Breaking the Carbon Emissions Cycle in the Transport Sector

Cracking the upward GHG emissions curve in the transport sector has proved exceedingly difficult. Research from Aalborg University in Denmark suggests that in some industrialized societies this may be changing.

2 minute read

June 27, 2014, 7:00 AM PDT

By patrickdriscoll


According to the International Energy Agency greenhouse gas emissions (GHG) from the transport sector have continued to rise in both the industrialized and industrializing countries, and are projected to continue to do so well into the 2030s and 2040s. One of the explanations for this is the strong network effects (path dependencies) associated with the system of car-based travel, where capacity expansions of the highway network induce further demand for higher automotive mobility. 

Recent research from Aalborg University in Denmark suggests that, at least in the case of the Copenhagen and Portland, Oregon metropolitan areas, the existing system of dependence on high-carbon modes of transport may be weakening. Changes in demography, fuel prices, behavior, residential location preference, and environmental concerns are all contributing to a reduction in vehicle miles traveled (VMT) across North America and Europe, thereby undermining the business case for new large-scale transportation infrastructure projects such as the proposed Ring 5 in Copenhagen and the Columbia River Crossing project in Portland.

The path dependencies embedded within large-scale transportation infrastructure projects have dramatically different carbon trajectories, depending on the mode. If cities and regions are to meet their aggressive carbon reduction goals, then they will have to, sooner rather than later, begin to shift their strategic investment focus away from high carbon, motorized forms of travel toward low- or no-carbon modes of travel. Such decisions may become increasingly easier to implement in light of the decaying political support and economics of massive expansions of the road network. 

Tuesday, June 24, 2014 in Planning Practice and Research

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Aerial view of town of Wailuku in Maui, Hawaii with mountains in background against cloudy sunset sky.

Maui's Vacation Rental Debate Turns Ugly

Verbal attacks, misinformation campaigns and fistfights plague a high-stakes debate to convert thousands of vacation rentals into long-term housing.

July 1, 2025 - Honolulu Civil Beat

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

July 9, 2025 - Diana Ionescu

Map of Haussmann's redesign of Paris in the 1850s through 1870s under Napoleon III.

In Urban Planning, AI Prompting Could be the New Design Thinking

Creativity has long been key to great urban design. What if we see AI as our new creative partner?

June 30, 2025 - Tom Sanchez

Red and white "Wildfire Evacuation Route" sign on signpost.

Cal Fire Chatbot Fails to Answer Basic Questions

An AI chatbot designed to provide information about wildfires can’t answer questions about evacuation orders, among other problems.

July 10 - The Markup

Protester at Echo Park Lake, Los Angeles holding sign that says "Housing is a human right"

What Happens if Trump Kills Section 8?

The Trump admin aims to slash federal rental aid by nearly half and shift distribution to states. Experts warn this could spike homelessness and destabilize communities nationwide.

July 10 - Shelterforce Magazine

Aerial of rainbow painted crosswalks at large intersection in Castro District, Sna Francisco, California.

Sean Duffy Targets Rainbow Crosswalks in Road Safety Efforts

Despite evidence that colorful crosswalks actually improve intersection safety — and the lack of almost any crosswalks at all on the nation’s most dangerous arterial roads — U.S. Transportation Secretary Duffy is calling on states to remove them.

July 10 - Streetsblog USA

Urban Design for Planners 1: Software Tools

This six-course series explores essential urban design concepts using open source software and equips planners with the tools they need to participate fully in the urban design process.

Planning for Universal Design

Learn the tools for implementing Universal Design in planning regulations.

Home and Land Services Coordinator

Appalachian Highlands Housing Partners

Associate/Senior Planner

Gallatin County Department of Planning & Community Development

Senior Planner

Heyer Gruel & Associates PA