Break-out Discussion Sessions
Briefing
- Preamble to Day 2 [PDF]
Presented by Alissa Kendall
Q1: Critique the Framework
- Goal (focus on scale and purpose)
- System boundary
- Functional unit
- Assumptions
- Recommended models and data sources
Discussion Summary of Question 1 [PDF]
Q3: Bitumen Feedstock
- How should we interpret bitumen feedstock (or feedstock energy in general)?
- Bitumen as a fuel:
- Do we consider the increased marginal emissions (CO2, heavy metals, etc.)?
- If so, how?
- Is the alternative life of upgrading important? If so, how should be included?
Discussion Summary of Question 3 [PDF]
Q5: Surface Characteristics and Rolling Resistance
- Do we have the right models?
- Can we have the information to adequately include the use phase?
- Beyond direct fuel use, where should the system boundary be drawn regarding vehicle operating effects?
- In the document, is the modeling approach outline adequate for consideration of traffic flow (i.e., congestion, acceleration, deceleration)?
Discussion Summary of Question 5 [PDF]
Q7: Multi-Criteria Decision-Making
- In making a decision, how do you consider both cost and environmental impact?
Discussion Summary of Question 7 [PDF]
Q8: Time Horizon
- The analysis period refers to the time horizon during which the inputs and outputs associated with the functional unit for a system or systems are inventoried. The initial construction of each system will have a different functional design life, and may be followed by a series of different maintenance and rehabilitation (M&R) activities to preserve its function. Properly assessing the pavement system over a time horizon presents a major challenge. Some proposed approaches to determine the analysis period include:
- Using 1.5 times the longest functional design life among all alternatives
- Using minimum next major rehabilitation activity
- Annualizing/amortizing construction events
Discussion Summary of Question 8 [PDF]
Q10: Recycling Allocation and Material: “Down-cycling”
- Pavement materials may be recycled on-site or through an off-site recycling system. In either case, allocating the burdens of recycled materials or repurposed to a specific pavement system is challenging. The following methods have been proposed in the LCA literature to address this challenge.
- One study considered allocation of recycled materials and assumed that each construction event is responsible for the materials it uses.
- A 50/50 method that allocates half the burden of producing and disposing of virgin materials to the first construction event and half to the final construction event, which uses recycled forms of the virgin material.
Discussion Summary of Question 10 [PDF]
Q11: Heat Island Effect
- The heat island effect is the result of a pavement’s albedo and emissivity properties:
- Impact is increased electricity consumption due to cooling demand and increased temperature for stormwater runoff
- How and when should the heat island effect be included within a pavement LCA?
- Are the current models adequate? Are they scalable to project-level analyses?
Discussion Summary of Question 11 [PDF]
Q14: What are the questions faced by policy-makers and what outcomes from LCA are necessary to answer these questions?
Discussion Summary of Question 14 [PDF]