Environmental Related Issues

Roads can have both positive and negative influences on people and the environment. On the positive side roads provide the opportunity of mobility and transport for people and goods. On the negative side roads occupy land resources and form barriers to animals. They can also cause adverse impacts on natural water resources and discharge areas.

The three most damaging effects of road construction and management are noise, dust and vibrations. Noise mainly occurs during road construction phases but it can also occur to a lesser degree during maintenance operations. Dust is created during the construction of gravel roads and unbound aggregate layers.. Excess dust production can be treated by means such as watering, the use of alternative materials, and by using dust binders near houses. Vibration can be caused by uneven road surfaces and can pose significant impacts and problems to houses close to the source.

This lesson will focus on the environmental effects of noise, dust, vibrations, and other environmental concerns, and offer suggestions on how they can be mitigated.

4.1. Noise

Noise is defined as a sound that is undesirable to the listener. The level of the disturbance caused by sound will depend on its extent and intensity, and on the sensitivity of the persons affected. Noise is not normally a major problem for roads in the Northern Periphery as the region is generally relatively sparsely populated and the road networks on the whole run through uninhabited or lightly populated areas. Most roadworks in the Northern Periphery are usually carried out outside the built-up areas, with the result that the effect of noise on the local surroundings is not generally a special consideration. Standard working measures within the site must of course be observed.

The condition of roads also have an effect on noise level. For example if a road is in poor condition and cars are traveling fast, this can cause more noise than if the road is in better condition.

Greater consideration must therefore be given if roadworks are likely to create noise. Noise disturbances may cause irritation as well as agitation and stress to livestock.

A simple but fairly effective measure to manage the effects of noise is to notify the persons likely to be affected that work is about to start. This can be done by delivering information leaflets through letterboxes and/or by posting notices on notice boards. For major work, it may be sensible to convene an information meeting. If people are notified, their acceptance of the disturbance is usually higher. It is wise to work within normal working hours as much as possible. If this is impossible, the persons affected should be given special notification. There are only limited ways of reducing the noise level. Noise can obviously be reduced by noise fences or similar structures, but these are often impracticable on roadwork sites, particularly for minor works of short duration.

A general piece of advice that applies to noise is to use modern equipment wherever possible. Such equipment normally has better noise and vibration attenuation than older machines. Modern machinery also offers other benefits, such as reduced emissions, etc.

4.2 Vibrations

Vibrations disturb people close to roads but they may also cause damage to buildings and sensitive equipment. Vibrations, and also noise, can affect local fauna. Moreover, vibrations can cause damage to geological and archaeological objects.

A major source of vibrations to surrounding households are uneven roads with potholes and differential frost heave. Vibration levels can be different in winter when ground is frozen compared to summer. Vibrations caused by poor road conditions can be also a risk to the health of drivers as ROADEX research has shown [link: Johan Granlund report]

If vibrations are likely to be caused by roadworks, greater consideration should be given as to when the work should be done. As with the noise problems a simple and effective measure is to notify the persons about the planned roadworks so that they can be informed of their reason and duration.

Unnecessary high vibration sources, such as compaction with heavy vibration rollers or bedrock blasting, should be avoided or minimized in built-up areas. Heavy vibrations can cause damage to buildings and installations, which can give rise to damage claims. Methods and equipment that minimize vibrations should therefore be employed. This this is often difficult in practice however, since roadworks demand specialized mechanical equipment such as diggers, heavy trucks, etc. Closer hole spacings and lighter charges should be used where possible in blasting operations to reduce induced vibration in the surroundings.

A general piece of advice that applies to vibrations (and this rule applies to noise also) is to use modern equipment wherever possible. Such equipment normally has better noise and vibration attenuation than older machines. Modern machinery also offers other benefits, such as reduced emissions, etc.

As already mentioned, road condition can also affect vibration. For example heavy trucks passing over a road section with a large quantity of frost heave damages will create large vibrations. Keeping the road in a good and even condition will minimize the amount of vibration.

4.3 Dust

Dust is an almost inevitable consequence of roadwork. Gravel and crushed gravel and hard rock aggregates always contain a proportion of fines, and if the material is dry, a fairly heavy dust cloud can be raised when it is mobilized. The resulting dust can disturb both the population and the local environment.