Consideration was also made of the weight of the useful load as separate from the weight of the vehicle itself. Animals not harnessed were considered as a part of the useful load.
In Italy traffic censuses followed practically the same classification and methods as in France.
In the United States some of the states have used coefficients of reduction, or importance factors, while many others have contented themselves with a count of vehicles only.
In 1910 Maryland used the following:
| 1. | Ridden horse and one-horse vehicle | 2 |
| 2. | Two-horse vehicles | 4 |
| 3. | Three-horse vehicles | 6 |
| 4. | Four-horse vehicles | 8 |
| 5. | More than four-horse vehicles | 12 |
| 6. | Motor cycles | 2 |
| 7. | Motor runabouts | 10 |
| 8. | Four- or five-seat touring cars | 20 |
| 9. | Six- or seven-seat touring cars | 40 |
| 10. | Motor trucks or drays | 20 |
The New York State Highway Department took a census in 1909 in which the following classification and reduction coefficients were used:
| Class of Traffic | Relative Weight |
|---|---|
| Horse-drawn traffic | |
| Horses with vehicles | 1 |
| One-horse vehicle, light | 2 |
| One-horse vehicle, heavy | 3 |
| Two-horse vehicle, light | 3 |
| Two-horse vehicle, heavy | 4 |
| Three-horse vehicle, heavy | 5 |
| Four-horse vehicle, heavy | 6 |
| Motor vehicles | |
| Motor cycles | 1 |
| Two-passenger cars | 2 |
| Three-passenger cars | 3 |
| Four-passenger cars | 4 |
| Five-passenger cars | 6 |
| Seven-passenger cars | 7 |
| Trucks, omnibuses, etc. | 10 |
| Miscellaneous | |
| Traction engines | 15 |
| Two traction engines | 30 |
| Miscellaneous heavy traffic | 5 upward |
The Massachusetts Highway Commission, 1912 Report, say, “After all it is not numbers which tell the story, it is weight, and it is not weight alone, but the vehicle by which it is transported, whether by horses or by motor.... All these considerations are probably not so important on many road surfaces as the actual weight imposed upon the road per inch width of tire resting upon the road.” There was used in this census the following weights:
| Motors | Tons |
|---|---|
| Runabouts | 1.43 |
| Touring cars | 2.23 |
| Trucks | 6.25 |
| Horse-drawn vehicles | |
| One-horse, light | .36 |
| One-horse, heavy | 1.12 |
| Two or more horses, light | .54 |
| Two or more horses, heavy | 2.46 |
James and Reeves, with the United States Bureau of Public Roads, recommend the ton-mile basis and give the following weights: