Analyzing Changes to Truck Size and Weight Regulations

Methods for States

presented to

AASHTO Subcommittee on Highway Transport

presented byDonald Ludlow, Cambridge Systematics

June 28, 2011

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How to analyze TSW proposals

Weaknesses of past studies: TRB Special Report 267

» The methods used in past studies have not produced satisfactory estimates of the effect of changes in truck weights on bridge costs.

» It is not possible to predict the outcomes of regulatory changes with high confidence.

» It is essential to examine the safety consequences of size and weight regulation. Research and Monitoring needed to understand the relationship of truck characteristics and truck regulations to safety and other highway costs are not being conducted today.

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How to analyze TSW proposals: AASHTO Evaluation Criteria

Safety—Will the proposal improve safety on the interstate?

Economic Benefit—Will the proposal produce a positive economic outcome?

Infrastructure preservation, renewal, and capacity—Will the proposal adversely affect the condition and/or the performance of highway infrastructure?

Congestion reduction—Will the proposal reduce highway congestion?

Modal diversion—Will the proposal cause a shift of traffic to highway from rail or waterways that will have adverse impacts on infrastructure, safety or the environment?

Financing assurance—Will the proposal provide guaranteed funding to equal the costs of necessary infrastructure improvements and increased enforcement?

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VMT Shift*

VMT Pre-test / Post-test» How many trucks before the

change?» How many trucks after the

change?

VMT shift by type of truck» FHWA Classifications» State-specific configurations» Develop controlling assumptions

– Shipper / carrier outreach– Commodity / economic analysis

VMT shift by functional classification» Shift from local to Interstate» Develop controlling assumptions

– Shipper / carrier outreach

Tools / Data» Vehicle Travel Information

System (VTRIS)» Vehicle classification counts

(state)» WIM

*Method applies to “pioneering” statesIn the future, we may have REAL observations from which we can derive more accurate factors

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How to analyze TSW proposals: AASHTO Evaluation Criteria

Safety—Will the proposal improve safety on the interstate?

Economic Benefit—Will the proposal produce a positive economic outcome?

Infrastructure preservation, renewal, and capacity—Will the proposal adversely affect the condition and/or the performance of highway infrastructure?

Congestion reduction—Will the proposal reduce highway congestion?

Modal diversion—Will the proposal cause a shift of traffic to highway from rail or waterways that will have adverse impacts on infrastructure, safety or the environment?

Financing assurance—Will the proposal provide guaranteed funding to equal the costs of necessary infrastructure improvements and increased enforcement?

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How to analyze TSW proposals: Safety

Are the heavier trucks safe to operate?» Driver training» Equipment certification» Vehicle dynamics

What is the accident rate by truck?» By functional classification» From research» From observation

Apply shifts in VMT by truck configuration against crash rates

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How to analyze TSW proposals: Infrastructure preservation, renewal, capacity

Bridges» Test bridges for strength – will the bridges

accommodate the heavier trucks?» Test bridges for fatigue – how will the trucks affect

bridge life (structure and deck)» How do results affect life cycle costs?

Pavements» Test pavements for fatigue (e.g. DARWIN ME)» How do results affect life cycle costs?

Capacity / Congestion» Analyze VMT shift using state travel demand models» Use HERS-ST (passenger car equivalents) for urban

areas if there is no model available

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How to analyze TSW proposals: Modal Diversion

Rail-to-truck diversion» Will loads shift from rail to truck?» Which commodities are vulnerable?» What other factors influence the shift?

Conduct outreach» Shipper interviews» Railroad outreach

Conduct data analysis» Develop controlling assumptions

– Commodities– Distances– Origin-destination pairs– Ton-mile costs

» Estimate candidate loads

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How to analyze TSW proposals: Financing AssuranceWill the proposal provide guaranteed funding to equal the costs of

necessary infrastructure improvements and increased enforcement?

Estimate costs (or savings) of infrastructure improvements

Estimate costs of increased enforcement

Estimate costs of increased permit administration

Estimate increased permit revenue

Other costs / savings

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How to analyze TSW proposalsRoute Selection—Routes suitable for increased size and/or weight on the interstate will be determined by the state based on the evaluation criteria above and the conditions below.

Infrastructure Assessment—No interstate route (including access) will be approved for increased size and weight before an assessment determines that it can be done without serious adverse impacts on highway infrastructure (including access) or before necessary improvements are made.

Cost Estimate—A cost estimate must be carried out to determine the total cost and timing of investments made necessary by the change in truck size and weight.

Safety Requirements—Vehicles operating under the increased size and weight limits will be required to be of the highest available quality, including all of the standard safety technology; drivers will be required to have outstanding safety records; and the companies will be required to have strong safety histories.

Monitoring and reporting—A rigorous monitoring system must be established to produce regular reports to determine whether the outcome of the change in federal truck size and weight limits on the interstate are consistent with the evaluation criteria.

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How to analyze TSW proposals (con’t)Monitoring and reporting—A rigorous monitoring system must be established to produce regular reports to determine whether the outcome of the change in federal truck size and weight limits on the interstate are consistent with the evaluation criteria.

Infrastructure funding—A mechanism must be in place that will guarantee that the cost of any improvements determined to be necessary by the Infrastructure Assessment will be met by revenues from the benefiting carriers and shippers.

Implementation funding—The federal government must provide the funds necessary for enforcement, monitoring and administration necessary for the state DOTs to implement the changes in truck size and weight on the Interstate system.

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Questions and Discussion

Thank You!