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