Title: City of San Antonio UDC Changes to Traffic Impact Analysis (TIA) Requirements
1City of San Antonio UDC Changes to Traffic Impact
Analysis (TIA) Requirements
September 30, 2009 South Texas ITE Meeting
Kerri M. Collins, P.E., PTOE Pape-Dawson
Engineers, Inc.
2What is the purpose of a TIA?
- Identify traffic impacts associated with a
specific development and identify mitigation
measures that address those impacts.
3What value does a TIA provide to the developer?
- project approvals per UDC
- Identifies traffic problems.
- Establishes basis for developers obligation for
improvements. - Identifies future transportation needs.
The Rim
4Ordinance 2009-05-21-0429
- The developer will bear a portion of the costs
of municipal infrastructure improvements in an
amount that is roughly proportionate to the
proposed development.
5Proportionality Spreadsheet
- Provided by the City.
- Updated by the City.
- Establishes maximum financial obligation
developer must contribute towards mitigation of
traffic impacts. - Can be challenged in appeal process.
- TIA identifies impacts, mitigation improvements
and cost.
6Proportionality Spreadsheet Examples
- 14,000 SF Pharmacy -
- up to 200,000
- 3,500 SF Fast Food Restaurant up to 195,000
- 100,000 SF Retail
- up to 800,000
- 80,000 SF Supermarket
- up to 1.75 Million
- 500 Unit Apartment Complex -
- up to 1 Million
- 500 Single Family Homes
- up to 1.6 Million
7Its Not Just a TIA Anymore
- TIA Proportional Mitigation Determination
Report are required for Applications for MDP,
Permitting, Rezoning when any of the following
applies - Project generates 76 or more PHT
- Change to existing TIA or existing zoning results
in increase of 76 or more PHT or 10 of total pk
hr trips - Building permit submission shows 5 or more
increase in PHT compared with TIA - TIA is over 5 years old
- Access points in original TIA are reduced or
relocated.
8When is a TIA Required?
- Today
- If 100 peak hour trips TIA Worksheet
- If 101 to 500 peak hour trips Level 1 TIA
- If 501 to 1,000 peak hour trips Level 2 TIA
- If gt 1,000 peak hour trips Level 3 TIA
- On March 1, 2010
- If 75 peak hour trips or less TIA Form w/Turn
Lane Evaluation Required - If 76 peak hour trips or more TIA is required.
9A Study Level TIA is Needed for
- A site that is gt 500 Acres and
- An application is being made for an MDP or PUD
10Density/Land Use Thresholds
Land Use Today Level 1 TIA March 1, 2010 Full TIA
Land Use Density for 500 Peak Hr Trips Density for Over 75 Peak Hr Trips
Single Family Homes 490 units 75 units
General Office 300,000 SF 50,000 SF
Retail 125,000 SF 20,000 SF
Fast Food Restaurant 10,000 SF 1,800 SF
11TIA Study Area per UDC
Category Impact Area
Any TIA 1.5-mile distance from site boundary. Measured along road network.
Category Impact Area
Level 1 or 2 TIA ¼ mile radius from site boundary.
Level 2 TIA up to a maximum of 1-mile radius.
Level 3 TIA 1-mile radius from site boundary.
12Intersections Are Included if Both Conditions Are
True
- 76 or more peak hour trips entering or exiting
the intersection and - the intersection is within 1.5 miles of the site
boundary, measured along the road network.
13Study Intersections
250
250
14Other Relevant Changes
- Peak hours Can be AM, PM, Midday, Afternoon,
Saturday, depending on type of use. - Project Phasing maximum of 7 years per phase.
- TIA Scoping Meeting with Development Services and
Public Works is required to review assumptions - Trip generation, distribution assignment.
- Study area and intersections
- Pass-by/Internal Trip Credits
- Peak hours
- Analysis Scenarios
15How do we measure an impact?
- We compare the No Build Condition results to the
Build Condition results.
Traffic generated by this project
Measurement of Impacts
Traffic from other nearby projects and population
growth
Existing traffic
16Impact Definition for Study Intersections
- Today
- for intersections in site and along boundary
must improve to No Build LOS if Build LOS is D,
E, or F.
- March 1, 2010
- for ALL signalized study intersections must
maintain No Build LOS C or improve to within 20
of No Build delay if Build LOS is D, E, or F.
- March 1, 2010
- for unsignalized intersections must maintain
No Build LOS C or improve to within 10 of No
Build delay if Build LOS is D, E, or F.
17Mitigation Measures
- Today
- improvements for intersections in site and along
boundary only. If No Build is LOS F, no
mitigation required.
- March 1, 2010
- improvements at intersections with impacts
both on and off-site. - if improvements are deemed infeasible then
non-compliant intersection.
18Additional Submission Requirements
- Rough Proportionality Spreadsheet
- Approximate total cost of improvements including
design, engineering and construction to be
provided in the TIA.
19TIA Content Requirements
- Detailed content per Section 35-B122.
- Saturday peak hour analysis must be included for
retail use or weekend generator. - Land uses with peaks outside of weekday AM, PM
should be included, i.e., schools. - Seasonal adjustment factor must be applied to
count data collected during non-school periods. - Separate trip distributions for land uses with
different travel patterns. i.e., retail vs.
office/residential.
20Turn Lane Requirements
- Today
- Right and left-turn lanes required at site
access points with 60 peak hour entering right or
left-turn vehicles.
- March 1, 2010
- Requirement is 50 peak hour or 500 daily right or
left-turn vehicles. - If median, left-turn bay required regardless of
left-turn volume. - Turn lanes are required where safety issue is
present.
21Turn Bay Design
- As of August 20, 2009
- Design should be in accordance with TxDOT design
manual for minimum taper and storage length. - Deceleration length to be determined by either
method - TxDOT Design Manual 20 mph differential speed
from roadway design speed. or - Calculation of stopping sight distance based on
design topographic conditions and differential
speed of 10 mph.
22Median Spacing Requirements
- Prior UDC
- 400 spacing between median openings.
- As of August 20, 2009
- Arterial from freeway 660 from the intersection
- Arterial to Arterial 500 from the intersection
and 400 thereafter - Freeway/Arterial to Collector 400 from
intersection and 400 thereafter
23Intersection Spacing
- Prior UDC
- Centerline offset minimum of 125
- As of January 15, 2009
- Local A with Local A 125 centerline offset.
- Streets intersecting with a collector 150
centerline offset or minimum distance needed for
turn lane. - Collector with Collector 200 centerline offset
or minimum distance needed for turn lane. - Collector with Arterial 400 centerline offset
or minimum distance needed for turn lane.
24What is the Traffic Engineers role?
- To foster transportation solutions that meet the
requirements of the public agency, that adhere to
acceptable engineering standards and do not
exceed the obligation required of the developer. - Develop solutions in the best interest of the
client and public
25Questions?