N Gateway 4-SY130111DeShazo Group, Inc.
January 11, 2013
Driveway Analysis for
Emerus Emergency Hospital
~ DeShazo Project No. 13002 ~
Table of Contents
INTRODUCTION ....................................................................................................... 1
Project Description .......................................................................................................... 1
Purpose ............................................................................................................................ 2
TRAFFIC ANALYSIS ................................................................................................ 2
Trip Generation and Mode Split ...................................................................................... 2
Trip Distribution and Assignment .................................................................................. 3
Hourly Driveway Volumes ............................................................................................... 4
Deceleration Lane Criteria............................................................................................... 4
CONCLUSIONS ........................................................................................................ 5
APPENDIX
Proposed Emerus Emergency Hospital
Driveway Analysis
Table of Contents
Traffic. Transportation Planning. Parking. Design.
400 S. Houston Street, Suite 330
Dallas, TX 75202
ph. 214.748.6740
deshazogroup.com
Technical Memorandum
Joe Roberts
To:Emerus Holdings, Inc.
Brian Jaffe, P.E.
Cc:Dowdey, Anderson & Associates, Inc.
Steve E. Stoner, P.E., PTOE
From:DeShazo Group, Inc
January 11, 2013
Date:
Analysis for the Emerus Emergency Hospital in Coppell, Texas
Re:
Driveway
DeShazo Project No. 13002
INTRODUCTION
The services of (DeShazo) were retained by to
DeShazo Group, IncEmerus Holdings, Inc.
conduct a traffic analysis to evaluate the need for a deceleration lane to be construction at a
proposed driveway on Denton Tap Road in Coppell, Texas. The analysis is in conjunction
with the proposed development of an Emerus Emergency Hospital and other pad sites on
the subject property located on the northwest quadrant of SH-121 Westbound Frontage
Road (WBFR) and Denton Tap Road in Coppell, Texas. A site location map is provided for
reference in .
Exhibit 1
is an engineering consulting firm providing licensed engineers s
DeShazo
of traffic/transportation engineering.
Project Description
The 12.36-acre property is bound on the south by the SH-121 Westbound Frontage Road
(WBFR) and on the east by Denton Tap Road; residential uses are located north of the site.
Zoning for the (PD-
240-HC). The property is served by four site drivewaystwo on Denton Tap Road and two
on the WBFR. The conceptual plan provided for nine lots containing various commercial
uses. A copy of the 2009 approved conceptual plan is provided i the .
Appendix
Proposed Emerus Emergency Hospital
Driveway Analysis
Appendix
DeShazo Group, Inc.
January 11, 2013
Currently, Lots 5, 6, and 9 are developed and in operation. The
development is located on a 6.127-acre portion of the site (referenced herein
Lots 1, 2, 3, and 4. An updated Concept Plan are also
provided in the
Appendix.
The proposed medical use development includes approximately 40,000 square feet of floor
area in a two-story building the lower floor consists of an emergency hospital institution,
and the upper floor contains medical offices. A detailed site plan for the Project as provided
by Dowdey, Anderson & Associates, Inc. is provided in the .
Appendix
Purpose
Based upon the development scenario approved in the 2009 Concept
deceleration lane on the southernmost driveway on Denton Tap Roa
osed development scenario
with the Emerus project, validation of the need for the decelera
been proposed.
The purpose of this analysis is to update the projected traffic conditions projected for
Driveway 2 based upon the new development scenario and evaluate the need for the
deceleration lane. Since the City of Coppell does not have specific criteria for co
of deceleration lanes, the guidelines developed by the Texas Department of Transportation
(TxDOT) and published in . The
findings of the analysis will be provided to the City of Coppell for consideration of
deferring or removing the requirement for the deceleration lane .
TRAFFIC ANALYSIS
The analysis presented in this report was designed to calculate the projected inbound site
traffic volume at Driveway 2 during the traditional AM and PM weekday peak hours of
adjacent street traffic. Based upon the hourly volume, consideration of the need to construct
a deceleration lane at the subject driveway will be requested of the City of Coppell. The
projected driveway volumes were calculated using the methodology
Trip Generation and Mode Split
Trip generation for the Project was calculated using the Institu
Engineers (ITE) Trip Generation manual (8 Edition). ITE Trip Generation is a compilation of
th
actual traffic generation data by land use as collected over sev
sources across the country, and it is accepted as the standard mp
generation volumes for various land uses where sufficient data eno
special adjustments (i.e., consideration of vehicle occupancy and other factors
that may affect site-generated traffic volume) are required.
Trip generation is summarized in trip ends a trip end is a one-way vehicular trip entering
or leaving a site (i.e., one vehicle arriving and departing repr
Table 1
Proposed Emerus Emergency Hospital
Driveway Analysis
Appendix
DeShazo Group, Inc.
January 11, 2013
provides a summary of the calculated trip ends generated by each lot on the property.
Excerpts from Trip Generation are provided in the
Appendix.
Table 1. Projected Trip Generation Summary
(Cumulative for All Lots and All Driveways)
AM Peak Hour of PM Peak Hour of
School Traffic School Traffic
Lot No. Land Use Quantity
Total In Out Total In Out
1 Hospital* 33 Employees 24 17 7 60 19 41
1 Medical/Dental Office* 20,000 SF 46 36 10 68 18 50
5 Restaurant (Existing) 6,468 SF 75 39 36 72 42 39
6 Medical/Dental Office (Existing) 4,550 SF 10 8 2 19 5 14
7 Restaurant (Future)** 2,450 SF 28 15 13 27 16 11
7 Specialty Retail (Future)** 4,550 SF 0 0 0 32 14 18
8 Medical/Dental Office (Future)** 4,000 SF 9 7 2 17 5 12
9 Medical/Dental Office (Existing) 8,100 SF 19 15 4 31 8 23
211 137 74 326 127 199
TOTAL
* Trip generation for the proposed Emerus development is based upon assessment of traffic
characteristics as described by the Owner.
** Future uses are assumed but are based upon similar assumptions used in the prior studies.
Trip Distribution and Assignment
Site traffic assignment is the exercise of estimating the orient-
generated trips by various travel routes. Traffic assignment is
upon professional judgment that considers such factors as trip characteristics (trip length,
trip purpose, travel time, etc.), roadway characteristics (capac
character of environment), regional demographics, etc.
Traffic for the proposed redevelopment was distributed and assigned to the study area
roadway network based upon consideration of the factors listed aThough the area of
concern for this study is specifically related only to Driveway it was necessary to assign
traffic volume to each driveway; and since each lot has a different level of accessibility from
Driveway 2, the traffic assignment for each lot was projected independently. A detailed
graphical summary of estimated site traffic assignment is provided in .
Exhibit 2
Proposed Emerus Emergency Hospital
Driveway Analysis
Appendix
DeShazo Group, Inc.
January 11, 2013
Hourly Driveway Volumes
To determine the inbound peak hour traffic volume at Driveway 2 generated by site
development, the contribution of traffic generated by each lot (summarized in )
Table 1
multiplied by the corresponding traffic assignment value at Driveway 2 (summarized in
) was tabulated. A summary is provided in .
Exhibit 2Table 2
Table 2. Driveway 2 Peak Hour Traffic Volumes
AM Peak Hour PM Peak Hour
Inbound Inbound
Net Peak Net Peak
Total Traffic Total Traffic
Hour Hour
Inbound Assignment Inbound Assignment
Volume at Volume at
Volume at Volume at
Driveway 2 Driveway 2
Driveway 2 Driveway 2
Lot 1 53 35% 19 37 35% 13
Lot 5 39 40% 16 42 40% 17
Lot 6 8 40% 3 5 40% 2
Lot 7 15 10% 2 30 10% 3
Lot 8 7 10% 1 5 10% 1
Lot 9 15 0% 0 8 0% 0
TOTAL 137 -- 41 127 -- 36
The net hourly volume entering the site at Driveway 2 is project
during the AM peak hour and 36 vehicles during the PM peak hour.
Deceleration Lane Criteria
The City of Copell does not provide specific criteria for installation of right-turn
deceleration lanes. In the absence of such criteria, DeShazo co
of Transportation (TxDOT) guidelines published in Chapter 2, Tab-3 of the Access
Management Manual (2011). The thresholds for which right-turn deceleration lanes should
be considered are summarized in
Table 3.
Table 3. TxDOT Right-Turn Deceleration Lane Guidelines
Posted Speed Driveway Volume
Limit Threshold (Inbound)
> 45 MPH > 50 vehicles per hour
< 45 MPH > 60 vehicle per hour
NOTE: Other considerations for installation of right-turn deceleration lanes are
provided in Table 2-3 of the Access Management Manual. [None of the additional
considerations appear to be applicable for this case.] The full text of this table is
Appendix
provided in the .
Proposed Emerus Emergency Hospital
Driveway Analysis
Appendix
DeShazo Group, Inc.
January 11, 2013
The currently posted speed limit on the Denton Tap Road in the vicinity of the site is 45,
hence the applicable driveway volume threshold for considering i
deceleration lane is 50 vehicles per hour.
CONCLUSIONS
The analysis performed herein determined that, at the highest pe
site buildout, less
than fifty (50) vehicles per hour. Under these conditions, the TxDOT deceleration lane
driveway volume threshold is not satisfied. Though the City of Copell has no published
requirements for installation of a deceleration lane, the finding of this analysis is that a
deceleration lane is not warranted. It is the recommendation of DeShazo that the
requirement for a deceleration lane at Driveway 2 of the subject property, which serves the
proposed Emerus Emergency Hospital and other lots, be removed.
END OF MEMO
Proposed Emerus Emergency Hospital
Driveway Analysis
Appendix
GRAPHICSCALE
STATEREGISTRATIONNUMBER:F-399
GRAPHICSCALE
SITEDATASUMMARYTABLE
FLOODSTATEMENT
NOTES
STATEREGISTRATIONNUMBER:F-399
Chapter 2 Ï Access Management StandardsSection 3 Ï Number, Location, and Spacing of Access
Connections
Table 2-2: Other State Highways Connection Spacing Criteria
(1)(2)(3)
Other State Highways Minimum Connection Spacing
Posted Speed (mph)Distance (ft)
30200
35250
40305
45360
> 50425
(1) Distances are for passenger cars on level grade. These dista
adjusted for downgrades and/or significant truck traffic. Where present or
projected traffic operations indicate specific needs, consideration may be
given to intersection sight distance and operational gap acceptance measure-
ment adjustments.
(2) When these values are not attainable, refer to the variance process as
described in Chapter 2, Section 5.
(3) Access spacing values shown in this table do not apply to ru
outside of metropolitan planning organization boundaries where t
if any, potential for development with current ADT levels below
Access connection spacing below the values shown in this table m
approved based on safety and operational considerations as deter
TxDOT.
Corner clearance refers to the separation of access connections from roadway intersections. Table
2-2 provides minimum corner clearance criteria.
Where adequate access connection spacing cannot be achieved, the permitting authority may allow
for a lesser spacing when shared access is established with an abutting property. Where no other
alternatives exist, construction of an access connection may be allowed along the property line far-
thest from the intersection. To provide reasonable access under these conditions but also provide
the safest operation, consideration should be given to designing the driveway connection to allow
only the right-in turning movement or only the right-in/right out turning movements if feasible.
Auxiliary Lanes
This subsection describes the basic use and functional criteria associated with auxiliary lanes. Aux-
iliary lanes consist of left-turn and right-turn movements, deceleration, acceleration, and their
associated transitions and storage requirements. Left-turn movements may pose challenges at
driveways and street intersections. They may increase conflicts, delays, and crashes and often com-
plicate traffic signal timing. These problems are especially acute at major highway intersections
Access Management Manual2-13 TxDOT 07/2011
Chapter 2 Ï Access Management StandardsSection 3 Ï Number, Location, and Spacing of Access
Connections
where heavy left-turn movements take place, but also occur where left-turn movements enter or
leave driveways serving adjacent land development. As with left-turn movements, right-turn move-
ments pose problems at both driveways and street intersections. Right-turn movements increase
conflicts, delays, and crashes, particularly where a speed differential of 10 mph or more exists
between the speed of through traffic and the vehicles that are turning right.
Table 2-3 presents thresholds for auxiliary lanes. These thresholds represent examples of where left
turn and right turn lanes should be considered. Refer to the TxDOT Roadway Design Manual,
Chapter 3, for proper acceleration and deceleration lengths.
Table 2-3: Auxiliary Lane Thresholds
(5)
Right Turn to or from Property
Median TypeLeft Turn to or from Property
AccelerationDecelerationAccelerationDeceleration
Non-Traversable (2)AllRight turn egress > > 45 mph where right
(Raised Median)200 vph (4)turn volume is > 50
vph (3)
where right turn
45
volume is > 60 vph (3)
Traversable (Undi-(2)(1)Same as aboveSame as Above
vided Road)
(1) Refer to Table 3-11, TxDOT Roadway Design Manua l, for alternative left-turn-bay operational considerations.
(2) A left-turn acceleration lane may be required if it would provide a benefit to the safety and operation of the road-
way. A left-turn acceleration lane would interfere with the left-turn ingress movements to any other access
connection.
(3) Additional right-turn considerations:
Conditions for providing an exclusive right-turn lane when the r
indicated in Table 2-3:
High crash experience
Heavier than normal peak flow movements on the main roadway
Large volume of truck traffic
Highways where sight distance is limited
Conditions for NOT requiring a right-turn lane where right-turn volumes are more than indicated in Table 2-3:
Dense or built-out corridor where space is limited
Where queues of stopped vehicles would block the access to the right turn lane
Where sufficient length of property width is not available for the appropriate design
(4) The acceleration lane should not interfere with any downstream access connection.
The distance from the end of the acceleration lane taper to the next unsignalized downstream access connection
should be equal to or greater than the distances found in Table
Additionally, if the next access connection is signalized, the distance from the end of the acceleration lane taper to
the back of the 90th percentile queue should be greater than or equal to the distances found Table 2-2.
(5) Continuous right-turn lanes can provide mobility benefits both for through movements and for the turning vehi-
a
cles. Access connections within a continuous right turn lane should meet the spacing requirements found in Table 2-
2. However, when combined with crossing left in movements, a continuous right-turn lane can introduce additional
operational conflicts.
Access Management Manual2-14 TxDOT 07/2011