| Clue | Source | Date |
|---|---|---|
| Highway noise barriers | New York Times | 17 Dec 2017 |
| Road shoulders | Universal | 29 Aug 2017 |
| Highway shoulders | Wall Street Journal | 01 Jul 2017 |
| Highway noise barriers | ||
| Road shoulders | ||
| Road shoulders | Newsday | 07 Aug 2016 |
| Driver's shoulders | Newsday | 13 Feb 2016 |
| Banks of earth | ||
| Road shoulders | ||
| Road shoulders | ||
| Road shoulders | ||
| Canal banks | ||
| Earthen barriers | ||
| Earthen embankments | ||
| Banks of earth | ||
| Canal banks | ||
| Shoulders of roads | ||
| Road shoulders | ||
| Shoulders of roads. | ||
| Shoulders of paved roads. |