Winter Maintenance and Cycleways

Increasing cycling as a means of personal travel could generate environmental benefits if associated with a corresponding decrease in car-based transport. In seeking to promote cycling in wintertime, it is desirable to understand how important the road surface condition is compared to other factors in people’s decision to cycle or not. In this thesis, the possibility of increasing the number of cyclists by improving the winter maintenance service level on cycleways is examined. The attitudes towards cycling during winter in general, and in relation to winter maintenance of cycleways in particular, is studied through questionnaire surveys. Bicycle measurements are related to weather data from Road Weather Information System, in order to know the influence on cycle flow during winter from different weather factors. Field studies are performed testing unconventional winter maintenance methods, in order to see if a higher service level could be achieved on cycleways and if that would lead to an increase in winter cycling frequency. The field studies are evaluated through road condition observations, measurements of friction, bicycle counts, a questionnaire survey and interviews. A visual method to assess winter road conditions on cycleways is developed, in order to compare the service levels achieved using different winter maintenance methods. There is a clear difference in mode choice between seasons. With improved winter maintenance service level it could be possible to increase the number of bicycle trips to work during winter with, at the most, 18 %, and decrease the number of car trips with 6 %. However, it could not be concluded with bicycle measurements, that an enhanced service level in fact, generated a higher winter cycling frequency. To increase cycling during winter, snow clearance is the most important maintenance measure. Skid control is not as significant for the choice of mode but is important to attend to for safety reasons. Winter road condition properties important both with regard to safety and accessibility of cyclists, are icy tracks formed when wet snow freezes, snow depths greater than about 3 cm of loose snow or slush, unevenness in a snow covered surface, loose grit on a bare surface. Weather factors with negative influence on winter cycling frequency, are temperatures below +5 °C, precipitation and strong winds. Only the occurrence of precipitation, not the amount of rain or snow, is significant for the cycle flow. Low temperatures are more important in reducing the cycle flow than precipitation. Temperatures around 0 °C seem to be extra critical for cyclists, probably due to the larger influence of precipitation and slippery road conditions at these temperatures. An unconventional method using a power broom for snow clearance and brine or prewetted salt for de-icing, provides a higher service level than winter maintenance methods traditionally used, but it is about 2 to 3 times more expensive. The method has great potential in regions, such as southern Sweden, with low snow accumulations but with major ice formation problems. To assess the maintenance service level, the visual assessment method developed and tested in this project is adequate for the purpose, however, further improvements are desirable. As a complement to the visual assessment, a Portable Friction Tester can be used to measure the surface friction on cycleways during wintertime.