1.1.What is a gravel road
Throughout history people and animals have used paths across terrain to make it easy to walk and it is difficult to tell when these paths could be termed roads. Many of the early tracks in Scotland (“drove roads”) and Finland (“cow paths”) came about as recognised ways of getting cattle from rural areas to the main markets in cities.
According to different sources the history of built gravel roads can go back to the first section of the ancient Silk Road 500 BC, when the Persian Royal Road was built. In the ROADEX area the first specially built gravel road was made by Scottish John Metcalfe (born in 1717) in Yorkshire, England. This road had three layers: large stones in the bottom, a mixture of road material and a layer of gravel on the top. Later two other Scottish engineers, Thomas Telford and John Loudon McAdam improved the road cross-section by raising the foundation of the road in the centre for easier water drainage. Telford improved gravel road building further by analyzing stone thickness, road traffic, road alignment and gradient slopes (FHWA, History of Gravel Roads).
The terminology for gravel roads also varies country by country. These have been variously named as unsealed roads, aggregate roads or dirt roads. Dirt roads differ slightly from the others as they were built from materials at the sides of the roads.
Gravel roads can be classified by their history and how they have been built. For instance, in Finland gravel roads have been classified into two classes: a) unbuilt (historical) gravel roads that are a result of their evolution history and b) built gravel roads, that have been designed and built for a particular purpose. Gravel roads can be classified also based on their function to serve society. A good example is Iceland where there are five different gravel road categories.
35 Primary Highland Road
35 Primary Highland Road
35 Primary Highland Road
54 Primary Road
85 Primary Road
94 Secondary Road
208 Local Access Road
208 Primary Highland Road
302 Local Access Road
355 Local Access Road
367 Secondary Road
431 Secondary Road
460 Secondary Road
510 Secondary Road
533 Secondary Road
570 Highland Road
579 Secodary Road
590 Secondary Road
608 Secondary Road
612 Secondary Road
615 Local Access Road
617 Local Access Road
626 Highland Road
643 Secondary Road
649 Highland Road
702 Secondary Road
704 Secondart Road
711 Secondary Road
717 Secondary Road
731 Secondary Road
748 Secondary Road
793 Highland Road
821 Highland Road
832 Highland Road
833 Local Access Road
842 Primary Road
864 Secondary Road
864 Secondary Road
864 Local Access Road
901 Highland Road
910 Highland Road
917 Primary Road
939 Secondary Road
7234 Local Access Road
9669 Local Access Road
F249 Highland Road
F910 Highland Road
F899 Highland Road
F881 Highland Road
F839 Highland Road
F839 Highland Road
F821 Highland Road
F821 Highland Road
F752 Highland Road
F586 Highland Road
F224 Highland Road
F26 Primary Highland Road
F26 Primary Highland Road
Most daily journeys on public roads are generally on paved roads but in the ROADEX area 1/3 of public roads are still gravel roads. The overall total length of gravel roads however in most countries is much longer than paved roads. This is because the greater proportion of private rural roads are gravel roads and forest roads. For instance in USA there are more than 2.2 million km of public gravel roads, even though the normal image for roads in US is of paved roads. And in many countries the share of gravel roads is even increasing because their annual maintenance costs are lower compared to poor condition paved roads. Table 1 provides information of the length of gravel and forest roads in ROADEX partner countries.
Ireland | Scotland | Iceland | Norway | Sweden | Finland | |
Public gravel roads | – | – | 7,135 km | 13,680 km | 21,200 km | 27,300 km |
Forest roads | 11,360 km | 20,000 km | – | 49,630 km | 280,000 km | 125,000 km |
Table 1. Public gravel roads and forest roads in ROADEX partner countries
1.2. What is a forest road
A forest road is a special class of road that has a particular function. According to Wikipedia “Forest roads or forest tracks are roads or tracks intended to carry motorised vehicles or horse-drawn wagons being used mainly or exclusively for forestry purposes, such as conservation or logging. Forest roads may be open to ramblers or mountain bikers depending on local rules”. And even though a minority of forest roads are paved, it can be generally stated that all forest roads are gravel roads. A special feature of many forest roads is that many of them are not connecting roads, but are mainly for hauling timber from forest to factories or sawmills. For this reason many are “dead end” roads with a turning place at the end of the road.
Because of their nature a special feature of forest roads is that they do not have be kept open all year round. Especially during wintertime, many forest roads are kept open only when there are forest extraction operations in the area. Forest roads are generally not public owned, but are owned by private landowners or forest companies. The length of forest roads can be quite high especially in the countries with forest industries. In Finland 36% of 350,000 km long low volume road network is forest roads. Of these 77,000 km of them are located in private owned forests, 20,000 km in private forest company properties and 27,000 km on state owned land.
The location and ownership of the 125,000 km long forest road network in Finland.
1.3. The importance of gravel roads
Gravel roads are an essential part of the “blood vascular system” of the transportation infrastructure. They provide access to many rural communities and they act as a transportation route for products to markets. For instance, in most cases the beginning of the transportation routes for products of the farming, forest and aggregate industries have gravel surfaces. In addition gravel and forest roads have a critical role in forest fire management as well as defence training. And finally gravel roads have a great role in recreational, social and tourism activities.