| Value | Category | Cases | |
|---|---|---|---|
| 1 | Tar/Tarmac (Paved) | 44 | 
                                    
                                    12.8%
                                 | 
| 2 | Gravel | 87 | 
                                    
                                    25.4%
                                 | 
| 3 | Dust | 205 | 
                                    
                                    59.8%
                                 | 
| 96 | Other | 7 | 
                                    
                                    2%
                                 |