HomeMy WebLinkAbout56655 Route 25 Southold Senior Condominium Traffic Impact AssessmentEngineering Associates,~.C.
66 Main Street
We,,thampton Beach, N.Y. 11978
63t-288-2480
631-288-2544 Fax
March 2g, 2006
Mr. Christopher M. Read
East End Development, LLC
666 Old Country Road
Garden City, New York 11530
Re;
Traffic Impact Assessment
Proposed Residential Development
56655 Main Road
Southold, NY
Dear Mr. Read:
As requested, Dunn Engineering Associates PC has completed our professional traffic engineering
evaluation in connection with the above project. The project envisions the construction of 24 semi-
attached residential condominium units for senior citizens, with associated amenities, and 3
affordable housing units. The senior condominium units will be contained in 8 separate buildings of
3 units each, and the 3 affordable housing units will be contained in a separate building. The 6.75
acre site is located on the north side of Main Road, NYS Route 25, m the hamlet of Southold,
Suffolk County, New York. The current site plan proposes a single access to Main Road. At present,
the site contains a single-family residence.
Figure I shows the location of the project site and Figure 2 shows the boundaries of the property and
the adjacent roadway network.
Our examination was performed to evaluate thc potential traffic impact of the proposed
development, including trip generation, access and safety. During the course of the study, the
following specific work tasks were performed:
Several personal visits to the site were made to attest to our observations of existing traffic
movements at various times of the day and under different conditions.
Data regarding traffic flow on Main Road was obtained and analyzed from the New York
State Department of Transportation.
Trip generation estimates were performed, utilizing information contained in the Institute of
Transportation Engineers report "Trip Generation", 7th Edition, the accepted industry
standard for applications of this nature.
F~GURE 1
LOCATION PLAN
SCALE: 1"=400'
FIGURE 2
SITE MAP
SCALE: 1
Mr. Christopher Read
March 28, 2006
Page 4
4. The proposed access arrangement was evaluated, from the standpoints of location and design.
The following sections present the results of our efforts in this regard.
Existing Conditions
Main Road, NYS Route 25, is a New York State highway facility that provides direct access to the
site. Although NYS Route 25 extends the entire length of Long Island, it serves as Main Street for
many of the communities along the north fork of Long Island. Near the site of the proposed
development, Main Road provides one lane in each direction, flanked by shoulders where parking is
permitted. The posted speed limit is 30 mph, but changes to 40 mph just east of the site. The site is
located on the eastern end of the commercial center of the hamlet of Southold, and development
along Main Road near the site is primarily commercial, although east of the site Main Road is
residential in nature. According to information provided by New York State Department of
Transportation, the Average Annual Daily Traffic (AADT) on Main Road in Southold in 2003 was
8453 vehicles per day. AADT is a transportation engineering and planning term defined as the
average traffic volume at a given location on any day of the year, including weekends.
NYSDOT has recently completed an improvement project on Main Road near the site. The project
included drainage improvements and resurfacing, but no capacity improvements. Therefore, Main
Road still provides one lane in each direction flanked by ten-foot shoulders.
Future Site Trip Generation
The current site plan for the proposed development envisions eight buildings containing 24
residential condominium units for seniors, and a ninth building providing 3 units of affordable
housing. Information contained in the report "Trip Generation", 7t~ Edition, published by the
Institute of Transportation Engineers, was utilized to estimate the number of new trips that can be
expected to be generated by thc proposed project. Land Use Code 252, Senior Adult Housing -
Attached, was utilized to estimate the number of new trips which can be expected to be generated by
the senior housing aspect of the development, and Land Use Code 230, Residential
Condominium/Townhouse was utilized for the three units of affordable housing. The results of this
analysis are presented in Table 1. As can be seen, during the weekday AM peak hour, the site will
generate 14 new trips, 5 entering and 9 exiting. Similarly, during the weekday PM peak hour, the
development will generate 10 new trips, 6 entering and 4 exiting. This is a relatively small amount
of new traffic, and it is not anticipated that this small number of new vehicles would have a
perceptible impact on traffic flow conditions on Main Road.
It should be noted that the number of trips shown in Table I was calculated based on the highest rate
of trip generation at any of the developments studied in the Trip Generation report. This was done
because the number of units in the proposed development is very small compared to those studied in
thc Trip Generation report, and in general, the developments with a smaller number of units tended
Mr. Christopher Read
March 28, 2006
Page 5
to have the higher rates of. trip generation per unit. It should also be noted that the existing single
family home on the site currently generates some traffic, but this existing traffic has been ignored for
purpose of this report. In this manner, the trip generation analysis provides a conservative estimate of
the amount of traffic expected to be generated by the proposed project.
Development
Enter :. "~: '=~,: ~e~
Senior Adult Housing - Attached
Land Use Code 252 4 5 3 3
24. Units
Residential Condominiums {Affordable
Units) 1 4 3 1
Land Use Code 230
3 Units
Total New Site Generated Traffic 5 9 6 4
Table 1
Site Generated Traffic
Access Examination
In keeping with good access management practices, the site plan for thc project proposes a single
driveway on Main Road. The driveway will serve both the senior housing and the affordable
housing. The site plan indicates that the driveway will be located at the westerly end o fthe property,
and will provide two lanes, one for entering traffic and one for exiting traffic. Left and fight tums
into and out of the site will be permitted at this access driveway. All parking areas provided on the
site can be accessed from the driveway.
Main Road has both vertical and horizontal curvature near the site. The crest of the vertical curve is
just east of the site. The site is also located on the inside of a horizontal curve. Sight distance
measurements were performed to ensure that adequate sight distance would be available at the
location of the proposed site access driveway to allow for safe operations. The 2001 edition of the
American Association of State Highway and Transportation Offteials (AASHTO) publication "A
Policy on Geometric Design of Highways and Streets" indicates that for design speeds of 35 mph,
390 feet of sight distance should be available for vehicles entering an intersection to safely do so. In
addition, for design speeds of 35 mph, AASHTO recommends that 250 feet of stopping sight
distance be available for drivers of vehicles traveling on the main mad to see a vehicle entering the
Mr. Christopher Read
Mamh 28, 2006
Page 6
road and stop safely, and .for design speeds of 45 mph, 360 feet of stopping sight distance be
provided. The 45 mph design speed was included because the speed limit on Main Road is 40 mph
just east of the site, so westbound vehicles on Main Road approaching the site might be traveling
slightly faster than eastbound vehicles, which would have a 30 mph speed limit. Sight distance
measurements performed at the location of the proposed driveway indicate that stopping sight
distance of 400 feet to the east and over 800 feet to the west is available. Therefore, adequate sight
distance is available for safe operation of the proposed driveway.
Conclusions
Based on the professional transportation engineering evaluation described above, it is concluded that
the proposed 27-unit residential development will result in a small number of new trips added to the
surrounding roadway network. The single access point to the proposed development is located to
provide adequate sight distance for vehicles to safely enter and exit the site from Main Road.
Therefore, the proposed 27-unit residential development will have minimal to imperceptible impact
on the safety and operation of the roadway facilities.
In light of the foregoing, and based on professional transportation engineering considerations, it is
recommended that the proposed project be approved.
If you have any questions or need any further information, please call me.
Sincerely,
Vincent Corrado
Senior Engineer / Senior Transportation Planner
VC:lam
L205336.Rev
P25115