Investment Trade-Off Analysis:Highway Economic Requirements

System (HERS)

Data Palooza WorkshopMay 9, 2013

Rabinder Bains, FHWA – Office of Policy and Government Affairs

HERS CapabilitiesProjects overall conditions & performance of

nation’s highways at alternative potential levels of investment.

Estimates investment needs relative to user-specified targets - e.g. average speed, minimum BCR (benefit-cost ratio)

Bridge replacement is estimated using NBIAS model

HERS could be used to develop fiscally constrained performance targets or estimate investment levels to reach desired targets

2

HERS EvolutionDeveloped in the early 1990s as replacement

for Highway Performance Monitoring System Analytical Process

Used to run scenarios for the Condition and Performance Report to Congress and budget analysis

Evaluates investments using engineering & economic (benefit-cost) criteria

HERS-ST is the model’s state-level version, developed in early 2000s

3

HPMS DatabaseLimited to highways eligible for Federal aid—

arterials, urban collectors, and rural major collectors

Local roads & rural minor collectors not included because generally ineligible for Federal aid

Approximately 10% of the Federal-aid highways are sampled

Detailed data on sample of highway sections used in HERS

4

Evaluated ImprovementsPavement preservation

RehabilitationReconstructionResurfacing, etc.

Capacity expansion

Adding lanesMajor wideningNew highway construction

5

Operational improvements• Ramp metering, variable speed limits,

incident management systems, upgraded traffic signals, etc.

• HERS estimates incidence and impacts of current and future deployments but does not subject these deployments to BCA.

6

Non-modeled improvementsSafety improvements

• Rumble strips• Safety edges• Median treatments• Signalized intersection improvements• Guardrails, etc.

Bridge Replacement, excluding expansionOther improvements –e.g. landscaping

7

HERS Benefit-Cost AnalysisMonetizes benefits from reductions in:

Travel timeVehicle operating costsCrashes EmissionsHighway maintenance costs

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9

HERS Analytical Steps

Traffic Forecast

Simulate FutureConditions and Performance

IdentifyDeficiencies

Identify Potential Section Improvements

Select System Improvements

CurrentConditions

Current Condition & Traffic ForecastOver 119,000 Highway Segments in HPMS

PavementGeometryTraffic VolumeCapacity

Future Travel DemandBase YearSpecified Future YearAdjusted by Travel Demand Elasticity

Simulate Future Conditions and Performance

Pavement and CapacityPavement Deterioration

Based on AASHTO ProcedureCapacity Calculations

Based on TRB’s Highway Capacity Manual

Pavement condition and capacity affect user travel costs, which feed into future traffic forecast through the travel demand elasticity

Identify DeficienciesSection Evaluation

Pavement Condition - good, acceptable, poor Surface Type – asphalt, concrete, unpaved Volume/Capacity, Lane Width Right Shoulder Width, Shoulder Type Horizontal Alignment, Vertical Alignment

Deficiency Levels Trigger Levels for HERS to Consider

ImprovementsSeriously Deficient LevelUnacceptable Levels (not used by FHWA)

Identify Potential Section ImprovementsHighway Improvements

Pavement None, Resurface or reconstruct

Widening None, widen shoulder, widen lanes, add

lanes

Alignment No Change, Improve Curves, Improve

Grades, Improve Grades & Curves

Identify Potential Section ImprovementsImprovement Evaluation

Estimate Reductions in Road User Costs Travel time Vehicle operating costs Safety

Estimate Reductions in Highway Agency Costs Maintenance costs Residual value

Estimate Reductions in Societal Costs Emissions

Estimate Improvement CostsEstimate a benefit cost ratio (ratio of user , agency, and societal costs to improvement costs)

SELECTING SYSTEM IMPROVEMENTS

Minimum BCR RunsImplements All Potential Improvements With

BCR Above Minimum Target Level, use BCR=1.5 in C&P Report Scenario

Funding or Performance Constrained RunsRanks Potential Section Improvements by

BCRImplements Improvements with Highest

BCR’s Until Funding or Performance Target is Reached.

HERS OutputsProjected 2028 Pavement Ride Quality Indicators on Federal-Aid Highways Compared With 2008, for Different Possible Funding Levels

$45.0 $55.0 $65.0 $75.0 $85.0 $95.0 $105.0-25%

-20%

-15%

-10%

-5%

0%

5%

10%

Percent Change in Average Pavement Roughness (IRI)

Average Annual Investment Modeled in HERS (Billions of Dollars)

HERS OutputProjected 2028 Highway Operational Performance Indicators on Federal-Aid Highways Compared With 2008, for Different Possible Funding Levels

$45.0 $55.0 $65.0 $75.0 $85.0 $95.0 $105.0-2.0%

-1.0%

0.0%

1.0%

2.0%

3.0%

Percent Change in Average Speed

Average Annual Investment Modeled in HERS (Billions of Dollars)

Pe

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20

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HERS Output

$45.0 $55.0 $65.0 $75.0 $85.0 $95.0 $105.0-30%

-20%

-10%

0%

10%

20%

30% Total Delay

Congestion De-lay

Incident Delay

Average Annual Investment Modeled in HERS (Billions of Dollars)

Pe

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Projected Changes in 2028 Highway Travel Delay on Federal-Aid Highways Compared With 2008, for Different Possible Funding

Levels

Summary

HERS model allows for trade-off between improvements in infrastructure condition, safety and operational improvements using benefit cost analysis

HERS results can provide a benchmark against which to assess the performance targets under consideration

While HERS model is applicable for national level highway program, HERS-ST could be used for State level analysis

HERS is updated continually to incorporate new research findings and policy initiatives