Smart Transport Emission Reductions

Last week I attended the NREL Energy Analysis Forum, where leading North American energy analysts discussed current thinking concerning greenhouse gas emission reduction strategies, much of which involves emission cap and trade programs (as summarized in the report by Resources for the Future, "Key Congressional Climate Change Legislation Compared"). Similarly, a recent report, "Reducing U.S. Greenhouse Gas Emissions: How Much At What Cost" evaluates emission reduction strategies according to their cost effectiveness.

Virtually all this analysis is biased against mobility management (strategies that increase transport system efficiency by improving accessibility options and applying more efficient incentives), for the following reasons:

* Co-benefits are ignored. Current analysis gives little consideration to benefits such congestion reduction, road and parking facility cost savings, consumer savings, reduced traffic accidents, and improved mobility for non-drivers, although these benefits are often larger in total value than emission reduction benefits. When all impacts are considered, mobility management strategies are often among the most cost effective GHG emission reduction strategies, because they are justified on economic grounds and so provide "free" environmental benefits.

* Current analysis generally ignores the additional external costs that result when increased vehicle fuel efficiency and subsidized alternative fuels stimulates additional vehicle travel, called a "rebound effect."

* Mobility management emission reductions are considered difficult to predict. Although case studies and models are available for many of these strategies, this information is not widely applied to energy planning.

* Mobility management programs are considered difficult to implement. Such programs often involve multiple stakeholders, such as regional and local governments, employers and developers, and various special interest groups. As a result, they tend to seem difficult and risky compared with other emission reduction strategies that only require changes to utility operations, fuel production or vehicle designs.

* Analysis often assumes that vehicle travel reductions harm consumers and the economy. In fact, many mobility management strategies benefit consumers directly and increase economic productivity. Our research, summarized in the report "Socially Optimal Transport Prices and Marekts" indicates that with more optimal pricing and planning practices, travelers would choose to drive less, use alternative modes more, and be better off overall as a result.


Described differently, there are two general approaches to reducing transportation emissions: reduce emission rates per vehicle-kilometer or reduce total vehicle-travel. The first often seems easier, but if done correctly, the second provides far more benefits and so is often best overall.

Currently proposed emission reduction programs (particularly those that rely on cap-and-trade) will not implement mobility management as much as optimal, and will miss an opportunity to help address other planning objectives, such as congestion reductions, crash reductions, consumer savings and improved mobility for non-drivers. It is up to people who understand the wider value of mobility management to educate energy analysts about these issues, so mobility management can receive the support justified.