1. Departments of Mechanical Engineering and Engineering and Public Policy, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
2. Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309, USA.
3. Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
4. Department of Engineering and public Policy, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
5. Department of Civil Engineering, University of Connecticut, Storrs, CT 06269, USA.
6. IFU-Fraunhöfer Institüt, Garmisch-Partenkirchen, Germany
7. California Air Resources Board, Sacramento, CA 95814, USA.