Traffic
...
Transportation and Traffic Engineering
PLANNING. DESIGN
September 13. 1996
MrJ eff Kennedy
Twin County Credit Union
POBox 718
Olympia. WA 98507
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The
Trans~o
Group
TG 96290 00
SUBJECT'
TWIN COUNTY CREDIT UNION -TRIP GENERATION STUDY
Dear Jeff.
The purpose of this letter is to describe the trip generation characteristics of the proposed
Yelm Twin County Credit Union. This letter summarizes the results of a trip generation
analysis conducted at existing Twin County Credit Union facilities in the Thurston and Pierce
County area. The proposed Yelm Twin County Credit Union would be approximately 3.350
square feet (sf) and would serve approximately 890 members in its first year Since the trip
generation estimates will be used to assess traffic impact fees for the City ofYelm's 6 year
Transportation Improvement Program (TIP), growth in credit union membership was forecast
out over the 6 year horizon. The remainder of this memorandum describes the data collection.
analysis, and results of the trip generation study
ITE Trip Generation Manual
Generally. to estimate the traffic demand generated by a particular land use, traffic engineers
utilize the Institute of Transportation Engineers (ITE) Trip Generation ManuaL However, the ITE
Trip Generation Manual. 5th Edition does not have a specific land use category for a Credit
Union. The ITE Manual has a Walk-In Bank (Land Use 911), a Drive-In Bank (Land Use 912),
and a Walk-In, and Drive-In Savings and Loan (Land Uses 913 and 914) All four land uses have
limited data with the Drive-In Bank providing the most information however the data points are
scattered for a variety of independent variables thereby yielding inconsistent and unreliable
results.
The trip generation rates for a Drive-In Bank and a Drive-In Savings & Loan differ significantly
and widely across independent variables such as employees, number of drive-in windows, and
building square footage. It is important to recognize that there is only one documented study for
the Savings & Loan, and the trip rates for the Bank trip rate range from 3.0 to 242.5 trips per
1,000 gsf of building. Additionally, the trip generation to a Bank and/or a Savings & Loan is
affected by the surrounding land uses, traffic characteristics of surrounding roadways.
accessibility. services offered (Le Automated Teller Machines), etc. Since no reliable trip
generation data for a Credit Union was available, studies of existing Twin County Credit Union
facilities were undertaken to assess the trip generation characteristics of existing Twin County
Credit Unions.
Since both the Bank and Savings and Loan are significantly different than a Credit Union in that
membership is restricted at a Credit Union versus the open banking policies at a Bank and/or a
Savings and Loan, the trip generation study focused on traffic generated from a membership and
transaction basis. With restricted membership the Credit Union has fewer members to draw
upon than a Bank or a Savings & Loan. The independent variables in the ITE Trip Generation
Manual for Banks and Savings and Loans are building size. number of employees, and number of
drive-in windows. For a Credit Union, the membership at each branch is known and can be used
as a predictor of the total number of transactions. which in turn can be used to assess the travel
The TRANSPO Group, Inc. 14335 N E. 24th Street. SUite 201 Bellevue Washington 98007 FAX. 206/747 3688 206/641 3881
'-
The
Trans~o
Group
demand. The number of members is a more reliable variable for predicting traffic than any of the
previously mentioned ITE variables since it is the membership that actually generates the traffic.
Ms. Jeff Kennedy
September 13, 1996
Page 2
Data Collection and Analysis
To establish a more refined estimate of trip generation characteristics of the Twin County Credit
Union, transaction and traffic data were collected at existing Twin County Credit Union branch
facilities in Thurston and Pierce County that have similar characteristics to the proposed Yelm
branch. The traffic counts were conducted during the weekday PM peak hour on Wednesday
August 14, 1996. No traffic count information was taken at the Tacoma Branch since it is not a
self-contained branch like the Olympia and Lacey Branches. The attached worksheet shows the
results of the trip generation analysis for the three branches studied.
To arrive at a reasonable trip generation estimate, the total number of transactions during the
weekday PM peak hour was compared to the total number of members at each branch that you
provided. The total number of transactions per member during the weekday PM peak hour
ranged from 0 008 at Olympia and Tacoma to 0 019 at Lacey A comparison of the trip rates per
transaction yielded trip rates from 1 85 to 1 96 trips per transaction during the weekday PM peak
hour These trip rates are intuitive since generally one transaction would generate two auto trips
assuming all single occupant vehicles. The slightly less than 2.0 trip rate (1 85 to 1 96) reflect
the fact that not all visitors to the branch travel in single occupant vehicles. they may use
transit, walk, or be a passenger in another vehicle.
Since it is the Tacoma Branch that best replicates the membership base of that of the proposed
Yelm Branch, the weekday PM peak hour transactions/member rate of 0 008 was utilized.
Assuming a membership base of 890 for the Yelm Branch and a weekday PM peak hour
transactions/member rate of 0 008. a total of approximately 7 transactions is predicted to occur
at the Yelm Branch during the weekday PM peak hour in its first year of operation. Applying the
1 96 trips per transaction that was observed at the Olympia Branch to the proposed Yelm
Branch. a total of approximately 14 weekday PM peak hour trips are predicted for the proposed
Yelm Branch based on the data collected at the existing Twin County Credit Union Branches.
The City ofYelm estimates population and employment growth of approximately 4 percent per
year over the 6 year TIP horizon. Applying the 4 percent per year to the membership base of 890.
the total number of members in 6 years would be 1.126 Applying the transactions per member
rate of 0008 and 1 96 trips per transaction to the 1,126 total members yields a total of 17
weekday PM peak hour trips.
Trip Characteristics
Of the total number of trips to a facility such as a Bank. three basic types of trips typically occur
The three trip types are described below'
1 Pass-By Trips - These trips already exist on the roadways that provide primary
access to the development and are being made for some purpose other than visit-
ing the facilities (for example. work-to-home) Pass-by trips do not result in any
increase in background traffic volumes in the study area, and therefore have no
additional effect on the road system beyond the development's driveways.
2. Diverted Trips - This category refers to trips attracted from the traffic volume on
roadways within the vicinity of the generator but which require a diversion from
Ms. Jeff Kennedy
September 13, 1996
Page 3
The
TranSIIO
Group
that roadway to another roadway to gain access to the site These roadways could
include streets or freeways adjacent to the generator, but without access to the
generator Therefore. the diverted trip component of the total generated demand
typically causes no change in the total number of vehicle trips within the overall
road system of the area. This shift in traffic patterns through diversion often
causes a net reduction in total vehicle miles traveled on the areawide transporta-
tion system.
3. New (Primary) Trips - These trips are those that would not have been made with-
out the existence of the proposed development. Therefore, this is the only trip type
that results in an increase in the total number of trips made within the study area.
These are also the only trips that represent additional vehicle miles of travel on the
transportation system.
For the purposes of the analysis for the proposed Yelm Twin County Credit Union, the pass-by
trip components were assumed to be 30 percent of the total trips. Although there is no specific
information in the ITE Trip Generation Manual for trip characteristics of financial institutions, a
trip to a Credit Union is typically part of another trip to and from a separate origin and
destination. It is important to recognize that the maj ority of members at the proposed Yelm
Branch are already being served by the existing Olympia and Lacy Branches. Thus, these Yelm
Branch members who are utilizing existing Olympia and Lacey Branches would already be on
the roadway as either a pass-by or diverted trip to the new Yelm Branch. Table 1 shows the
estimated trip generation for the proposed Yelm Branch of the Twin County Credit Union.
Trip Generation
PM Peak Hour
17
5
12
As shown in Table 1, the proposed project is expected to generate a total of 17 weekday PM peak
hour trips after 6 years of growth, with 12 of these being net new trips to the street system. We
trust that this analysis provides the level of detail necessary for accurately estimating the trip
generation from your proposed Yelm Branch. Please call me if you have any questions or
comments regarding the analysis described in this letter
Sincerely,
The TRANSPO Group. Inc.
-T6~ y; Uec{jy~r
i
Bruce R. Haldors
Senior Transportation Engineer
Attachment
\96290\96290L 1
Twin County Credit Union
Trip Generation Analysis
Lacey - 1135 Bowker St
TIME END IN OUT
4:15 17 23
4:30 22 21
4 45 15 20
5:00 22 23
5.15 15 25
5:30 14 18
5.45 2 8
6:00 2 2
No. of Members =
Transactions/Member =
4,695
0.019
TOTAL
40
43
35
45
40
32
10
4
HOURLY TRANS. TriplTrans.
163
163
152
127
86
88
1 85
Olympia - 1020 E. 5th
TIME END IN OUT
4'15 12 13
4~0 10 14
4.45 18 13
5:00 18 17
~15 20 16
5~0 10 19
5.45
6:00
No. of Members =
Transactions/Member =
8,550
0008
TOTAL
25
24
31
35
36
29
Tacoma Branch
No. of Members = 1,383
Transactions (4 PM - 5 PM) = 11
Transactions/Member = 0.008
TRIPGEN.XLS
HOURLY TRANS TriplTrans.
115
126
131
67
1.96
The
Transllo
Group
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Transportation and Traffic Englneenng
PLANNING-OESIGN
The
TranSIIO
Group
August 19. 1996
TG 96290 00
Mr Jeff Kennedy
1\vin County Credit Union
POBox 718
Olympia, WA 98507
SUBJECT:
TWIN COUNTY CREDIT UNION -TRIP GENERATION STUDY
Dear Jeff.
The purpose of this letter is to describe the trip generation characteristics of the proposed
Yelm 1\vin County Credit Union. This letter describes the results of a trip generation analysis
conducted at existing 1\vin County Credit Union facilities in the Thurston and Pierce County
area. The proposed Yelm 1\vin County Credit Union would be approximately 3.350 square feet
(sO and would serve approximately 890 members. The remainder of this memorandum
describes the data collection. analysis, and results of the trip generation study
ITE Trip Generation Manual
Generally. to estimate the traffic demand generated by a particular land use. traffic engineers
utilize the Institute of Transportation Engineers (ITE) Trip Generation Manual. However, the ITE
Trip Generation Manual. 5th Edition does not have a specific land use category for a Credit Union.
The ITE Manual has a Walk-In Bank (Land Use 911), a Drive-In Bank (Land Use 912). and a
Walk-In, and Drive-In Savings and Loan (Land Uses 913 and 914) All four land uses have
limited data with the Drive-In Bank providing the most information however the data points are
scattered for a variety of independent variables thereby yielding inconsistent and unreliable
results.
The trip generation rates for a Drive-In Bank and a Drive-In Savings & Loan differ significantly
and widely across independent variables such as employees. number of drive-in windows, and
building square footage. It is important to recognize that there is only one documented study for
the Savings & Loan, and the trip rates for the Bank trip rate range from 3 0 to 242 5 trips per
1,000 gsf of building. Additionally, the trip generation to a Bank and/ or a Savings & Loan is
affected by the surrounding land uses. traffic characteristics of surrounding roadways.
accessibility. services offered (Le. Automated Teller Machines). etc. Since no reliable trip
generation data for a Credit Union was available, studies of existing 1\vin County Credit Union
facilities were undertaken to assess the trip generation characteristics of existing 1\vin County
Credit Unions.
Since both the Bank and Savings and Loan are significantly different than a Credit Union in that
membership is restricted at a Credit Union versus the open banking policies at a Bank and/or a
Savings and Loan, the trip generation study focused on traffic generated from a membership and
transaction basis With restricted membership the Credit Union has fewer members to draw
upon than a Bank or a Savings & Loan. The independent variables in the ITE Trip Generation
Manual for Banks and Savings and Loans are building size, number of employees. and number of
drive-in windows For a Credit Union, the membership at each branch is known and can be used
as a predictor of the total number of transactions. which in turn can be used to assess the travel
The TRANSPO Group Inc 14335 N E. 24th Street, SUite 201 Bellevue Washington 98007 FAX. 206/7473688 206/6413881
Ms. Jeff Kennedy
August 19, 1996
Page 2
The
Tra nSII 0
Group
demand. The number of members is a more reliable variable for predicting traffic than any of the
previously mentioned ITE variables since it is the membership that actually generates the traffic
Data Collection and Analysis
To establish a more refined estimate of trip generation characteristics of the Twin County Credit
Union, transaction and traffic data were collected at existing Twin County Credit Union branch
facilities in Thurston and Pierce County that have similar characteristics to the proposed Yelm
branch. The traffic counts were conducted during the weekday PM peak hour on Wednesday
August 14, 1996. No traffic count information was taken at the Tacoma Branch since it is not a
self-contained branch like the Olympia and Lacey Branches. The attached worksheet shows the
results of the trip generation analysis for the three branches studied.
To arrive at a reasonable trip generation estimate. the total number of transactions during the
weekday PM peak hour was compared to the total number of members at each branch that you
provided. The total number of transactions per member during the weekday PM peak hour
ranged from 0008 at Olympia and Tacoma to 0 019 at Lacey A comparison of the trip rates per
transaction yielded trip rates from 1 85 to 1 96 trips per transaction during the weekday PM peak
hour These trip rates are intuitive since generally one transaction would generate two auto trips
assuming all single occupant vehicles. The slightly less than 2 0 trip rate (1 85 to 1 96) reflect
the fact that not all visitors to the branch travel in single occupant vehicles. they may use transit,
walk, or be a passenger in another vehicle.
Since it is the Tacoma Branch that best replicates the membership base of that of the proposed
Yelm Branch. the weekday PM peak hour transactions/member rate of 0008 was utilized
Assuming a membership base of 890 for the Yelm Branch and a weekday PM peak hour
transactions/member rate of 0008. a total of approximately 7 transactions is predicted to occur
at the Yelm Branch during the weekday PM peak hour Applying the 1 96 trips per transaction
that was observed at the Olympia Branch to the proposed Yelm Branch. a total of approximately
14 weekday PM peak hour trips are predicted for the proposed Yelm Branch based on the data
collected at the existing 1\vin County Credit Union Branches.
Trip Characteristics
Of the total number of trips to a facility such as a Bank. three basic types of trips typically occur
The three trip types are described below'
1 Pass-By Trips - These trips already exist on the roadways that provide primary
access to the development and are being made for some purpose other than visit-
ing the facilities (for example, work-to-home) Pass-by trips do not result in any
increase in background traffic volumes in the study area. and therefore have no
additional effect on the road system beyond the development's driveways
2. Diverted Trips - This category refers to trips attracted from the traffic volume on
roadways within the vicinity of the generator but which require a diversion from
that roadway to another roadway to gain access to the site. These roadways could
include streets or freeways adjacent to the generator, but without access to the
Ms Jeff Kennedy
August 19, 1996
Page 3
The
Tra nSII 0
Group
generator Therefore. the diverted trip component of the total generated demand
typically causes no change in the total number of vehicle trips within the overall
road system of the area. This shift in traffic patterns through diversion often
causes a net reduction in total vehicle miles traveled on the areawide transporta-
tion system.
3 New (Primary) Trips - These trips are those that would not have been made with-
out the existence of the proposed development. Therefore. this is the only trip type
that results in an increase in the total number of trips made within the study area.
These are also the only trips that represent additional vehicle miles of travel on the
transportation system.
For the purposes of the analysis for the proposed Yelm Twin County Credit Union. the pass-by
trip components were assumed to 40 percent of the total trips. Although there is no specific
information in the ITE Trip Generation Manual for trip characteristics of financial institutions, a
trip to a Credit Union is typically part of another trip to and from a separate origin and
destination. It is important to recognize that the majority of members at the proposed Yelm
Branch are already being served by the existing Olympia and Lacy Branches. Thus, these Yelm
Branch members who are utilizing existing Olympia and Lacey Branches would already be on
the roadway as either a pass-by or diverted trip to the new Yelm Branch. Table 1 shows the
estimated trip generation for the proposed Yelm Branch of the Twin County Credit Union.
Table 1 Trip Generation Summary
Weekday PM Peak Hour
Trip Generation
Proposed Credit Union Trip %
Total Trips1 100%
Pass-By/Diverted Trips 40%
New Trips 60%
Source. Traffic CountslTransaction Data - August 1996.
PM Peak Hour
14
5
9
As shown in Table I, the proposed project is expected to generate a total of 14 weekday PM peak
hour trips, with 9 of these being net new trips to the street system. We trust that this analysis
provides the level of detail necessary for accurately estimating the trip generation from your
proposed Yelm Branch. Please call me if you have any questions or comments regarding the
analysis described in this letter
Sincerely.
The TRANSPO Group, Inc.
~R~aJ/f:!cftM-
Senior Transportation Engineer
Attachment
\96290\96290L 1
Twin County Credit Union
Tnp Generation Analysis
Lacey - 1135 Bowker St
TIME END IN OUT
4 15 17 23
4:30 22 21
4 45 15 20
5'00 22 23
5 15 15 25
5:30 14 18
545 2 8
6.00 2 2
No of Members =
Transactions/Member =
4,695
0019
TOTAL
40
43
35
45
40
32
10
4
HOURLY TRANS TripfTrans
163
163
152
127
86
1 85
88
Olympia - 1020 E. 5th
TIME END IN OUT
415 12 13
4:30 10 14
4 45 1 8 1 3
5:00 18 17
5 15 20 16
5:30 10 19
5.45
6'00
No of Members =
Transactions/Member =
8,550
0008
TOTAL
25
24
31
35
36
29
Tacoma Branch
No of Members = 1,383
Transactions (4 PM - 5 PM) = 11
Transactions/Member = 0 008
TRIPGEN.XLS
HOURLY TRANS TripfTrans
115
126
131
67
1 96
The
TranSIIO
Group
Dwin 6VlIJ1lJ2
CREDIT UNION
August 21,1996
here to help you get ahead financially
Catherine Carlson
City of Yelm
POBox 479
Yelm WA 95897
Re Proposed Twin County Credit Union Branch
Dear Ms Carlson,
Enclosed is a traffic scoping letter and independent trip analysis performed for us
by Bruce Haldors, of the Transpo Group Any questions that you may have
regarding the data provided can be directed to Mr Haldors at (206) 641-3881
He will be on vacation from August 22 through August 29, but can be reached
either before or after those times
I believe this is the only additional information you had requested in reviewing
our site plan application for construction of a new branch at 1105 Yelm Avenue
If you need any further information, please contact me at 357-9917, extension
402
(Siric;),.,eIY' ~!/
, / tu1 fLU/~
eff ',n e y
Vice lesident Branc~ Administration
TWIN COUNTY CRE1 IT UNION
/
oW OLYMPIA/ADMIN.-
2400 Evergreen Pk. Dr. SW
Olympia, WA 98502
(360) 357-9911
FAX (360) 754-0646
o OLYMPIA 0
1020 E. Fifth
Olvmpia, WA 98501
(360) 357-9911
FAX (360) 943-6105
- LACEY.-
- ABERDEEN 0
o CENTRALlA -
1320 South Gold
Centralia, WA 98531
1-800-235-8946
FAX (360) 736-3370
o TACOMA.
8904 5. Tacoma Way, Suite 1
Tacoma, WA 98499
(206) 581-9211
FAX (206)588-7028
1135 Bowker 51. 5E 401 E. Market
Lacey, WA 98503 Aberdeen, WA 98520
(360) 357-9911 1-800-235-8946
FAX (360) 459-7896 FAX (360) 533-6707
Mail To' PO Box 718 · Olympia, WA 98507-0718