The influence of wire rope barriers on motorcyclists

University essay from Luleå/Civil and Environmental Engineering

Abstract: The implementation of wire rope barriers on 2+1 roads has significantly
improved road safety performance on the Swedish road network. The main
purpose of wire rope barriers is to prevent oncoming traffic from head-on
collisions by redirecting errant vehicles back onto the carriageway in a
controlled manner causing, at most, damage to the vehicle. However,
motorcyclists have raised concerns that wire rope barriers pose more danger
to them than any other crash barriers. There is not though sufficient
accident data and scientific knowledge to support this concern. Nonetheless,
it is necessary to determine what influence this type of barrier has on the
motorcyclist, especially with the increasing implementation of wire rope
barriers and the growth in motorcycle traffic year on year. This is the
objective of this study.

The first part of this study introduces general motorcycle safety. Then
information on wire rope barriers and their implementation in the rural road
network in Sweden is provided. Further on, the study attempts to assess the
safety of roads with wire rope barriers with respect to motorcyclists based
on accidents contained in the accident data. The main part of this study
concerns an assessment of the influence of wire rope barriers on
motorcycles, in particular how they affect their speed, performance and
choice of travel routes. These were measured by means of traffic volume and
speed data analysis, interviews and questionnaires and site study
measurements. Finally, future actions that ought to be taken are proposed at
the end of the study.

The accident analysis showed that wire rope barrier roads were substantially
less safe for motorcycles than they were for any other road users. Moreover,
the majority of interviewed motorcyclists were critical of the barriers and
felt insecure when riding along them. The results showed that despite their
concerns motorcyclists did not tend to avoid roads with wire rope barriers.
In terms of speed performance the results were unclear. On one hand there
seems to be evidence that road barriers influence the speed at which
motorcyclists travel. The site study and statistical data showed that on
roads with wire rope barriers motorcycle speeds were rather concentrated
around the speed limit. In addition on equivalent roads without barriers
motorcycle speeds were rather spread out and in many cases either
substantially exceeded the speed limit or were much below it. On the other
hand, nearly three quarters of interviewed motorcyclists stated that
barriers had no influence on their speed.

In conclusion, this study showed that wire rope barriers could be perceived
as a safety issue for motorcyclists. However, this has to be set against the
fact that there is not sufficient statistical information available on
motorcyclists in any of the areas analysed. Furthermore, there has been no
in-depth study of wire rope barrier safety with respect to motorcyclists.
Motorcycles are also not included in approval tests of wire rope barriers
(or any other crash barriers). Growing motorcycle traffic and barrier
implementation and the feeling of insecurity of riders are all factors that
significantly justify more research to be carried out in this area.