Bloody Weather Results

[bello]

Hey Everyone,

Right thanks to everyone that did the survey on motorcycles and weather a month ago, and as promised here are a few of the key findings of not only the survey but of the whole study.

In general motorcyclists were found to have two very different relationships with the weather:

1) Adverse weather presents a risk factor to ‘all-weather’ riders who tend to ride smaller engine motorcycles for commuting/work purposes and are more prevalent in urbanised areas. Adverse weather accidents occur most regularly in winter, frequently as a consequence of precipitation and surface ice reducing the road surface traction, leading to an increased chance of skidding.

2) The second relationship is the appeal of warm and dry weather drawing ‘fair-weather’ riders out onto the road who generally ride for leisure purposes on motorcycles with larger engine sizes in rural areas. Temperatures and thus accidents peak during summer as more motorcyclists are exposed to other risk factors. For Britain as a whole this latter relationship appears to dominate.

Obviously in real life the distinction between 'all-weather' and 'fair-weather' riders isn't so clear-cut but it helps to conceptualise them in this way to get an idea of how they have contrasting relationships with the weather.

Defective road surfaces likely a result of extreme temperatures appears to influence a fraction of accidents (0.6%). Interestingly a greater proportion of accidents where the road surface was defective occur in summer rather than winter. So the idea that in late winter and and early spring you have a loads of potholes which causes accidents during this period doesn't actually appear to be the case, it begs the question are there other road defects such as those caused by anomalously hot temperatures that cause an increase in summer.

There is a clear association between accidents where the road surface is wet with accidents where oil/diesel was present on the road surface. Of the 1003 motorcycles involved in an accident (between 2005-2009) where oil/diesel was present on the surface 49.6% of accidents occurred when the road was wet, seeing as during these 5 years only 23.5% of accidents occurred on wet roads, the percentage is significantly higher. As mentioned by a few of you in the survey this is likely a result of the rain raising the oil/diesel out of the cracks in the road where it has accumulated during dry periods.

Together daily maximum central England temperature and an England and Wales daily precipitation time series were able to explain 37.4% of variance in daily motorcycle accidents and even more so (49.9%) for just 126cc and over motorcycles (2000-2009).

The graph below shows that accidents involving larger bikes (126cc and over) (red line) have a yearly pattern which is very similar to the yearly pattern of maximum daily temperature (black line), both peaking in summer. Accidents for smaller bikes however (green and blue lines) tend to peak around early winter.


The table (attachment) below shows bikes skid more regularly in accidents than all other vehicle types, and understandably skid more often when the road surface is wet or icy.

From the survey:

Survey results showed that the type of adverse weather most likely to dissuade a motorcyclist from using their motorcycle was the risk of ice on the road surface, followed by snowfall or hail. High or Gusty winds took the next spot, and extreme temperatures and rainfall were very similarly ranked as the two least likely to have an influence. This agrees well with what motorcyclists thought were the biggest risk to them out on the road with ice on road surface ranked as the greatest risk 75% of the time, followed by snow or hail with 21%. Potholes appear to be the 3rd biggest risk regularly taking the 3rd spot. High or gusty winds take 4th and rain takes 5th.

Of the 93 respondents 23 (25%) had experienced an accident which they believed adverse weather was a leading cause of the accident, and 5 of 23 had experienced more than one weather related accident in their lives. Of these accidents 52% resulted from reduced road surface traction due to rainfall and 30% suggested ice covering the road surface was a leading cause.

Survey results reveal the perception of weather varies from motorcyclist to motorcyclist. Crucially 52% of respondents agreed or strongly agreed that the weather influences their decision to go for ride and 20% of riders seek alternative transport more than once a week, but on the other hand 26% of respondents would never seek alternative transport despite the weather being poor.

Ok so that turned out to be quite a lot of text, hope i haven't bored you too much

[Andy_Pagin]

Not sure what conclusions to draw from that lot, but lets hope it somehow helps play a part in improving safety.
____________________
They're coming to take me away, ho-ho, hee-hee, ha-haaa, hey-hey,
the men in white coats are coming to take me away.
Yamaha Vity -> YBR125 -> FZS600 Fazer -> FZ1-S Fazer

[keggyhander]

Someone seems to have forgotten that there's more horseshit on the roads in summer, and also more gravel falling out of wagons, because most construction work occurs in the summer.