Resolution 2008-216
RESOLUTION NO. 2008- 216
A RESOLUTION OF THE BOARD OF COUNTY COMMISSIONERS OF
COLLIER COUNTY, FLORIDA, AMENDING THE COLLIER COUNTY
CONSOLIDATED IMPACT FEE ADMINISTRATIVE PROCEDURES
MANUAL BY REPLACING APPENDIX D WITH A NEW APPENDIX D,
ENTITLED "TRANSPORTATION IMPACT FEE ALTERNATIVE
IMPACT FEE STUDY GUIDELINES AND PROCEDURES" IN ORDER
TO ASSURE THAT ALTERNATIVE STUDIES ARE CONDUCTED IN AN
ACCURATE, FAIR AND EQUITABLE MANNER FOR THE APPLICANT
AND THE COUNTY AND PROVIDE FOR PAYMENT OF COSTS
ASSOCIATED WITH REVIEWING OR CONDUCTING THE
APPLICANT'S STUDY.
WHEREAS, on March 13,2001, the Board of County Commissioners adopted Ordinance
No. 2001-13, as amended, the Collier County Consolidated Impact Fee Ordinance, repealing and
superseding all of the County's then existing impact fee regulations, and consolidating all of the
County's impact fee regulations into that one Ordinance, codified in Chapter 74 of the Collier
County Code of Laws and Ordinances; and
WHEREAS, on July 31,2001, through Resolution No. 2001-292, the Board of County
Commissioners adopted the Administrative Procedures Manual for the Collier County
Consolidated Impact Fee Ordinance (the Manual) and authorized use of the guidelines and
procedures contained within the Manual by County staff and customers from the Collier County
development community; and
WHEREAS, Resolution No. 2001-292 directs County staff to regularly review the
Manual for necessary corrections and improvements and provides that future changes shall be
presented for adoption by resolution of the Board of County Commissioners; and
WHEREAS, County staff and the County's impact fee consultant have reviewed best
practices and procedures throughout the State of Florida and recommend revisions to the
guidelines and procedures relating to alternative impact fee studies to ensure an accurate rate is
assessed for the transportation impacts of a development and provide for payment of costs
associated with reviewing or conducting the applicant's study.
NOW, THEREFORE, BE IT RESOLVED BY THE BOARD OF COUNTY
COMMISSIONERS OF COLLIER COUNTY, FLORIDA, that:
I. Appendix D of the Administrative Procedures Manual for the Collier County
Consolidated Impact Fee Ordinance is hereby replaced by a new Appendix D, entitled,
Page I of2
'Transportation Impact Fee Alternative Impact Fee Study Guidelines and Procedures" as
shown in Exhibit A to this Resolution; and
2. In addition to the costs and fees required by Ordinance No. 2001-13, as amended, the
applicant is responsible to pay the costs associated with reviewing the applicants study or
conducting the study using the rates set forth in Appendix D-I, as shown in Exhibit B to
this Resolution.
THIS RESOLUTION ADOPTED after motion, second and majority vote favoring same,
this dd.cl day of ~ "'-\ J ' 2008.
A TTES'l':', .:.~
D~IGHTE:B.\~{l~K, CLERK
e-.~~~)k
~ AtteSt .~\ to, ~~~e~
/'I',W,'~tllf.t \' (! \ '
Ap roved as to form
an legal s fie' ency:
BOARD OF COUNTY COMMISSIONERS
COLLIER C TY, F ORillA
.
By:
TOM HENNING, CHAIRMA
Jeffr A. KI
Cou Alto Y
Page 2 of2
Appendix D
Transportation Impact Fee
Alternative Impact Fee Study Guidelines and Procedures
This appendix presents a proposed methodology for conducting an Alternative Fee Calculation
for transportation impact fees. An alternative impact fee calculation is required in instances
where the County and the developer are unable to reach an agreement for classification of a
proposed development to an equivalent land use category in the adopted fee schedule. When
conducting an alternative study, the applicant has the option to choose a consultant from the
County's General Planning Contract (GPC) list or use their own consultant with independent
oversight from one of the firms from the County's GPC list The cost associated with reviewing
the applicant's study or conducting the study shall be born by the applicant and shall be billed
using the rates included in the GPC contract, as amended. See Appendix D 1. Prior to the
adoption of the study, or issuance of a building permit or certificate of occupancy, all applicable
fees shall be paid. This appendix contains the requirements, procedures and methodology for
preparation, performance, and submission of an Alternative Fee Calculation Study.
1. Pre-application Meetinq. Before beginning the Alternative Fee
Calculation, the applicant or applicant's representative shall arrange and
attend a pre-application meeting jointly with the Impact Fee Coordinator
and the Transportation Services Division Administrator or designee to
discuss the requirements, procedures, and methodology of the
Alternative Fee Calculation. At the beginning of the pre-application
meeting, a determination by County staff shall be made as to whether the
proposed development exhibits unique characteristics that warrants
classification as a new land use category or if the development can be
categorized within an existing land use category and the resulting data
collected through the alternative fee calculation study shall result in
modification of data available for the respective land use category. An
application fee of $2,500 shall be due at the pre-application meeting. The
pre-application meeting shall normally cover the following topics:
a. Proposed Previous Studies
If the applicant proposes relying on the results of any previous studies
originally submitted as part of the zoning approval process, a copy of the
other report (s) shall be submitted. The County shall review previous
studies for sufficiency and applicability to the proposed new development
b. Credits
If an applicant proposes reducing the impact fee through use of a credit,
either for prior use of the property, right-of-way dedication, or road
improvement, this issue shall be reviewed at the pre-application
conference. If a Developer Contribution Agreement exists, the applicant
shall provide a copy of such agreement at the pre-application conference.
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c. Timeframe
The applicant shall have an option to conduct studies throughout the
year subject to the understanding that off season studies shall be
adjusted using FDOT peak season adjustment factors or another
adjustment factor as approved by the County.
d. New Land Use Rate Category
If the applicant believes that the land use categories included in the
County's fee schedule do not include an appropriate category for the
proposed development, the applicant shall provide an explanation and
supporting data/documentation to show how the proposed development
is different The discussion regarding the land use characteristics need
to occur during the pre-application meeting, prior to conducting the study.
However, if there is a disagreement between the applicant and the
County, the final approval for a new land use category shall be made
upon completion of the independent study based on the study results.
e. Proposed Study Sites
The applicant shall identify a minimum of three comparable sites to be
studied. The site description shall include the specific location, the
character of the location (Central Business District/downtown, urban,
suburban, or rural urbanized or rural areas), and the land use(s) at the
location (including ITE code and classification).
The applicant shall include an explanation of why the proposed sites are
similar to the proposed new development The explanation shall address
pertinent characteristics, such as land use, adjacent area, access to
roadway network, and demographics.
The applicant shall include a map showing the location of the proposed
new development and the proposed study sites.
County staff shall review the proposed study sites for applicability to the
proposed new development
For cases where three comparable sites are not available in Collier
County, please see Section 5 of this Appendix.
f. Study Data Elements
Study data elements shall include the impact fee formula demand
component variables. These are the trip generation rate, trip length and
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percent new trips factor. Each of these components is discussed below:
(1) Trip Generation Rate
The trip generation rate is normally determined by machine
counts. The applicant shall provide documentation depicting the
proposed machine counter sites and locations within the site.
County staff shall review the proposed sites for suitability of
equipment, hose/loop detector configurations, and the dates of
counting to reflect typical travel characteristics (i.e., excluding
holidays). The County staff shall specify the ievel of detail to be
included in the study report.
(2) Trip Lenqth and Percent New Trips
These two data items are normally determined by an
origin/destination survey, consisting of motorist interviews.
County staff shall review the proposed location of interviewers,
interview forms, dates and times of day for conducting interviews.
Documentation of the number of patrons that elected not to
participate is also required for evaluating the accuracy of data
collected.
The applicant shall identify any portions of trips to be excluded
from trip lengths, such as travel on the local, interstate, and/or toll
road systems. Trip length shall not be limited to County boundary
and shall be capped at 30 miles. If the applicant is using an
outside consultant, one week notification shall be required before
commencing origin/destination surveys and the applicant shall pay
for the County's GPC to be on-site for 2 days observing surveys.
(3) Other Data Items
County staff shall specify any other data items the applicant shall
be required to collect for the proposed study.
g. Proposed Data Collection Methodology
County staff shall review the applicant's proposed methodology for
analyzing the data collected in the study. This methodology shall follow
Section 3, Guidelines.
h. Report Format
The County staff shall discuss the required format for submitting the
study report. The applicant shall compile the study findings into a report
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structured as follows:
. Table of Contents
. Letter of Transmittal
. Findings of the Report
- Trip generation rate
- Trip length
- Percent new trips
. Impact Fee Calculations
. Appendices
- Trip generation rate summary
- Trip length worksheet
- Percent new trips worksheet
- Trip generation data (including original machine counts and
manual verification counts)
- Interview forms (use attached forms)
Subsequent to the pre-application meeting, the applicant shall submit
three copies of the proposed approach to the study to the Collier County
Office of Transportation Services. The County staff has thirty (30)
working days to respond in writing to the proposed approach. If County
Staff concur with the proposed approach, the applicant shall be notified to
proceed with the study. If County staff disagrees with the proposed
approach, County staff shall identify the problem areas for the applicant
The applicant shall receive approval from County staff before proceeding
with the study. In the event the applicant disagrees with a decision of the
County staff that effectively results in a denial of the alternative fee
calculation, the applicant may file a written appeal with the Board of
County Commissions following the procedures outlined in the Section 74-
204 (d) of the County's Code of Ordinances.
2. Methodoloqy. The Alternative Fee Calculation shall follow the prescribed
methodologies and formats in the Consolidated Impact Fee Ordinance.
The results of the Alternative Fee Calculation shall be submitted to both
the Impact Fee Coordinator and Transportation Services Division. The
following guidelines shall be followed when conducting an Alternative Fee
Calculation:
a. Seasonal Adjustment
Studies shall be conducted at a time which accurately reflects the
project's average annual impact. If a study cannot be completed at this
time, County staff shall determine the necessary seasonal adjustment
factor to be used to accurately reflect the proposed project's average
annual impact.
b. Collecting Trip Generation Data
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The applicant shall be required to place the machine counters at project
driveways, for a minimum of three consecutive weekdays of 24-hour
machine counting, on days representative of typical traffic patterns at that
site (not during a holiday, for example). The traffic counts shall occur
during the same days which the collection of trip length and percent new
trips data is conducted.
The data to be collected includes:
. Date and times of counts;
. A summary of counts by 15-minute increments (entering, exiting, and
total);
. Average daily volume; and
. Volume during the a.m. and p.m. peak hours of the adjacent street.
The applicant must verify the correct operation of the machine counters
by manually observing their proper data recording for at least two hours
during the a.m. or p.m. peak hour of the site (in fifteen minute
increments) during the same days that the machine count data is
collected. The machine counts shall then be reviewed to ensure that a
margin of error of 10 percent or less is achieved between inbound and
outbound trips counted. The manual verification data shall then be used
to calibrate the machine count data collected during either the a.m. or
p.m. peak hour of the site. The calibration factors developed through this
review shall then be used to adjust the daily machine counts. The
manual verification counts are intended to verify the correct operation of
the machine counters and as such are required to show proof of reducing
the margin of error (between inbound and outbound trips) originally
observed from the raw machine count data. The manual verification,
machine counts, and calibration must be documented in the study report
to show that the necessary quality control measures have been taken to
reflect accurate calculation of the trip generation rate. If a machine has a
margin of error greater than the allowable 10 percent, a recount is
required. Additional measures such as reviewing the counts by time and
day shall be taken to ensure that any anomalies that may have occurred
on a certain day that is out of the ordinary trend relative to the other days
be treated accordingly in terms of the necessary adjustments to the
machine counts.
The applicant shall include the machine count data in the study report.
All data are subject to review and acceptance by County staff, based on
currently accepted traffic engineering practice. County staff or the
County's consultant may visit the study site to observe the placement and
operation of the machine counters.
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If the applicant is unable to obtain machine and manual counts according
to the above requirements, he/she may repeat the entire count or may
elect to submit an explanation in writing to the County staff. The County
staff shall review the explanation and then may accept the data as is,
approve a partial recount, or require an entire recount. The County staff
shall provide this response in writing within ten (10) working days.
c. Collecting Trip Length and Percent New Trips Data
The origin/destination survey shall collect the following information:
. Date of the interview;
. Location of the interview;
. Name of the interviewer;
. Time of day of the interview;
. Origin of the interviewee's trip,
. Destination of the interviewee's trip, and
. Trip purpose.
The place of origin or destination shall be identified as accurately as
possible. The origin and destination shall be determined with one of the
following methods (listed from most preferred method to least preferred
method):
. The specific name and address of the origin and destination;
. The specific name of the origin and destination (mall, town, bank,
supermarket, subdivision, school, etc.)
. The intersection nearest to the origin and destination; or
. The major intersection nearest to the origin and destination.
The applicant shall employ interviewers that have a strong prior
knowledge of the places and major intersections in the community that
are most likely to be named by interviewees so the interviewers can
quickly recognize and record these responses when interviewees give
them, or solicit further detail in the response. In some cases, places
named by interviewees cannot later be pinpointed when the interview
forms are tabulated, disqualifying those interviews as observations. For
that reason, the applicant is prudent to conduct a quantity of interviews in
excess of the minimum required sample size.
The applicant shall use an interview form to record the interview
responses. This form shall be used to record the information identified
above. The applicant shall include copies of the completed interview
forms in the study report. Samples of acceptable interview forms are
included at the end of this appendix. These samples include fields to
record the data items listed above, as well as fields for calculating the trip
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length (at a later time), and fields for quality control. The applicant shall
include copies of the completed interview forms in the study report.
It is not acceptable to record the trip length as estimated by the
interviewee. The proper method to determine a trip length is to use a
scaled map to measure the shortest route between the site and the
reported places of origin and destination, or by using a geographic
Information system to measure the distance directly using a vehicle
odometer.
Note that only one person per car shall be surveyed. In the case of non-
residential land uses, it is important that all access point to the site are
covered (such as back entrances used by employees, etc.), and an
appropriate number of employees is also interviewed (at least 25 to 30
percent of the employees) in addition to the patrons.
Acceptable procedures to determine if a trip is classified as Primary,
Secondary, Diverted, or Captured, and to compute the assessable trip
length are described in "Measuring Travel Characteristics for
Transportation Impact Fees", WE Oliver, (ITE Journal, April 1991).
The applicant shall also include in the study report:
. The number of observations (useable interview responses);
. The average trip length, rounded off to 0.1 mile; and
. The percent new trips.
It is important to note any potential anomalies to the study site. For
instance, if there is a possibility of cut-thru traffic, the survey form shall be
created to accurately reflect this and trip generation as counted by the
machine counts shall be adjusted. Another example of potential site-
specific anomalies could be the presence of an exterior parking lot.
Patrons parking outside of the study site shall not be included in the
survey data.
d. Number of Interviews to Conduct
In determining a reasonable estimate of the trip length and percent new
trips, the applicant shall perform surveys at each of the three sites for a
minimum of 10 hours per site. The specific time period to be covered
shall be governed by the type of land use being surveyed and its typical
daily operations. An observation shall be considered valid if its origin and
destination are specific enough from which the trip length and type of trip
can be determined. Because captured trips do not have a measured
origin and destination, captured trips are not included in this calculation.
The specific required number of valid surveys is the number of surveys
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required to meet a 90% level of confidence at a plus/minus 15% level of
accuracy, or at least a total of 150 usable surveys for the study land use.
Upon completion of the surveys, whether there were sufficient number of
surveys shall be determined through the following formula, which
calculates the necessary sample size:
N = C2 X Z2
E2
Where:
N is the required sample size for the specific level of
confidence at the desired accuracy level;
C is the coefficient of variation as calculated by dividing
the sample mean trip length into the standard deviation of
the sample trip length;
Z is the normal distribution value statistic at the specific
level of confidence; and
E is the specific margin of error or level of accuracy.
The above formula is based on a methodology developed by Michael E.
Smith in "Design of Small-Sample Home Interview Travel Surveys",
Transportation Research Board 701, 1979.
e. Raw Data Must be Submitted
The applicant shall submit copies of the raw data to the County within 72
hours of the completion of the data collection phase.
3. Guidelines. The applicant shall use the information derived from the
traffic study to calculate an alternative impact fee. The results of the
Alternative Fee Calculation study shall be submitted to both the Impact
Fee Coordinator and the Transportation Services Division
4. SubmittinQ the Study Report. The applicant shall submit five (5) copies of
the study report to the Collier County Office of Transportation Services.
The study must be certified by a Professional Engineer registered in the
State of Florida or AICP.
5. Sufficiency and Fee Determination. The Impact Fee Coordinator,
Transportation Services Division Administrator, and/or the County's
Consultant shall review the Alternative Fee Calculation for suffiCiency
methodology, technical accuracy and findings, and shall make
recommendations concerning the amount of the impact fee and whether
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to accept the study.
This sufficiency determination shall be based on the statistical similarity
between the trip characteristics data collected as part of the Independent
Study with the ITE data and/or local data previously collected for that land
use, The steps in calculating the confidence level, as well as an example
computation are presented after the following recommended actions.
a. In cases when the applicant challenges the fee for an existing land
use or there is a disagreement between the applicant and the County
whether the applicant's development qualifies to be treated as a new land
use, if the Independent Study data results in a confidence level of 75
percent or less, implying that the data is statistically insignificant with
respect to the existing data set for the land use, then it is recommended
that the Independent Study data not be combined with the existing data
set for that land use. A statistical confidence of 75 percent or less
indicates that the data is not statistically different than the existing data
for that land use. Therefore, the applicant shall be assessed the impact
fee due as established in the County's adopted transportation impact fee
schedule.
b. When the Independent Study data shows a statistical confidence of
greater than 75 percent that the data is different than the previously
collected data for the land use, the County shall determine if the site falls
under an existing land use in the County's Transportation Impact Fee
Schedule. If the site does fall under an existing land use classification,
then the results of the Independent Study shall be combined with the
existing data set for that land use. The applicant shall then be assessed
the impact fee calculated based on this combined data set.
If the Independent Study data shows a statistical confidence of greater
than 95 percent that the data is different than the previously collected
data for the land use, the existing land use data will be revised to reflect
solely results of the alternative study or a new land use will be created as
appropriate.
If the County determines that there is a characteristic that differentiates
that site from existing land uses in the fee schedule or the site does not
fall under an existing land use category in the County's fee schedule,
then the County shall create a land use classification separate from the
land uses already included in the impact fee schedule. To facilitate this,
the trip characteristics data from the Independent Study sites shall be
utilized to calculate the appropriate impact fee for the new land use
category .
c. When the use is not clearly comparable to existing defined uses and
when there are not at least 3 local comparable sites, the applicant shall
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pay based on a rate that the applicant feels is appropriate, and conduct a
follow-up trip characteristics study of the actual site within three to five
years after the site is fully developed or open for business to verify or
revise the impact fee paid. Any adjustments to the impact fees shall be
made based on the rate applicable at the time of the initial study. Failure
to complete a follow-up study shall result in the applicant paying for
original fee based on the appropriate land use in the impact fee schedule
as determined by the Impact Fee Coordinator and Transportation
Services Division Administrator that was due at the time of the building
permit approval. The applicant shall be responsible for the cost of this
updated study.
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The following table summarizes the possible options:
Application Results of Final Action
Siqnificance Test
1) Existing Land Use a) Not significant (< a) The impact fee schedule
75%) does not change. Applicant
pays the fee indicated for
the use.
b) Significant at b) The alternative study
75% confidence data is combined into the
level data used to calculate the
fee schedule to obtain a
revised fee figure for the
existing land use.
c) Significant at c) The alternative study
95% confidence becomes the sole basis for
level the calculation of the impact
fee for the disputed land
use.
2) New Land Use a) Not significant a) The impact fee schedule
Category (the compared to land does not change. Applicant
applicant believes the use found to be pays the fee indicated for
proposed applicable by the use.
development is not County staff.
represented in the (<75%)
impact fee schedule, b) Significant at b) The alternative study
but the County 75% confidence data is incorporated into the
disagrees or has level compared to data used to calculate the
doubts) land use found to fee schedule to obtain a
be applicable by revised fee figure for the
County staff existing land use.
c) Significant at c) The alternative study
95% confidence becomes the sole basis for
level compared to the calculation of the impact
iand use found to fee for a new land use.
be applicable by
County staff
3) New Land Use The applicant Results of the study
(both the applicant conducts a trip become the basis of a new
and County agree characteristics land use to be included in
that it is not possible study for three the County's impact fee
to identify a land use sites. schedule.
for the proposed
development in the
existing fee
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schedule)
4) New Land Use
with no comparable
sites in Collier
County
N/A
The applicant shall pay the
fee based on a land use
category that the applicant
feels is representative and
conduct trip characteristics
study 3 to 5 years after the
operations begin to
verify/revise.
d, Z-Score This section demonstrates the steps necessary for
calculating a percent confidence using the z-score methodology, This
analysis is used to determine the statistical significance of any
differences between independent impact fee study data and data used to
produce the original transportation impact fee. It is important to note that
statistical comparisons using small sample sizes lack certainty; however,
the following application of the test still provides insight as to the
significance of the differences in trip characteristics data. In particular,
this procedure addresses combining data obtained from multiple sources-
e.g" trip generation rates from the Institute of Transportation Engineers
(ITE) source and trip length and percent new trips from local trip
characteristics studies,
The statistical test involves four steps. The first two steps involve
obtaining average VMT and variance for the data used in the adopted
transportation impact fee schedule and for the independent impact fee
study data. The z-score is then computed in the third step, followed by a
translation of the z-score into a confidence level in the fourth and final
step, The equation used to obtain the z-score is shown below, followed
by a detailed example of the z-score calculation.
z-score =
(- p, + Po)
~(a/ /n,)+(CJ',,' /no)
Where:
I', = Average VMT obtained by the independent study data
Po = Average VMT obtained using ITE and other studies used in the
original impact fee calculation
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,
al- = Variance of the VMT obtained by the independent study data
,
ao - = Variance of the VMT obtained using ITE and other studies used in
the original impact fee calculation
n I = Number of site locations in the independent study with complete
observations
no = Number of site locations in the original study with complete
observations
The following example explains the steps taken to obtain the z-score of
an independent impact fee study commissioned by a daycare land use
(ITE land use code 565). Therefore, trip rate calculation table headings
shall be in terms of a daycare. Note that if a study is conducted on a
retail land use site, for instance, trip rate table headings would be shown
as "1,000 square feet of Building," "Trips," and 'Trips per 1,000 square
feet of Building" respectively. All other table headings shall be identical to
those shown in the subsequent example.
Step 1: Obtaining Average VMT and Variance of the Original Data Used
in the Adopted Impact Fee Schedule.
Below is the formula to calculate the VMT:
VMT = Average Trip Rate x Average Trip Length x Average Percent New
Trips
Since the average trip rate, average trip length, and average percent new
trips are usually measured at different sites, and have different number of
observations, it is necessary to combine the variances associated with
each of the three variables to estimate the variance of the VMT. Below is
the generic formula used to calculate the variance of the VMT, denoted
,
a- (note that since these calculations shall be done by computer in Excel
or another program alike, the standard deviation (SD), as well as the
mean/average, shall be given and can then be plugged into the
equation):
SD2(x*y) = Mean2 (x) SD2 (y) + Mean2 (y) SD2 (x) + SD2 (x) SD2 (y)
The above equation would be applied twice, once to estimate the
standard deviation of the product of the trip rate and trip length, and a
second time to estimate the standard deviation of the product of the first
two variables and the percent new trips variable.
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Trip Rate
(ITE-LUC 565)
Trip Length
(Prior TOA Studies)
Students Trips Trips per Student
50 350 7.00
30 75 2,50
68 310 4.56
72 385 5,35
73 440 603
80 340 4.25
90 260 2,89
92 370 402
100 410 4.10
113 400 3.54
158 820 5.19
Site 1 1.90
Site 2 2.10
Site 3 2.60
Site 4 240
Average:
Standard Deviation:
Variance:
2.25 +-
0.31
010+-
Average:
Standard Deviation:
Variance:
449+-
1.33
1.77+-
Percent New Trips
(Prior TOA Studies)
,
VMT (VMTo , Jl 0, (J',:)
Site 1 70.0%
Site 2 75.0%
Site 3 89.0%
Site 4 82.0%
Average:
Standard Deviation:
Variance:
79.0% +-
0.08
0.01+-
Average: <7.98J
Standard Deviation: ~
Variance: ~
Calculations:
Average VMTo , Jl 0 = 4.49 x 2.25 x 79% = 7.98 vehicle miles
,
Variance ((J'" - ) is calculated in two steps:
,
(J'-
1) " (Rate x Length) = (4.492 x 0.10) + (2.252 x 177) + (1.77 x 0.10) =
11.15
,
2) (J',: (Rate x Length x % New Trips) = [(4.49 x 2.25)2 x 0.01] + [(0.792
x 11,15)] + (11.15 x 0,01) = 8,09 vehicle miles
Step 2: Obtaining Average VMT and Variance from the Independent
Study Data.
The example below illustrates the resulting values obtained from the data
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collected during the independent study. Note that the values shown for
the independent study variables VMT calculations shall simply obtained
using an Excel (or similar program) formula for variance and does not
have to be obtained using the extended method that was necessary for
the adopted VMT calculation.
Trip Rate
Trip Length
Students TriDs TriDs Der Studeot
198 633 3.20
)60 784 3.02
287 830 2.89
Site I 1.96
Site 2 4,00
Site 3 2.83
Percent New Trips
2
VMT (VMT" J.l " (J'/ )
Step 3: Obtaining a Z-Score.
Using the z-score equation from earlier, substitute in the values obtained
in Step 1 and Step 2.
(-5.34+7.98)
Z-score =
,J((0.1813)+(8.09/ 4)) = 1.59
Note:
no = 4 since, although there are many more observations for trip rate,
there are only 4 complete observations that include all the variables- trip
length, trip rate, and percent new trips.
n/ = 3 since there are 3 complete observations.
Step 4: Converting the Z-Score to a Confidence Level
Once the z-score is obtained, refer to the following Table 0-1 below to
locate the area under the standard normal distribution curve, illustrated in
Chart 0-1, associated with the specific z-score and multiply the
associated probability by 2. This area represents the probability that the
independent study data is observed outside the values of the original
impact fee study data.
Example:
A z-score of 1.59 is associated with 0.4441, or 44.41 %,
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44.4% x 2 = 89% Confidence Level
The resulting confidence level tells how confident we are that the data
from the independent study is significantly different from the data used in
the original impact fee equation and thus warrants, or fails to warrant, a
unique transportation impact fee. In this example, we are 89% confident
that the independent study data is significantly different than the data
used in the original impact fee equation.
A quick reference guide of z-scores and their associated confidence
levels is also shown in Table D-2.
Chart D-1
Standard Normal Z-Distribution
/
//
z
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Table D-1
Standard Normal Z-Distribution
z 0 0.01 0.02 0.03 0.D4 0.05 0.06 0.07 0.08 0.09
0 0 0.004 0.008 0.012 0.016 0.019 0.0239 0.0279 0.0319 0.0359
0.1 0.0398 0,0438 0.0478 0.0517 0,0557 0,0596 0,0636 0.0675 0.0714 0.0753
0.2 0,0793 0.0832 0.0871 0.091 0.0948 0.0987 0.1026 0,1064 0.1103 0,1141
0.3 0,1179 0.1217 0.1255 0.1293 0.1331 0,1368 0.1406 0.1443 0.148 0.1517
0.4 0,1554 0.1591 0.1628 0.1664 0.17 0.1736 0.1772 0.1808 0.1844 0.1879
0.5 0.1915 0.195 0,1985 0.2019 0.2054 0,2088 0.2123 0.2157 0.219 0.2224
0.6 0.2257 0.2291 0.2324 0.2357 0.2389 0,2422 0.2454 0.2486 0.2517 0.2549
(j.7 0.258 0.2611 0.2642 0.2673 0,2704 02734 0.2764 0.2794 0,2823 0.2852 .
U.. u,L881 O.L"I O.L"'" U.L""" 0.L9"5 O.'UL' u.,u51 u.,018 O,'IU" u.',"
G.B U.315" u.,,06 U,'LlL 0.'L38 U 'L64 u.'L09 U."315 0."j4 UjjOO UjjO"
1 0.3413 0.3438 0,3461 0.3485 0,3508 0,3513 0.3554 0.3577 0.3529 0.3621
1.1 0.3643 0.3665 0.3686 0.3708 0,3729 0.3749 0.377 0,379 0,381 0.383
1.2 0.3849 0.3869 0.3888 0,3907 0,3925 0.3944 0.3962 0,398 0,3997 0.4015
1.3 0.4032 0.4049 0.4066 0.4082 0.4099 0.4115 0.4131 0.4147 0.4162 0.4177
1.4 0.4192 0.4207 0.4222 0.4236 0.4251 0.4265 0.4279 0.4292 0.4306 0.4319
1.5 0.4332 0.4345 0.4357 0.437 0.4382 0.4394 0.4406 0.4418 0.4429 0.4441
1.6 U.440" U440j 0.4414 U.4404 u.44"0 u.4ouo U.4515 0.4525 0.45'5 0.4545
1.7 0.4554 0.4564 0,4573 0.4582 0.4591 0.4599 0.4608 0.4616 0.4625 0.4633
1.6 U.4041 U.404" U.4000 U.4004 U.4011 u.4010 u.4006 0.469' U.4699 04706
1.B 0.4713 0,4719 0.4726 0.47'2 0.4738 0,4744 0.475 0.4756 0.4761 0.4767
~ 0.4772 0.4778 0.4783 0.4788 0.4793 I 0.4798 UAOU' u.4ouo U.40IL u.40'17
2.1 0.4821 0.4826 0.483 0.4834 0.4838 0.4842 0.4846 0.485 0.4854 0.4857
~.. 0,4861 0.4884 0.4868 0.4871 0.4875 10.4878 0.4001 0.4884 0.4887 0.489
". u.40", U.40,", u.4090 u.4"u1 0.4"U4 UA>JUb U.4"U" U.4"" U.4"', U.4910
2.4 0,4910 0.49" 0.4922 0.4925 0.4927 0.49"9 0.4931 0.4932 0.4934 0.4936
2.5 U.49,0 U.494 U.4941 U.494, u.4945 10.4940 0.4948 I 0.4949 0.4951 0.4952
2,5 0.495, U.4955 0.4900 0.495r 0.4959 0496 0.4961 I 0.4962 0.4963 10.4964
2.7 0.4965 0.4966 0.4967 0.4968 0.4969 0.497 104"11 I U 497L u.4"73 u,4"14
2.8 0.4974 0.4975 0.4976 0.4977 0.4977 0.4978 0.4979 0.4979 0.498 0.4981
2.9 0,4981 0.4982 0.4982 0.4983 0.4984 0.4984 0.4985 0.4985 0.4986 0.4986
3 0.4987 0.4987 0.4987 0.4988 0.4988 0.4989 0.4989 0.4989 0,499 0,499
3.1 0.499 0.4991 0.4991 0.4991 0.4992 0.4992 0.4992 0.4992 0.4993 0.4993
3.2 0.4993 0.4993 0.4994 0.4994 0.4994 0.4994 0.4994 0.4995 0.4995 0.4995
3.3 0.4995 0.4995 0.4995 0.4996 0.4996 0.4996 0.4996 0.4996 0.4996 0.4997
'.4 0.4997 0.4997 0.4997 0.4997 0.4997 10.4""1 0.4997 0.4997 0.4""7 0.4"98
Table D-2
Quick Reference Guide
Z'8core % Confidence
2.55 99%
1.96 95%
1.65 90%
1.17 76%
1.15 75%
0.67 50%
0.00 0%
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6. Adoption of Fee. The Impact Fee Coordinator and the Transportation
Services Division Administrator shall make the final recommendation of
the impact fee amount for consideration by the Board of County
Commissioners (BOCC) as required by the adopted impact fee
ordinance.
If the study is conducted by the applicant, the applicant shall submit all of
the data to the County regardless of the resulting impact fee. If the
resulting impact fee is higher, the County will reimburse the applicant for
the expense associated with conducting and reviewing the trip
characteristics study.
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Sample Survey Forms
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Appendix D 1
Transportation Impact Fee
Alternative Impact Fee Study Guidelines and Procedures
CURRENTLY ADOPTED GPC RATES
FOR IMPACT FEE STUDIES
Hourly Rates and Reimbursable Schedule
Professional
Hourly Rate
Principle in Charge
$194.00
$154.00
Project Manager
Sr. Engineer/Planner
$130.00
Planner
$ 7400
$ 69.00
Graphics/Editor/Tech.
Admin/Clerical
$ 65.00
EXHIBIT B