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.