to existing conditions. As a worst case analysis, new trips
were analyzed mimicking the existing traffic patterns by performing left or right turns from the school
parking lot.
FULL BUILD‐OUT TURNING MOVEMENT ANALYSIS
Turning movement operational condition analyses for the exiting plus new school full build‐out (Full
Build‐out 7,400 SF) scenario were performed at the intersection of Bates Street and the existing school
parking lot entrance. Analyses were conducted using Highway Capacity Manual 2000 methodologies for
unsignalized intersections. For simplicity, the average control delay is equated to a grade or Level of
Service (LOS) based on the threshold of driver accepted delay. The amount of delay is assigned a letter
grade A through F, LOS A representing little or no delay and LOS F representing very high delay.
Results of the existing plus new school full build‐out (Full Build‐out 7,400 SF) peak hour analyses are
summarized in Table A2.
TABLE A2: INTERSECTION LEVEL OF SERVICE
(AM PEAK HOUR)
LOCATION FULL BUILD‐OUT
(7,400 SF) EXISTING
EXISTING +
NEW SCHOOL
(3,700 SF)
Bates Street & Existing School Parking Lot
Entrance/Wright Builders, Inc. Entrance
DELAY
(sec/veh) LOS DELAY &
LOS
DELAY &
LOS
WB Left & Right 10.7 B 10.1
B
10.3
B
EB Left & Right 8.9 A 8.7
A
8.8
A
NB Left 7.3 A 7.3
A
7.3
A
SB Left 7.9 A 7.7
A
7.8
A
CONCLUSION & RECOMMENDATIONS
Based on the results of all the capacity analyses and expected traffic patterns, in our opinion, the
proposed two‐story elementary and middle school building at full build‐out will not have adverse
impacts to the surrounding roadway system. Provided traffic management recommendations are
applied and maintained, the Level of Service will not decrease along Bates Street due to the minimal
ProTerra Design Group, LLC Ph:(413)320‐4918
4 Bay Road, Building A, Suite 200
Hadley, MA 01035 E: info@proterra‐design.com
addition of traffic from the proposed expansion of the Montessori School of Northampton. Existing
parking, as described within the “Traffic Impact Statement,” will meet the City of Northampton Zoning
Code parking requirements for the full build‐out of the proposed school.
Previous recommendations outlined within the “Traffic Impact Statement” for the proposed upper
elementary and middle school remain valid based on the full build‐out scenario analyses.