Headrests to prevent whiplash
In rear-end collisions headrests are important for lessening the risk of neck injury, one of which is whiplash. Whiplash is the collective name for symptoms that result from a strong sudden backward movement of the head. During the last few years there has been an increase in the number of rear-end collisions. Together with the wider publicity about whiplash, this may be among the reasons for the many claims having been made to insurance companies.
In 1995-1996 there was a campaign for better use of the headrest to limit the consequences of rear-end collisions. In the EU, the
Number of rear-end collisions increasing
During the last few years, busier roads and higher speeds have caused a large increase in rear-end collisions. Rear-end collisions are collisions in which at least one car is hit from behind. The registration of rear-end collisions very much depends on the police registration and on whether occupants have put in a claim at their insurance company.
|
Year |
1989 |
1990 |
1991 |
1992 |
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
1999 |
2000 |
|
Number |
2242 |
2414 |
2393 |
2787 |
3051 |
3499 |
3910 |
3925 |
4138 |
4525 |
4636 |
4665 |
|
Share in total of rear-end collisions |
5.1 |
5.4 |
5.9 |
6.8 |
7.6 |
8.5 |
9.2 |
9.6 |
10.1 |
11 |
11 |
12.3 |
Development of the number of rear-end injury collisions 1989 - 2000 (source: AVV/BG).
Rear-end collisions have a large share of all collisions on rural roads, particularly those on the 100-120 km/hour roads.
However, the absolute number is highest on urban roads; it is three times higher than on rural roads. The number of casualties per kilometre travelled for female motorists is more than double that of male motorists.
The number of injury rear-end collisions has risen, but the number of Material Damage Only (MDO) collisions has not. That could indicate that it is not the actual number that is increasing, but the number registered by the police.
Number of whiplash crashes
Each year there are about 15,000 road crash casualties with whiplash, of which about 5,000 go to Accident & Emergency (A&E) departments of hospitals. In addition there are another 10,000 casualties with other neck complaints. These are probably partly the same sort of complaints as in real whiplash.
The numbers of whiplash casualties are a lot higher than the numbers of casualties in the previously mentioned crash data. This indicates:
- under-registration in police data;
- difficult identification of this type of crash casualty.
Headrest requirements: correct adjustment
Headrests are not compulsory in
In 1997, the EU agreed on a larger headrest height. However, because the Dutch are quite tall, the
Correct adjustment
The best protection is offered by:
- Correct vertical adjustment. If possible, the top of the headrest must be at the same height as the top of the head. The minimum height is just above the ears.
- Correct horizontal distance between head and headrest. This must be as small as possible; in any case less than
Headrest adjustment in practice
In 1995 many headrests were wrongly adjusted. This was the reason for a campaign between 1995 and 1997 to promote the correct use of headrests.
The campaign reached the target group (Mulder, 1997) and also affected their behaviour.
|
|
1995 |
1997 |
|
Drivers |
39% |
61% |
|
Front passengers |
61% |
74% |
Percentage of correct adjustment before and after the information campaign (Mulder, 1995; Goldenbeld, 1996).
However, in 1998 the situation was as bad as before the campaign; its effect was only short-lived.
The last study of headrests was carried out in 2000 (AVV, 2001).
|
Headrests that were too low |
||
|
|
1998 |
20001) |
|
Cars |
||
|
Drivers |
26% |
18% |
|
Front passengers |
13% |
10% |
|
Rear passengers |
- |
14% |
|
Delivery vans |
||
|
Drivers |
- |
14% |
|
Front passengers |
- |
10% |
|
1) Values corrected by SWOV. The values in the report have been corrected for the number of vehicles without headrests. |
||
Percentage of incorrectly adjusted headrests (Mulder, 1998; AVV, 2001).
In that year, the situation had slightly improved again.
Adjustment possibilities often insufficient
In 1995, 28% of those sitting in front had a horizontal distance larger than
91% of the new cars in this study had adjustable headrests, but in 9% of these the vertical lock did not work and for about 20% adjustment was difficult.
34% of the vertically adjustable headrests were also horizontally adjustable, but for half of these the adjustment didn't work properly. It was shown that motorists appreciate experts adjusting their headrests at the correct height. This offers good perspectives for information by importers and dealers.
References [SWOV reports in Dutch have a summary in English]
Bekkum, P.H.G. van, Wagemakers, J. & Hiddinga, S.K. (2001). Gebruik van beveiligingsmiddelen in 2000. Onderzoek naar het gebruik van autogordels, hoofdsteunen en andere beveiligingsmiddelen in personenauto's en bestelauto's. Ministerie van Verkeer en Waterstaat, Directoraat-Generaal Rijkswaterstaat, Adviesdienst Verkeer en Vervoer (AVV); Uitvoering Grontmij;.
Mulder, J.A.G. (1997). Gebruik van beveiligingsmiddelen in 1997. R-97-32. SWOV, Leidschendam.
Mulder, J.A.G. (1998). Gebruik van beveiligingsmiddelen in 1998. R-98-44. SWOV, Leidschendam.
Schoon, C.C., Coïni, M.J.L. & Burggraaf, D. (1995a). Hoofdsteunen en gordelhoogteverstellers; Resultaten van een veldmeting naar de mate van gebruik en de wijze van afstellen. R-95-19. SWOV, Leidschendam.
Schoon, C.C. (1995b). Technische aspecten omtrent aanwezigheid en gebruik van hoofdsteunen. Een studie uitgevoerd ten behoeve van de RAI Vereniging. R-95-30. SWOV, Leidschendam.