We tried a dozen different models that used transportation and
density measures in an attempt to classify the active core, suburbs
and exurban areas. This chart
shows the summary results for other models that were tried.
We also tried to classify suburbs by using built form and urban morphology. This method did not give credible results for most cities. For some sample maps, see here.
For an explanation of why this built form method did not work well, please see this paper.
Statistics Canada also tried a classification based upon built form and distance from the Central Business District. See Martin Turcotte's article "The City/Suburb Contrast: How Can We Measure It ?"