{{Short description|Type of road}} [[File:Alte Passwangstrasse November 2019 Bild 03.jpg|thumb|right|upright=1.2|A paved road in Switzerland transitioning to a gravel track]] An '''unpaved road''' is a type of [[road]] whose surface has not been [[sealed road|sealed]] with a pavement treatment,<ref>{{cite journal|last1=Leonardi|first1=Giovanni|first2=Dario|last2=Lo Bosco|first3=Rocco|last3=Palamara|first4=Federica|last4=Suraci|year=2020|title=Finite Element Analysis of Geogrid-Stabilized Unpaved Roads|journal=Sustainability|volume=12|number=5|page=1929|doi=10.3390/su12051929|doi-access=free}}</ref> such as [[concrete]] or [[bitumen]]. An unpaved road can be a [[dirt road]], whose surface is the native material of the land surface (known as [[subgrade]] material), or it could be a [[gravel road]], where the subgrade material has been covered by gravel but not sealed. There are approximately {{convert|13|e6km|e6mi|abbr=unit}} of unpaved road in the world, making up 57% of the total road length.<ref>{{cite web|url=https://onlinepubs.trb.org/onlinepubs/circulars/ec167.pdf|first=Asif|last=Faiz|title=The Promise of Rural Roads|id=Transportation Research Circular E-C167|publisher=Transportation Research Board of the National Academies|date=September 2012}}</ref>
==Types== {{refimprove section|date=January 2026}} ===Forest or logging road=== [[File:Dans la forêt d'Eseka1.jpg|thumb|Logging road near [[Eséka]] in [[Cameroon]]]] {{Main|Forest road}}
A forest road is a type of rudimentary access road, built by private companies, or government entities such as the [[Forest Service Road System|United States Forest Service]] to access remote undeveloped areas. These roads are built mainly for the purposes of forest management, [[timber harvest]], and [[grazing|livestock grazing]],<ref>{{cite journal|last1=Al-Chokhachy|first1=R|last2=Black|first2=TA|last3=Thomas|first3=C|display-authors=et al|year=2016|title=Linkages between unpaved forest roads and streambed sediment: why context matters in directing road restoration|journal=Restor Ecol|volume=24|pages=589-598|doi=10.1111/rec.12365}}</ref> although in some cases they are also used for [[backcountry]] recreation access.
Typically, a high-clearance four-wheel drive vehicle is required to travel effectively on a forest road, especially where large [[pothole]]s and/or [[waterbar]]s are present. [[hairpin turn|Switchback]]s are employed to make the road passable through steep terrain.
These roads rapidly fall into disrepair and quickly become impassable. Remnants of old roads can exist for decades. They are eventually erased by [[Washout (erosion)|washout]], [[erosion]], and [[ecological succession]].
[[Logging truck]]s are generally given right of way. In areas that the practice is regulated, on non-highway roads with heavy logging traffic may be "radio-controlled", meaning that a [[Citizens' band radio|CB radio]] on board any vehicle on the road is advised for safety reasons.
===Resource road=== According to the [[British Columbia]] Ministry of Forests, resource roads are typically "one- or two-lane gravel roads built for industrial purposes to access natural resources in remote areas".<ref name="Min. Forestry">{{Cite web |date=2021-04-15 |title=Resource roads |url=https://www2.gov.bc.ca/gov/content/industry/natural-resource-use/resource-roads |access-date=2022-10-28 |website=Ministry of Forests, Province of British Columbia}}</ref> They may be used by industrial vehicles or the general public, and as a link to rural communities.<ref name="Min. Forestry" /> Driving on resource roads can be hazardous for many reasons, including limited [[visibility]], unusual [[road geometry]], and the presence of [[wildlife]].<ref name="Min. Forestry" /> Disused resource roads can pose a danger to both drivers and passersby, due to the danger of [[landslide]]s forming on unstable, [[Drainage|poorly-drained]] ground.<ref>{{Cite news |last1=Brend |first1=Yvette |last2=Duncombe |first2=Lyndsay |date=2022-10-27 |title=Fatal landslide blamed on old logging road raises fears about hidden risks near Canada's highways |work=CBC News |url=https://www.cbc.ca/news/canada/british-columbia/landslide-risk-service-roads-1.6628050 |access-date=2022-10-28}}</ref>
===Primitive road=== [[Image:Foot transport on a dirty road.jpg|thumb|right|upright|A primitive road near [[Buwenda]], [[Uganda]]]]
A primitive road is a [[minor road]] system, used for travel or transportation that is generally not maintained or paved.<ref>{{cite book |title=ROS Users Guide |date=1982 |publisher=Forest Service |page=16 |url=https://books.google.com/books?id=xCIcxieP--wC&pg=PP20 |access-date=8 March 2020 |language=en}}</ref> Primitive roads primarily occur in rural farmlands, deserts, or forests rather than in developed areas.
There is no universal definition of primitive road. According to [[Washington (state)]] law, an unpaved road is a primitive road if: # It is not part of the county's [[county road|primary road system]] # It has an average annual daily traffic of one hundred or fewer vehicles.<ref name=Chelan>{{cite web|title=Primitive Roads|work=Public Works|publisher=County of Chelan|url=https://www.co.chelan.wa.us/public-works/pages/primitive-roads|access-date=2026-01-30}}</ref> [[Road maintenance]] on primitive roads is optional for the county in Washington.<ref name=Chelan/>
==Design and maintenance == The performance of unpaved roads is highly dependent on the properties of the underlying soil and the effectiveness of drainage systems. Proper design of unpaved roads includes consideration of material selection, compaction, and moisture control to ensure adequate bearing capacity and resistance to deformation. Unpaved roads are particularly sensitive to moisture variations and changes in groundwater conditions, which can significantly affect their bearing capacity and surface stability. Rising groundwater levels and prolonged wet conditions may lead to softening of the road structure, increased rutting, and reduced trafficability. Field studies have demonstrated that variations in groundwater table levels can directly influence the performance of gravel roads, highlighting the importance of drainage design and environmental considerations in maintaining long-term functionality.<ref>{{cite journal |last=Kuttah |first=D. |last2=Arvidsson |first2=H. |year=2017 |title=Effect of Groundwater Table Rising on the Performance of a Swedish-Designed Gravel Road |journal=Transportation Geotechnics |volume=11 |pages=82–96}}</ref> [[File:Egileta - Camino GR25 01.jpg|thumb|Gravel track in Spain]]
Research has shown that improved drainage solutions, such as the use of stone mattresses, can enhance the structural performance of unpaved and forest roads by facilitating water movement and reducing excess pore water pressure. This leads to improved load distribution and reduced deformation under traffic loading.<ref>{{cite journal |last=Kuttah |first=D. |last2=Persson |first2=J. |year=2025 |title=Stabilization through improved drainage using stone mattresses |journal=International Journal of Forest Engineering |pages=1–17 |doi=10.1080/14942119.2025.2544413}}</ref>
Recent advancements in unpaved roads monitoring include the use of unmanned aerial vehicles (UAVs) for surface condition assessment and profiling. Studies have shown that UAV-based techniques can provide accurate and efficient measurements of road surface characteristics, offering a promising alternative to traditional methods such as road surface testers and laser-based systems.<ref>{{cite journal |last=Kuttah |first=D. |last2=Waldemarson |first2=A. |year=2024 |title=Next generation gravel road profiling – The potential of advanced UAV drone in comparison with road surface tester and rotary laser levels |journal=Transportation Engineering |volume=27 |doi=10.1016/j.treng.2024.100260}}</ref>
==Driving hazards== While most gravel roads are all-weather roads and can be used by ordinary [[car]]s, dirt roads may only be passable by [[truck]]s or [[four-wheel drive]] [[vehicle]]s, especially in wet weather, or on rocky or very sandy sections. It is as easy to become bogged in sand as it is in mud; a high clearance under the vehicle may be required for rocky sections.{{Cn|date=December 2022}}
Driving on unpaved roads presents hazards often not present on paved or sealed roads: *Dust can be thrown up from a passing vehicle reducing visibility.<ref>{{cite book|chapter=Unpaved Roads as Sources of Fugitive Dust|pages=94-97|first1=RL|last1=Handy|first2=JM|last2=Hoover|first3=KL|last3=Bergeson|first4=DE|last4=Fox|title=Hearings, Reports and Prints of the Senate Committee on Agriculture and Forestry|publisher=US Government Printing Office|year=1975}}</ref> *[[Washboarding|Washboard]] corrugations cause loss of control due to lack of tire contact.<ref>{{cite web|url=https://jacksoncountyor.gov/departments/roads/general_information/gravel_roads.php|title=Gravel Roads|publisher=Jackson County, Oregon|date=2026-01-31}}</ref> These are most often found near intersections as stopping or braking causes them to form.<ref>{{cite web|url=https://www.salinecountyks.gov/media/Road%20and%20Bridge/documents/Washboards.pdf?ver=20260122172610|title=Gravel Road Washboards|first=Norm|last=Bowers|work=On The Road|publisher=Saline County, Kansas}}</ref> *Skidding on mud after rain<ref name=ucanr>{{cite web|title=Off-road driving safety|url=https://ucanr.edu/sites/default/files/2019-02/298544.pdf|id=Safety Note #195|publisher=University of California Agriculture and Natural Resources}}</ref> *Vehicle [[fishtailing]] as a result of ruts in the surface. Often found on frequently traveled roads. *In higher rainfall areas, the increased camber required to drain water, and open drainage ditches at the sides of the road, often cause vehicles with a high [[centre of gravity]], such as trucks and off-road vehicles, to overturn if they do not keep close to the crown of the road. *Many unpaved roads are only [[single track road|one lane wide]] or slightly larger, thus requiring special attention when driving at higher speeds.
==Length by country==
The CIA Worldbook provides an estimate of the total length of unpaved roads per country for most, but not all countries in the world. The top 10 countries with the largest amount of roads is shown in the table, below:<ref name=cia>{{cite web|url=https://www.cia.gov/the-world-factbook/about/archives/2023/field/roadways/|archive-url=https://web.archive.org/web/20250716013016/https://www.cia.gov/the-world-factbook/about/archives/2023/field/roadways|url-status=dead|archive-date=July 16, 2025|title=Roadways|work=CIA World Factbook|year=2023}}</ref> {| class="wikitable sortable" ! data-sort-type=number | Rank ! Country ! data-sort-type=number | Length of unpaved roads (km) |- |1 |United States |2,281,895 |- |2 |Brazil |1,754,000 |- |3 |Australia |727,645 |- |4 |Canada |626,700 |- |5 |China |622,000 |- |6 |Mexico |529,358 |- |7 |South Africa |591,876 |- |8 |Sweden |433,034 |- |8 |Russia |355,666 |- |10 |Finland |350,000 |}
== External links == * [https://www.youtube.com/watch?v=1MufrBcZ4HQ Development of forest roads in Sweden – research project overview]
==See also== {{div col|colwidth=20em}} * [[Byway (United Kingdom)|Byway (road)]] * [[Country lane]] * [[Dirt road]] * [[Forest Highway]] * [[Forest railway]] * [[Forest road]] * [[Gravel road]] * [[Logging]] * [[Road]]s * [[Road surface]] * [[Track bed]] * [[Trail]] {{div col end}}
==References== {{reflist}}
{{Road types}} {{Sister bar|auto=1}}
[[Category:Types of roads]]