## 4 Results  
### Analysis I: Comparison of Different Methods  
All the locations shown in Table 2 are asphalt concrete-surfaced pavements, and the n-factor was assumed to be 0.9 for all pavements. The frost penetration varies from 71 to 178 cm, Hamlin having the smallest, while Winnipeg had the highest frost penetration depth. Hamlin also showed the smallest Freezing Index among all the cities, while the highest FI was attributed to Viscount. As discussed earlier, the maximum penetration depth data were collected from the LTPP database, while the AMT and FI raw data were obtained through Environment Canada. As a result, it was challenging to find years in which complete yearly records could be retrieved on both platforms, in order to match and use them for research purposes. The years presented in Table 2 are, therefore, the ones that could yield the most complete data in both databases. The availability of satisfactory relevant data, therefore, should be mentioned as one of the existing hurdles to performing more comprehensive analysis in this area of research. Table 3 presents the pavement structures for each site, subgrade soil description, and soil classification, according to the Unified Soil Classification System (USCS). The complete dataset used for frost depth calculation for St. Celestin site can be found in Boutonnet and St-Laurent, 2003 [15], and hence is not repeated in the current paper. Figure 4 compares the frost depths obtained from field data with those predicted using the MTO, MTQ, and TCCA methods. The subgrade soil classification is indicated under each city's name in this bar chart. The difference between the predicted frost depths from each method and those measured from the field data is shown above each bar in percentage, indicating the accuracy of these models in predicting the frost depth for different regions and soil types. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**ID** & **Year** & **Soil Description** & **Closest City** & **Frost Depth** & **AMT** & **FI** \\
27.6251 & 02/03 & Poorly Graded Sand with Silt & **Demoldij, MN** & 178 & 4.58 & 1339 \\
30.0114 & 03/04 & Poorly Graded Sand with Silt & Great Falls, MT & 76 & 8.25 & 486 \\
36.0801 & 03/04 & Silty Sand & Hamlin, NY & 71 & 4.25 & 1170 \\
38.1801 & 02/03 & Silty Sand & Varden, MB & 178 & 9.08 & 461 \\
390.6405 & 95/96 & Fat Inorganic Clay & Viscount, SK & 177 & 2.75 & 1607 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Summary of recorded field data for the selected sites in this study. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Closest City** & **Pavement Structure: Material (Thickness in cm)** & **Soil Type** & **Soil Class** \\ \hline Winnipeg, MB & AC (15.24) Concrete (24.89) Granular (12.446) & Fat Inorganic Clay (CH) & CH \\  & & Granular (14.986) & \\ Beatrice, ON & AC (14.48) AC (11.68) Granular (17.02) Granular & Sandy Silt (ML) & ML \\  & & (66.80) & \\ St. Celestin, QC & AC (18) Granular (30) Granular (42) & Silty Clay (CL) & CL \\ New Haven, VT & AC (7.62) AC (13.97) Granular (65.53) & Poorly Graded Gravel with Silt and \\  & & Sand (GM) & GM \\ Bemidji, MN & AC (8.64) AC (14.73) Granular (25.91) & Poorly Graded Sand with Silt (SP) & SP \\ Great Falls, MT & AC (19.05) Granular (31.50) & Poorly Graded Sand with Silt (SP) & \\ Hamlin, NY & AC (3.05) AC (9.65) Granular (21.34) & Silty Sand (SM) & \\ Varden, MB & AC (11.18) Granular (14.22) granular (33.53) & Silty Sand (SM) & SM \\ Viscount, SK & AC (15.49) Granular (22.86) Sand Asphal (6.35) & Silty Sand (SM) & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Pavement structures and subgrade soil classification per USCS. Looking at the fine-grained soils, the results indicate that the MTO method overestimated the frost depth penetration by 18% for the fat clay (CH) soil type, while it resulted in about 6% and 10% underestimation in the sandy silt (ML) and silty clay (CL) cases, respectively.