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PERFORMANCE BASED PRACTICAL DESIGN
DOT’S FACE INCREASING CHALLENGES
We learned from those who taught us how and why we follow the standards…
There are valid reasons that tell us we now need to work differently: FundingStaff ResourcesAging infrastructureEnvironmental considerationsAvailability of reliable data and information Technology
ENGINEERING CULTURE
PBPD is a decision making approach that helps agencies better manage
transportation investments and serve system-level needs
and performance priorities with limited resources.
WHAT IS PBPD?
New Policy, Regulation, or RequirementOpportunity to disregard long-term needs:For short term cost savingsOverlooking future development
Compromising on safety, user needs (bike, ped, etc.), or accommodation of freight to save money
PBPD IS NOT:
COMMON THEMES OF PBPD:
Project decisions are based on critical examination of geometric elements Select/size elements that serve priority needsReduce or eliminate those that don’t
Utilizes relevant, objective data to inform decisionsChoices made to serve project priorities
while trying to save moneyProject savings benefit System Needs
PBPD focuses on performance improvements that benefit both project and system needs.
Agencies make sound decisions based upon performance analysis.
By scrutinizing each element of a project’s scope relative to value, need, and urgency, a PBPD approach seeks a greater return on infrastructure investments.
NOTABLE ATTRIBUTES
PBPD strengthens the emphasis on planning-level corridor or system performance needs and objectives when planning, scoping and developing individual projects.
PBPD can be implemented within the Federal-aid Highway Program regulatory environment utilizing existing flexibility.
PBPD does not eliminate, modify or compromise existing design standards or regulatory requirements.
NOTABLE ATTRIBUTES
PBPD – OVERLAPPING
Context Sensitive Solutions
Value EngineeringSystem Performance
Existing Typical 9’ Lanes 3’ Shoulders
Proposed Initial Typical 12’ Lanes4’ Paved Shoulder 4’ Aggregate Shoulder
11’ Lane 2’ Paved Shoulder1’ Aggregate Shoulder
PRACTICAL DESIGN EXAMPLE
Practical Design SavingsItem Original Cost Practical Cost Savings
Pavement DesignReduce driving lane from 12' to 11' $3,600,000 $3,300,000 $300,000
Minimize Underdrain Depth and locations $120,000 $60,000 $60,000
Shoulder DesignReducing shoulder Aggregate width 4' to 1' $160,000 $40,000 $120,000
Reduce to 3:1 Side Slopes and V‐bottom ditches $775,000 $525,000 $250,000
UtilitiesRelocate 8" gas line to lower elevation $3,000,000 $500,000 $2,500,000
Move OH utilities inside Clear Zone:Reduce trees to be removed $232,000 $132,000 $100,000
Reduce area of mitigated wetlands $500,000 $400,000 $100,000 Reduce number of mitigated trees $50,000 $10,000 $40,000
StructuresModify instead of replace most large structures $700,000 $200,000 $500,000
Structure Removal $120,000 $20,000 $100,000 Minimizing Cover Depth at Crest Curves $40,000
Structure Backfill $60,000 $20,000 $40,000
TOTAL PROJECT SAVINGS: $4,150,000
PERFORMANCE BASED PRACTICAL DESIGN EXAMPLE
PERFORMANCE BASED PRACTICAL DESIGN EXAMPLE
PERFORMANCE BASED PRACTICAL DESIGN EXAMPLE
PERFORMANCE BASED PRACTICAL DESIGN EXAMPLE
Case Study:
Evaluation of PennDOT I-70
Project using IHSDM
Case Study
Alt. 2a: New Interchange
Alt. 2a: New Interchange
Alt. 3: Local road improvements
(No Interchange)
Alt. 3: Local road improvements
(No Interchange)
Case Study
ALL ENGINEERING CHOICES HAVE TRADE‐OFFS
Cost
Val
ue
(Ope
rati
ons,
Saf
ety,
Eff
icie
ncy
etc.
)
19
Min
imum
Sta
ndar
ds
Below Design Criteria
Meets or Exceeds Design Criteria
Same Cost, Better Value
Same Value, Lower Cost
Which One Would You Choose?
Out of alternatives 1-5, which predicted crash performance comes out on top?
TEST YOUR KNOWLEDGE: WIDENING FREEWAY FOR CAPACITY
Alternative
No. of General Purpose
LanesTotal K A B C PDO
Outside Shoulder WidthLane Width
14
12
10
4 11 11 12 12
12 12 12
11 11 11
11 11 11
11
8
11
11
11 11 11
11 11 11 11
10
12 12 12 12
2
12
Inside Shoulder Width
178.1
12
8
6
4
254.4 0.9 2.6 18.6 54.2Full Build 4 12 12
201.3
298.5 1.4 3.0 22.9 63.6 207.5
292.2 1.4 3.0 22.9 63.6
Estimated average crash freq. during Study Period, crashes/yr:
Estimated Crash Statistics
189.3
286.4 1.5 3.0 22.9 63.8 195.2
281.2 1.5 3.1 23.1 64.3
293.9 1.3 3.1 22.9 65.3 201.3
293.6 0.8 2.3 16.8 63.4 210.1
Alt. 5 4
Alt. 3 4
Alt. 4 4
Alt. 1 4
Alt. 2 4
NoBuild 3
Alternative
No. of General Purpose
LanesTotal K A B C PDO
Outside Shoulder WidthLane Width
14
12
10
4 11 11 12 12
12 12 12
11 11 11
11 11 11
11
8
11
11
11 11 11
11 11 11 11
10
12 12 12 12
2
12
Inside Shoulder Width
178.1
12
8
6
4
254.4 0.9 2.6 18.6 54.2Full Build 4 12 12
201.3
298.5 1.4 3.0 22.9 63.6 207.5
292.2 1.4 3.0 22.9 63.6
Estimated average crash freq. during Study Period, crashes/yr:
Estimated Crash Statistics
189.3
286.4 1.5 3.0 22.9 63.8 195.2
281.2 1.5 3.1 23.1 64.3
293.9 1.3 3.1 22.9 65.3 201.3
293.6 0.8 2.3 16.8 63.4 210.1
Alt. 5 4
Alt. 3 4
Alt. 4 4
Alt. 1 4
Alt. 2 4
NoBuild 3
Which One Would You Choose?
KEY REPORTS
THE 13 CONTROLLING CRITERIA ARE PROPOSED TO CHANGE…
22
FHWA proposes to eliminate the following controlling criteria: Bridge Width Vertical Alignment Lateral Offset to Obstruction
To improve clarity, FHWA proposes to rename the following existing controlling criteria: Horizontal Alignment → Horizontal Curve Radius Grade → Maximum Grade Structural Capacity → Design Loading Structural Capacity
WWW.REGULATIONS.GOV
Controlling Criteria FHWA Proposes To Retain for Roadways on the NHS With a Design Speed Equal to or Greater Than 50 mph (80 km/h):
1. Design Speed*2. Lane Width3. Shoulder Width4. Horizontal Curve Radius5. Superelevation6. Stopping Sight Distance 7. Maximum Grade8. Cross Slope9. Vertical Clearance10.Design Loading Structural Capacity*
WWW.REGULATIONS.GOV
*Design Speed & Design Loading Structural Capacity is proposed to apply to all NHS roads regardless of Design Speed
Comments must be received onor before December 7, 2015
FHWA is prepared to support States as they develop projects with a system performance mindset
using data-driven methods
FHWA WILL BE A GOOD PARTNER
QUESTIONS