Off-Road Impacts of Mountain Bikes


This summary presents the main points raised from this review of current research "state-of-knowledge" about the impacts of mountain bikes. The key areas reviewed are the physical impacts of recreational use of tracks, the social conflicts between different track users and the recreation experience preferences of mountain bike riders. However, mountain biking is a recent development, and to date there has been little research done on its physical or social implications.

5.1 Physical Impacts of Recreational Use

The greatest proportion of trampling impact on previously undisturbed surfaces is represented by the initial damage and removal of vegetation, and the formation of unplanned bare earth trails. This represents an uncontrolled version of the basic process undertaken by managers when they develop a formed track. When a track is developed by managers, most of the environmental impacts are incorporated into this process. Once the track is established, it becomes the focus of visitor use, and effectively confines further use impacts to the controlled setting it provides. However, whether they are created formally or informally, four main types of track problems can arise from continued recreational use:

· Excessive erosion.

· Muddiness (with or without lateral spread).

· Multiple parallel trails.

· Development of impromptu trails at attraction sites.

While research into possible relationships between recreational use and problems like these has been extensive, almost none has addressed the specific impacts of mountain bikes.

In general, apart from anecdotal observations on mountain biking impacts, managers have had to rely upon the findings of the predominantly soil-science based research into recreational trampling by hikers and horses, and the effects of motorised vehicles.

In general terms, the overall findings of research related to physical impacts of recreational use of trails emphasised:

· The primary importance of rainfall intensity and slope gradient as key factors in explaining soil loss on trails.

· That soil properties such as structure, texture and moisture content determine the resistance to erosion, and play secondary roles.

· That trail degradation occurred regardless of specific uses, and that this was more dependent upon geomorphic processes than the types and amounts of activity.

5.2 Physical Impacts of Mountain Bikes

5.2.1 Physical Impacts of Wheels

While the physical impacts of mountain bikes are often associated with those of motorised vehicles through the common feature of having wheels, they are non-motorised vehicles, and lack the weight and torque-generating capacity which contribute to the often extreme impacts from motorised vehicles such as motorbikes. However, the key physical impact distinction between mountain biking and other non-motorised trail activities does lie in the unique effects of wheels on surfaces, relative to those arising from trampling by feet. The development of ruts, mainly from skidding from braking on downhill slopes, can promote erosive water-flows to a greater extent than by foot-step puddling, and is the most distinctly unique mountain-bike impact. Similar gouging can also be caused on uphills, especially by over-powered wheels more characteristic of motor-driven wheels then pedal-driven.

5.2.2 Comparison of Mountain bike and other activity impacts

Research to date has indicated that the degree of impacts from mountain bikes, relative to those of walkers who have their own unique forms of impacts, appear to be similar. The general consensus drawn from studies comparing activity impacts was that trampling impact was greater on slopes than on level sites; on wet rather than dry surfaces; and that it tended to be greatest for hikers and horses moving downslope, and motorbikes moving upslope. Mountain bikes were not included in these comparisons, but like motorbikes they would tend to roll downhill except when over-braking, and lacking the power to the wheels, generate far fewer gouging impacts from wheel-spin on uphills.

It has not been established in the research done to date, that mountain bikes have greater overall impact on tracks than do walkers. However, it is obvious that mountain bikes do have some different types of impacts. The research to date indicates that it would not be appropriate to state that one is any "worse" than the other. It would appear that the main physical impact implication from the advent of mountain biking really lies in the increase in user numbers they may represent, rather than in the nature of the new activity in itself. More research on the issue of comparative effects between activities is generally required.

In the types of impacts noted above, research has consistently indicated that the location of the track and condition of its construction through susceptible areas was more important in the occurance of impacts than the type of activity present.

5.3 Social Impacts of Mountain Biking

Recreation conflict is a more complex phenomena than simply a case of "one activity versus another". There are a number of reasons which are usually given for disapproving of mountain bikes in off-road (track) settings. From consideration of all the studies and references available, these subjective reasons can generally be summarised as:

· Perceptions of greater environmental impacts and damage from mountain biking.

· Safety hazards of fast and silent mountain bikes.

· Attitudes that mountain biking is an inappropriate activity in the environment.

· Perceptions that mountain bikes encroach upon walking opportunities.

· Perceptions that mountain bikers are less interested in the setting and environment.

· A general dislike of mountain bikes and what they are perceived to represent.

In summary, these reasons can categorised as:

· Perceptions of environmental impacts.

· Perceptions of safety hazards.

· Perceptions that mountain biking is "inappropriate".

5.3.1 Perceptions of Environmental Impact

A perception that mountain bikes have more impacts on the environment (e.g., tracks) than do other uses (e.g., walking), is common to most statements about conflicts. But despite this general perception, the research evidence to date has not provided confirmation of greater impact. What little research is available appears to suggest that mountain bikes do not cause disproportionately greater impacts to tracks than walkers.

However, the impacts that mountain bikes do have are distinctive (e.g., tyre tracks), and this obvious difference may play a significant role in how the overall effects of mountain bikes are perceived.

5.3.2 Perceptions of Safety Hazard

A perception that mountain bikes present a safety hazard to other users is as equally common as are the perceptions that they cause greater environmental impacts. The types of hazards posed can be summarised as:

· Cyclists may ride too fast for conditions (e.g., on crowded, multiple-use trails).

· Cyclists may not slow and/or be prepared to stop when approaching blind corners.

· Cyclists may surprise hikers and horses on trails as they move quietly and fast.

These concerns are valid, and it is apparent that the behaviour of some riders has posed a hazard. While potential hazards do exist from irresponsible riding, cases of actual accidents or injuries are rarely reported.

As with environmental impacts, there is insufficient research to draw solid conclusions about the real and perceived hazards posed by mountain bikes, and the effects of these on the experiences of other users. What does seem clear is that some walkers will feel uncomfortable knowing that mountain bikes may be present, whether a real hazard exists or not.

Some research suggests that with more familiarity of mountain bike encounters, hazard concerns may diminish, but to date this research is inconclusive. And as with perceptions of environmental impacts, the degree to which perceptions of safety hazard actually relate to disapproval of mountain bikes on principle, is unclear.

5.3.3 Perceptions that Mountain Biking is Inappropriate Environmental impact and safety hazard perceptions are the two most common reasons given for recreation conflict perceptions with mountain biking. However, it is apparent that these cannot be easily distinguished from more complex perceptions that mountain biking is "wrong", and "should not be allowed" in off-road settings.

This third type of conflict perception is based upon assumptions by walkers (and also often managers), that the personal characteristics, motivations, behaviour types, environmental attitudes, and activity-styles of mountain bikers are fundamentally different from their own. In this respect, conflict between walkers and mountain bikes represents other inter-activity conflicts already widely documented in crowding and conflict research.

The types of comments generally made about mountain bikes, indicates that for many walkers (and managers), mountain bikes fall into the category of motorised off-road vehicles. The impact perceptions associated motorised activities have also emphasised environmental impact and safety; the appearance, noise, behaviour, presence of mechanisation; and the inappropriateness of such in natural settings. Implicit here has been the assumption that the recreation objectives, environmental attitudes, and values of these other users are also different.

In general, research has found clear differences between motorised and non-motorised users in the recreation experiences they are seeking. However, while the research comparing mountain bike riders and walkers has not been extensive, the findings to date suggest that the two groups are more similar than is generally perceived. In this context, it would appear that continued association of mountain biking with the "motorised" activity groups would be misleading.

To highlight the complexities of conflict perceptions, it is useful to note that other inter-activity conflicts occur in association with mountain bikes and walkers. For example, some walkers perceive conflicts with runners, despite both being low impact and "passive" foot traffic. This reinforces the notion that the "styles" of different activities and the perceptions associated with them are the fundamental basis of most conflicts. It provides some indication of what underlies walker attitudes to mountain bikes.

5.4 Setting and Experience Preferences

Managers are currently required to consider resource allocation decisions for mountain biking without any research information on what riders want. The only past experience of providing cycling opportunities has been based upon urban-style cycleways. While the majority of mountain-bike riders do not venture off-road, those who do are likely to be looking for something more.

Preference for challenging physical and technical riding, riding on routes in natural settings, and variety in riding experiences are the main preferences indicated by riders in the limited research results availible to date. For a small proportion of riders interested in racing, a degree of competitiveness was also present in the preferred riding experiences.