[1] Joint Program in Transportation, University of Toronto, 35 St. George Street, Toronto, Ont. M5S 1A4, Canada
[2] Department of Civil Engineering, The University of Calgary, 2500 University Drive NW, Calgary, Alta. T2N 1N4, Canada
[3] Department of Civil Engineering, University of Toronto, 35 St. George Street, Toronto, Ont. M5S 1A4, Canada