Abstract

Sustainable product design has been considered as one of the most important practices for achieving sustainability. To improve the environmental performances of a product through product design, however, a firm often needs to deal with some difficult technical trade-offs between traditional and environmental attributes which require new design concepts and engineering specifications. In this paper, we propose a novel use of the two-stage network Data Envelopment Analysis (DEA) to evaluate sustainable product design performances. We conceptualize ‘‘design efficiency’’ as a key measurement of design performance in terms of how well multiple product specifications and attributes are combined in a product design that leads to lower environmental impacts or better environmental performances. A two-stage network DEA model is developed for sustainable design performance evaluation with an ‘‘industrial design module’’ and a ‘‘bio design module.’’ To demonstrate the applications of our DEA-based methodology, we use data of key engineering specifications, product attributes, and emissions performances in the vehicle emissions testing database published by the US EPA to evaluate the sustainable design performances of different automobile manufacturers. Our test results show that sustainable design does not need to mean compromise between traditional and environmental attributes. Through addressing the interrelatedness of subsystems in product design, a firm can find the most efficient way to combine product specifications and attributes which leads to lower environmental impacts or better environmental performances. This paper contributes to the existing literature by developing a new research framework for evaluating sustainable design performances as well as by proposing an innovative application of the two-stage network DEA for finding the most eco-efficient way to achieve better environmental performances through product design.

Introduction

In December 2007, the European Commission proposed the introduction of legally-binding fuel efficiency standards for new cars. The proposed law says that CO2 limits should be differentiated according to the type of car and that the so-called ‘‘utility parameter’’ used to define the targets should be the car’s weight. In simple terms the proposal says heavier cars should get easier (higher) CO2 standards and lighter cars should get tougher (lower) ones (European Federation for Transport and Environment, 2008). Similarly, the US Environmental Protection Agency (EPA) and the Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) are finalizing a set of fleet-wide average CO2 emission standards where each vehicle has a different CO2 emissions compliance target depending on its ‘‘footprint value’’ related to the size of the vehicle (US EPA, 2010).