Vehicle Classification for County Road Pavement Design
The State Aid Equivalent Single Axel Load calculator consists of a two tab Microsoft Excel spreadsheet. The first tab is for use with the recently updated heavy commercial traffic default values. The second tab is for use with site specific heavy commercial traffic percentages. Any spreadsheet cell that is “yellow” requires the user to input a reasonable value. Please have your Excel security setting set to low or click on enable macros for the program to run.
Below are updated percentage default values for the heavy commercial traffic using CSAH. The updated vehicle classification data contains 8 default values. These default values are based upon whether the road is rural or urban and the projected Annual Average Daily Traffic range. State Aid encourages counties to perform actual traffic counts whenever possible for the design of their pavements.
Rural/Urban CSAH Heavy Commercial Percentages
| Rural AADT Range | CAR |
2ASU |
3+ASU |
3ASEMI |
4ASEMI |
5+ASEMI |
TT/BUS |
TWINS |
Total |
Average HC PCT |
Range HC PCT |
| 1 - 300 | 86.72% |
4.71% |
2.24% |
0.35% |
0.71% |
3.81% |
1.45% |
0.01% |
100.00% |
13.3% |
9 - 38% |
| 301 - 750 | 86.56% |
3.44% |
2.17% |
0.39% |
0.69% |
5.32% |
1.40% |
0.03% |
100.00% |
13.4% |
4.7 - 34.3% |
| 751 - 1500 | 90.55% |
3.69% |
1.71% |
0.33% |
0.57% |
2.10% |
1.03% |
0.02% |
100.00% |
9.5% |
2.2 - 29.0% |
| 1500> | 91.39% |
2.32% |
1.24% |
0.16% |
0.32% |
3.33% |
1.23% |
0.01% |
100.00% |
8.6% |
2.1 - 19.1% |
| Urban AADT Range | CAR |
2ASU |
3+ASU |
3ASEMI |
4ASEMI |
5+ASEMI |
TT/BUS |
TWINS |
Total |
Average HC PCT |
Range HC PCT |
| 1 - 300 | 95.60% |
1.60% |
0.40% |
0.40% |
0.40% |
0.40% |
1.20% |
0.00% |
100.00% |
4.4% |
*N/A |
| 301 - 750 | 92.53% |
3.70% |
1.62% |
0.14% |
0.24% |
1.23% |
0.48% |
0.07% |
100.00% |
7.5% |
4.0 - 11.0% |
| 751 - 1500 | 94.72% |
2.14% |
0.98% |
0.19% |
0.30% |
0.94% |
0.71% |
0.02% |
100.00% |
5.3% |
1.1 - 10.6% |
| 1500> | 96.44% |
1.52% |
0.46% |
0.09% |
0.12% |
0.89% |
0.47% |
0.02% |
100.00% |
3.6% |
0.6 - 3.7% |
Note: Data from 2007 and 2008 County State Aid Study (Minnesota State University) and 1986 to 2002 vehicle class data (MnDOT). Urban is defined as the area within the boundaries of a city 5000 or more population and the Twin Cities metropolitan area.
*Data based on only one count, so there is no range.
For questions and information, please contact Bill Meinholz at william.meinholz@state.mn.us or 651-366-3832.