A life cycle assessment framework for complete streets

“Complete streets” is a design concept for streets and intersections (existing and/or new) intended to encourage active transportation users (bicyclists, pedestrians) and vehicles, by making the streets safer and more... [ view full abstract ]

“Complete streets” is a design concept for streets and intersections (existing and/or new) intended to encourage active transportation users (bicyclists, pedestrians) and vehicles, by making the streets safer and more convenient and attractive for active transportation. They are designed for the communities use regardless of age, ethnicity, ability or income. This concept is expected to bring mode choice changes in the community from motorized transportation to active transportation. Complete streets are being advocated for urban areas and offer the potential for environmental, public health and economic benefits. Complete street design responds to its community context which makes it unique for every project, i.e. complete street design for a less populated area might be very different from that of a populated area however, ensuring safety, livability and convenience for everyone. The quantitative analyses of the potential benefits that can be achieved from such conceptual design are lacking. A review of existing literature shows that no life cycle assessment (LCA) has been conducted for any complete street project. Moreover, there is a lack of socio-economic impact indicators in LCAs for transportation projects.

As funding for complete streets projects is becoming much more widely available, the development of project evaluation metrics that consider quantitative socio-economic impacts when assessing, prioritizing and improving projects has increasing importance.  Performance metrics are also needed for evaluation of social equity of project selection, which is a critical issue for complete streets. To address these gaps, this project develops a framework for LCA of complete streets projects, including the development of socio-economic impact indicators, and then tests it using several case studies.  A consequential approach is used where the physical, economic and social processes that go into a system are modelled and changes in the behavior of the system will be quantified.  Critical questions considered in the framework are how complete streets change mode choice within trips, and what are different social goals (economic, health, safety, etc) that should be considered?  The results are also intended to point out gaps in knowledge and data, and point towards a road-map for future development of the complete streets LCA guidelines and tools. The potential case studies will be selected from the following design scenarios identified by National Association of City Transportation Officials;

• Downtown two way street
• Downtown thoroughfare
• Boulevard
• Neighborhood main street
• Neighborhood street

This project lays the foundation for the creation of guidelines for social and environmental LCAs for complete streets. Combined with life cycle cost analysis it will produce a complete, transparent and quantitative picture of a complete street project within contexts and goals of the region, neighborhood, corridor and street. This project is funded through the National Center for Sustainable Transportation at the University of California Davis with funds provided by the California Department of Transportation. The project is in its initial stages.