Comparison of Roads.
—In order to compare the relative merits of different types of roads weights are usually given to the different qualities entering into the roadway that they may be compared with a predetermined ideal. It must be remembered that such tables apply only to the particular road for which they are made out. No two can be exactly alike.
Here is one adapted from the author’s work on “Highway Engineering.”[184]
Comparative Table of Several Types of Roadway for Some Particular Locality
| Qualities | Ideal Road for this Particular Location | Best Earth Road | Sand Clay Road | Gravel Road | Mac- adam Road | Brick Road | Con- crete Road | Asphalt Block | Cre- osoted Wood Block | Bitu- minous Con- crete | Sheet Asphalt |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Low first cost | 20 | 20 | 16 | 16 | 15 | 10 | 12 | 10 | 8 | 14 | 13 |
| Low cost of maintenance | 20 | 15 | 15 | 10 | 8 | 9 | 8 | 8 | 10 | 8 | 10 |
| Ease of traction | 10 | 1 | 4 | 6 | 8 | 10 | 10 | 9 | 9 | 9 | 10 |
| Non-slipperiness | 10 | 9 | 9 | 9 | 9 | 8 | 5 | 5 | 5 | 5 | 5 |
| Noiselessness | 5 | 5 | 5 | 5 | 4 | 1 | 1 | 2 | 4 | 2 | 2 |
| Healthfulness | 10 | 5 | 5 | 6 | 8 | 9 | 9 | 9 | 8 | 9 | 9 |
| Freedom from dust and mud | 10 | 1 | 2 | 3 | 4 | 9 | 9 | 9 | 9 | 9 | 9 |
| Comfortable to use | 10 | 3 | 4 | 5 | 6 | 8 | 8 | 9 | 9 | 9 | 9 |
| Appearance | 5 | 2 | 3 | 3 | 4 | 3 | 4 | 5 | 5 | 5 | 5 |
| Total | 100 | 61 | 63 | 63 | 66 | 69 | 66 | 66 | 67 | 70 | 72 |
Tilson gives the following weights for city pavements having heavy traffic:[185]
| Pavement Qualities | Per- cent- age | Gran- ite Block | Wood Block | Brick | Sheet As- phalt | Bitu- lithic |
|---|---|---|---|---|---|---|
| Cheapness | 14 | 8 | 8 | 13 | 14 | 12 |
| Durability | 21 | 21 | 16 | 12 | 15 | 15 |
| Easiness of cleaning | 15 | 10 | 14 | 15 | 14 | 14 |
| Light resistance to traffic | 15 | 13 | 14 | 15 | 11 | 12 |
| Non-slipperiness | 7 | 7 | 4 | 6 | 5 | 6 |
| Ease of maintenance | 10 | 10 | 8 | 6 | 6 | 6 |
| Favorableness to travel | 5 | 2 | 5 | 3 | 4 | 4 |
| Sanitariness | 13 | 9 | 13 | 10 | 12 | 12 |
| Total | 100 | 80 | 82 | 80 | 81 | 81 |
| Less cheapness | 72 | 74 | 67 | 67 | 69 |
The Forest Service of the U. S. Department of Agriculture presents the following table:
| Pavement Qualities | Per- centage | Granite Block | Sheet Asphalt | Brick | Mac- adam | Wood Block | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Cheapness | 14 | 4 | 6 | 1⁄2 | 7 | 14 | 4 | 1⁄2 | |||
| Durability | 20 | 20 | 10 | 12 | 1⁄2 | 6 | 14 | ||||
| Ease of maintenance | 10 | 9 | 1⁄2 | 7 | 1⁄2 | 8 | 1⁄2 | 4 | 1⁄2 | 9 | 1⁄2 |
| Ease of cleaning | 14 | 10 | 14 | 12 | 1⁄2 | 6 | 14 | ||||
| Low resistance to traffic | 14 | 8 | 1⁄2 | 14 | 12 | 1⁄2 | 8 | 14 | |||
| Non-slipperiness | 7 | 5 | 1⁄2 | 3 | 1⁄2 | 5 | 1⁄2 | 6 | 1⁄2 | 4 | |
| Favorableness to travel | 4 | 2 | 1⁄2 | 4 | 3 | 3 | 3 | 1⁄2 | |||
| Acceptability | 4 | 2 | 3 | 1⁄2 | 2 | 1⁄2 | 2 | 1⁄2 | 4 | ||
| Sanitary qualities | 13 | 9 | 13 | 10 | 1⁄2 | 4 | 1⁄2 | 12 | 1⁄2 | ||
| 100 | 71 | 76 | 74 | 1⁄2 | 55 | 80 | |||||
Crosby gives three sets of ideal crusts for country roads: V for main roads, carrying a fairly heavy mixed traffic, W, secondary roads carrying moderate traffic, and X on minor roads with light farm travel almost wholly.[186]