JOHN S. ALLEN'S BICYCLE FACILITIES, LAWS AND PROGRAMS PAGES
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Auch auf deutsch erhältlich!
This page is a translation of the page (in German) "(Un)Sicherheit auf Radwegen" by Bernd Sluka.
Translation by John S. Allen, March 22, 2002, updated September 30, 2006 and March 3, 2007.
The opinion that "sidepaths are safe" is common -- so common that hardly anyone questions it any more. It is, rather, taken as an assumption. But there is a large number of studies which have overturned this dogma.
The Federal Traffic Institute (Bundesanstalt für Straßenwesen) has offered a publication on this topic. The report on Research Project 8592, Safeguarding of Bicyclists at Urban Intersections (Sicherung von Radfahrern an städtischen Knotenpunkten) includes research into "good" bikeways along heavily-used urban arterial streets. Specific, known problem cases are examined, such as sidepaths on the left, two-way sidepaths and sidepaths on which pedestrians are also permitted; however, the study only considers sidepaths which meet minimal standards for width, configuration and sight lines. Nonetheless, the results are uniform: the risk of crashes at intersections is multilplied by sidepaths -- for example, by about five times at intersections without traffic signals. Extensive physical modifications (raising the crossing) increase safety -- the sidepaths are then "only" twice as dangerous as riding a bicycle in the street.
Another report, Traffic-safe Design and Configuration of Bikeways (Verkehrssichere Anlage und Gestaltung von Radwegen) primarily addresses crashes that occur between intersections. There, too, sidepaths prove, on average, not to reduce the number of crashes. The best result that can be shown is an equal crash rate, with a shift to other types of crashes. In particular, crashes between bicyclists and stopped vehicles dominate when riding on the roadway; these are considerably less common with greater spacing from parked vehicles. The simple measure of recommending that bicyclists maintain spacing to their right would make riding on the roadway even more distinctly safe.
In summary, it may be stated that urban sidepaths increase the risk of crashes significantly, even along streets where they are regarded as "necessary" because of high traffic volume. This conclusion holds true, in particular, even for "high-quality" sidepaths which conform to design guidelines. Design which conforms to standards therefore does not succeed in producing a "safe sidepath". Additional risks such as bicycle traffic on the left side, crossing the street to reach the sidepath, pedestrians on sidepaths or simply the widespread poor quality of construction only increase this risk.
I have prepared graphics to illustrate some of the conclusions of these two reports, and additional material on the topic of bicycling safety. These graphics are especially suitable for use as presentation slides.
I could, for example, cite the result of research in Denmark (Bach/Rosbach/Jørgensen), which was cited in a study published by the German Minister of Transportation. It is a before-and-after comparison of urban one-way sidepaths -- 105 segments with a total length of 64 km, over a period of 3 years -- and not even the especially hazardous two-way sidepaths, on which some bicyclists ride facing the motor traffic in the adjacent lane. Bicycle traffic volume did not increase during the study period.
|Crashes||between junctions||at junctions|
|All bicycle crashes||46||49||71||105|
|All motor vehicle||108||108||169||213|
|Motor vehicle/motor vehicle||28||34||53||66|
|Before; no sidepaths
After: with sidepaths
|Evaluation (from the research):
Then there are the conclusions reached by the Berlin police in 1986 that nearly half of the bicycle crashes occur on streets with sidepaths. These are, however, only 18% of all streets. On streets with sidepaths, the crashes also were more serious. If the traffic counts by the municipal senate are applied to the crash rates, it can be established that the risk is about three times as great on sidepaths -- though this is not a perfect comparison: bicycles travel more slowly on sidepaths, and the risk is measured per unit of time -- so the risk per distance traveled is greater than this comparison shows. Nonetheless, it shows that the crash risk on sidepaths is three times as great.
From 1981 through 1985, the number of crashes on sidepath segments in Berlin increased by 114%, but it decreased by 9% on other streets. The length of sidepaths increased by only 20% during this period, and the number of bicyclists hardly increased at all.
Thereafter, the counting of bicycle crashes in Berlin was discontinued. [Bernd Sluka's explanation of how and why it was discontinued, in response to the translator's inquiry] Nonetheless, there are additional, similar results from Berlin. For example, the newsletter of the Berlin chapter of the German Federation ADFC, Radzeit, has indicated that 75% of serious and fatal bicycle crashes occur on sidepaths, although only 10% of the streets in Berlin have sidepaths.
Similar results have been obtained (though I have not reviewed them) in Munich, Hannover and Braunschweig.
Let us compare, for example, Göttingen and Osnabrück Both cities are approximately the same size. Osnabrück has approximately three times the length of sidepaths.There is less bicycle traffic in Osnabrück. Relative to the number of bicycle trips, Osnabrück has more than three times as many bicycle crashes as Göttingen.
Also, most bicycle crash victims are elderly people and children. It is precisely they who are more seriously endangered by the complexity of sidepaths, on the one hand, and the false sense of security they provide, on the other.
Most of the studies listed above discuss urban sidepaths along streets. There is almost no research into sidepaths outside urban areas. There are, however, indications of an increase in danger there as well. For example, it can be calculated from the numbers in the research report Unfälle mit Radfahrern in Bayern (Bicycle Accidents in Bavaria) that there are three times as many bicycle crashes per kilometer of non-urban Bavarian roads with sidepaths, as on non-urban roads without sidepaths. If additional results (for example, from , ) are factored in, which show that the number of bicycle crashes is generally independent of the volume of bicycle traffic, then the indication is that there is approximately three times the risk on non-urban roads with sidepaths.
1999-01-19 (© Bernd Sluka); most recently revised 2006-08-28
This text may be freely copied, linked and distributed, as long as the citation is complete, unchanged and includes author contact information.
Translation is by the author's permission.
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