Head restraint positions of drivers in Portland, Oregon
| Total | n | % | |
|---|---|---|---|
| No head restraint | 30 | ||
| Suboptimal position | 30 | 100 | |
| Fixed head restraint | 158 | ||
| Optimal position | 33 | 21 | |
| Suboptimal position | 125 | 79 | |
| Adjustable head restraint | 4099 | ||
| Optimal position | 280 | 7 | |
| Suboptimal position in horizontal dimension | |||
| Optimal vertical height | 1870 | 46 | |
| Suboptimal vertical height | 1949 | 48 | |
| Total observed head restraints | 4287 | ||
| Optimal position | 313 | 7 | |
| Suboptimal position | 3974 | 93 |