This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (April 2007)

A high-speed toll booth on SR 417 near Orlando, Florida, United States

A toll plaza in the United Kingdom

A toll road (also tollway, turnpike, toll highway, or express toll route) is a privately or publicly built road for which the driver is required to pay a fee, or toll. Fees were traditionally collected by hand at toll booth, toll house, toll plaza, toll station, toll bar or toll gate, but nowadays more tolls are implementing some form of automatic or electronic toll collection.

In addition to toll roads, toll bridges and toll tunnels are also used by public authorities for revenue generation to repay for long-term debt issued to finance the toll facility, or to reinvest in capacity expansion or used to pay for operations and maintenance of the facility, or simply as general tax funds. Also road congestion pricing schemes have been implemented in a limited number of urban areas as a transportation demand management tool to reduce traffic congestion and air pollution.^[1]

History[link]

A table of tolls in pre-decimal currency for the College Road, Dulwich, London SE21 tollgate.

Mythology[link]

Tolls are mentioned in Greek mythology where Charon the ferryman charged a toll to carry the dead across the rivers Acheron and Styx to Hades. If the soul paid a toll, Charon ferried it across the river. If not, it wandered between death and life for eternity.

Ancient times[link]

Toll roads are at least 2700 years old, as tolls had to be paid by travellers using the Susa–Babylon highway under the regime of Ashurbanipal, who reigned in the seventh century BC.^[2] Aristotle and Pliny refer to tolls in Arabia and other parts of Asia. In India, before the 4th century BC, the Arthasastra notes the use of tolls. Germanic tribes charged tolls to travellers across mountain passes. Tolls were used in the Holy Roman Empire in the 14th century and 15th century.

Middle ages[link]

A 14th century example (though not for a road) is Castle Loevestein in the Netherlands, which was built at a strategic point where 2 rivers meet, and charged tolls on boats sailing along the river.

Many modern European roads were originally constructed as toll roads in order to recoup the costs of construction. In 14th century England, some of the most heavily used roads were repaired with money raised from tolls by pavage grants.

Turnpikes[link]

19th century toll booth in Kings County, New York

Plaque commemorating the suppression of toll on a York (G-B) bridge in 1914.

Turnpike trusts were established in England from 1706 onwards, and were ultimately responsible for the maintenance and improvement of most main roads in England and Wales, until they were gradually abolished from the 1870s. Most trusts improved existing roads, but some new ones, usually only short stretches of road, were also built. Thomas Telford's Holyhead road (now the A5 road) is exceptional as a particularly long new road, built in the early 19th century with many toll booths along its length. See also Toll roads in the United Kingdom.

Some cities in Canada had toll roads in the 19th Century. Roads radiating from Toronto required users to pay at toll gates along the street (Yonge Street, Bloor Street, Davenport Road, Kingston Road)^[3] and disappeared after 1895.^[4]

19th century plank roads were usually operated as toll roads. One of the first U.S. motor roads, the Long Island Motor Parkway (which opened on October 10, 1908) was built by William Kissam Vanderbilt II, the great-grandson of Cornelius Vanderbilt. The road was closed in 1938 when it was taken over by the state of New York in lieu of back taxes.^[5][6]

20th Century[link]

In the 20th century, road tolls have been introduced in Europe for financing the construction of motorway networks and specific road infrastructure such as bridges and tunnels. Italy has been the first European country to apply the use of motorway tolls on a 50 km motorway section near Milan in 1924. It was followed by Greece, which made users to pay for the network of motorways around and between its cities in 1927. Later in the 1950s and 1960s, also France, Spain and Portugal started to build motorways largely with the aid of concessions, allowing rapid development of this infrastructure without massive State debts. Since then, road tolls have been introduced in the majority of the EU Member States.^[7]

Charging methods[link]

Road tolls were levied traditionally for a specific access (e.g. city) or for a specific infrastructure (e.g. roads, bridges). These concepts were widely used until the last century. However, the evolution in technology made it possible to implement road tolling policies based on different concepts. The different charging concepts are designed to suit different requirements regarding purpose of the charge, charging policy, the network to the charge, tariff class differentiation etc.:^[8]

Time Based Charges and Access Fees: In a time-based charging regime, a road user has to pay for a given period of time in which he may use the associated infrastructure. For the practically identical access fees, the user pays for the access to a restricted zone for a period or several days.

Motorway and other Infrastructure Tolling: The term tolling is used for charging a well-defined special and comparatively costly infrastructure, like a bridge, a tunnel, a mountain pass, a motorway concession or the whole motorway network of a country. Classically a toll is due when a vehicle passes a tolling station, be it a manual barrier-controlled toll plaza or a free-flow multi-lane station.

Distance or Area Charging: In a distance or area charging system concept, vehicles are charged per total distance driven in a defined area.

Some toll roads charge a toll in only one direction. Examples include the Severn Bridges where M4 in Great Britain crosses the River Severn, crossings between Pennsylvania and New Jersey operated by Delaware River Port Authority, and crossings between New Jersey and New York operated by Port Authority of New York and New Jersey. This technique is practical where the detour to avoid the toll is large or the toll differences are small.

Collection methods[link]

ERP gantry at North Bridge Road. Singapore

The open road tolling lanes at the West 163rd Street toll plaza, on the Tri-State Tollway near Hazel Crest, Illinois, United States

Balintawak Toll Barrier, Balintawak, Caloocan, Philippines.

Calamba Toll Barrier, Calamba City, Laguna, Philippines.

Traditionally tolls were paid by hand to at a toll gate. It is more common now for payments may be made in cash, by credit card, by pre-paid card, or by an electronic toll collection system. In some European countries, payment is made using stickers which are affixed to the windscreen.

Three systems of toll roads exist: open (with mainline barrier toll plazas); closed (with entry/exit tolls) and open road (no toll booths, only electronic toll collection gantries at entrances and exits, or at strategic locations on the mainline of the road). Modern toll roads often use a combination of the three, with various entry and exit tolls supplemented by occasional mainline tolls: for example the Massachusetts Turnpike or "MassPike," the Pennsylvania Turnpike and the New York State Thruway implement both systems in different sections.

On an open toll system, all vehicles stop at various locations along the highway to pay a toll. While this may save money from the lack of need to construct toll booths at every exit, it can cause traffic congestion while traffic queues at the mainline toll plazas (toll barriers). It is also possible for motorists to enter an 'open toll road' after one toll barrier and exit before the next one, thus travelling on the toll road toll-free. Most open toll roads have ramp tolls or partial access junctions to prevent this practice, known as "shunpiking".

With a closed system, vehicles collect a ticket when entering the highway. In some cases, the ticket displays the toll to be paid on exit. Upon exit, the driver must pay the amount listed for the given exit. Should the ticket be lost, a driver must typically pay the maximum amount possible for travel on that highway. Short toll roads with no intermediate entries or exits may have only one toll plaza at one end, with motorists traveling in either direction paying a flat fee either when they enter or when they exit the toll road. In a variant of the closed toll system, mainline barriers are present at the two endpoints of the toll road, and each interchange has a ramp toll that is paid upon exit or entry. In this case, a motorist pays a flat fee at the ramp toll and another flat fee at the end of the toll road; no ticket is necessary. In addition, with most systems, motorists may only pay tolls with cash and/or change; debit and credit cards are not accepted. However, some toll roads may have travel plazas with ATMs so motorists can stop and withdraw cash for the tolls.

The toll is calculated by the distance travelled on the toll road. In the United States, for instance, the Kansas Turnpike, Ohio Turnpike, Pennsylvania Turnpike, New Jersey Turnpike, most of the Indiana Toll Road, and portions of the Massachusetts Turnpike, New York Thruway, and Florida's Turnpike currently implement closed systems.

The Union Toll Plaza on the Garden State Parkway was the first ever to use an automated toll collection machine. A plaque commemorating the event includes the first quarter collected at its toll booths.^[9]

The first major deployment of an RFID electronic toll collection system in the United States was on the Dallas North Tollway in 1989 by Amtech (see TollTag). The Amtech RFID technology used on the Dallas North Tollway was originally developed at Sandia Labs for use in tagging and tracking livestock. In the same year, the Telepass active transponder RFID system was introduced across Italy.

Highway 407 in the province of Ontario, Canada has no toll booths, and instead reads a transponder mounted on the windshields of each vehicle using the road (the rear license plates of vehicles lacking a transponder are photographed when they enter and exit the highway). This made the highway the first all-automated highway in the world. A bill is mailed monthly for usage of the 407. Lower charges are levied on frequent 407 users who carry electronic transponders in their vehicles. The approach has not been without controversy: In 2003 the 407 ETR settled^[10] a class action with a refund to users.

Throughout most of the East Coast of the United States, E-ZPass (operated under the brands I-Pass in Illinois, i-Zoom in Indiana, and Fast Lane in Massachusetts) is accepted on almost all toll roads. Similar systems include SunPass in Florida, FasTrak in California, and ExpressToll in Colorado. The systems use a small radio transponder mounted in or on a customer's vehicle to deduct toll fares from a pre-paid account as the vehicle passes through the toll barrier. This reduces manpower at toll booths and increases traffic flow and fuel efficiency by reducing the need for complete stops to pay tolls at these locations.

E-ZPass lanes at a New Jersey Turnpike (I-95) Toll Gate for Exit 8A in Monroe Township, New Jersey, United States.

By designing a tollgate specifically for electronic collection, it is possible to carry out open-road tolling, where the customer does not need to slow at all when passing through the tollgate. The U.S. state of Texas is testing a system on a stretch of Texas 121 that has no toll booths. Drivers without a TollTag have their license plate photographed automatically and the registered owner will receive a monthly bill, at a higher rate than those vehicles with TollTags.^[11]

The first all-electric toll road in the eastern United States, the InterCounty Connector (Maryland Route 200) was partially opened to traffic in February 2011.^[12] Another all-electronic toll road, the Triangle Parkway, will open at the end of 2011 in North Carolina.^[13]

Financing and management[link]

Some toll roads are managed under such systems as the Build-Operate-Transfer (BOT) system. Private companies build the roads and are given a limited franchise. Ownership is transferred to the government when the franchise expires. Throughout the world, this type of arrangement is prevalent in Australia, Canada, Hong Kong, India, South Korea, Japan and the Philippines. The (BOT) system is a fairly new concept that is gaining ground in the United States, with Arkansas, California, Delaware, Florida, Illinois, Indiana, Mississippi,^[14] Texas, and Virginia already building and operating toll roads under this scheme. Pennsylvania, Massachusetts, New Jersey, and Tennessee are also considering the BOT methodology for future highway projects.

The more traditional means of managing toll roads in the United States is through semi-autonomous public authorities. New York, Massachusetts, New Hampshire, New Jersey, Maryland, Ohio, Pennsylvania, North Carolina, Kansas, Oklahoma, and West Virginia manage their toll roads in this manner. While most of the toll roads in California, Delaware, Florida, Texas, and Virginia are operating under the BOT arrangement, a few of the older toll roads in these states are still operated by public authorities.

In France, all toll roads are operated by private companies, and the government takes a part of their profit.^{[citation needed]}

Criticism[link]

Toll roads have been criticized as being inefficient in various ways:^[15]

1. They require vehicles to stop or slow down, manual toll collection wastes time and raises vehicle operating costs.
2. Collection costs can absorb up to one-third of revenues, and revenue theft is considered to be comparatively easy.
3. Where the tolled roads are less congested than the parallel "free" roads, the traffic diversion resulting from the tolls increases congestion on the road system and reduces its usefulness.
4. By tracking the vehicle locations, their drivers are subject to an effectual restriction of their freedom of movement and freedom from excessive surveillance.

See also[link]

Wikimedia Commons has media related to: Toll roads

• List of toll roads
• High-occupancy toll
• Private highway
• Road pricing
• Shadow toll
• Shunpiking, the practice of avoiding turnpikes.
• The Phantom Tollbooth, a children's novel
• Toll house
• Barrier toll system
• Toll roads around the world

References[link]

Part of a series on Government
Public finance
Policies Economic policy Fiscal policy · Monetary policy Trade policy · Investment policy Agricultural policy · Industrial policy Energy policy · Social policy Policy mix
Fiscal policy Tax policy · Budgetary policy Revenue · Spending · Budget Deficit or Surplus · Deficit spending Debt (External · Internal) Finance ministry · Fiscal union
Monetary policy Money supply · Interest rate Monetary base · Discount window Reserve requirements Bank reserves · Gold reserves Monetary authority (central bank · currency board) · Monetary union
Trade policy Tariff · Non-tariff barrier Balance of trade · Gains from trade Trade creation · Trade diversion Protectionism · Free trade Commerce ministry · Trade bloc
Revenue and Spending Tax revenue · Non-tax revenue Mandatory spending Discretionary spending
Optimum Balanced budget (fiscal) Price stability (monetary) Growth (trade and investment)
Reform Fiscal adjustment · Monetary reform
v t e

External links[link]

• Overview of European Tolling Systems
• International Bridge, Tunnel and Turnpike Association The International Bridge, Tunnel and Turnpike Association (IBTTA) is the worldwide alliance of toll operators and associated industries that provides a forum for sharing knowledge and ideas to promote and enhance toll-financed transportation services.
• Turnpikes and Toll Roads in Nineteenth-Century America (EH.Net Economic History encyclopaedia)
• Collection of tollroad news from contractor perspective
• English Turnpike roads, for background on toll roads during the turnpike era in England
• For a Toll free Democracy, Anti Toll Movement in Kerala, India

A road is a route, thoroughfare or way that supports travel by a means of conveyance.

Definitions[link]

For purposes of international statistical comparison, the Organisation for Economic Co-operation and Development (OECD) defines a road as "a line of communication (travelled way) using a stabilized base other than rails or air strips open to public traffic, primarily for the use of road motor vehicles running on their own wheels," which includes "bridges, tunnels, supporting structures, junctions, crossings, interchanges, and toll roads, but not cycle paths."^[1] In urban areas roads may diverge through a city or village and be named as streets, serving a dual function as urban space easement and route.^[2] Modern roads are normally smoothed, paved, or otherwise prepared to allow easy travel.^[3] Historically many roads were simply recognizable routes without any formal construction or maintenance.^[4]

United States[link]

In the United States, laws distinguish between public roads, which are open to public use, and private roads, which are privately controlled.^[5]

United Kingdom[link]

In the United Kingdom there is some ambiguity between the terms highway and road. The Highway code details rules for "road users".^[6] For the purposes of the English law, Highways Act 1980, which covers England and Wales but not Scotland or Northern Ireland, the term road is defined to be "any length of highway or of any other road to which the public has access, and includes bridges over which a road passes."^[7] This includes footpaths, bridleways and cycle tracks, and also road and driveways on private land and many car parks.^[8] Vehicle Excise Duty, a road use tax, is payable on some vehicles used on the public road.^[8]

The definition of a road depends on the definition of a highway, however there is no formal definition for a highway in the relevant Act. A 1984 ruling said "the land over which a public right of way exists is known as a highway; and although most highways have been made up into roads, and most easements of way exist over footpaths, the presence or absence of a made road has nothing to do with the distinction.^[9][10] Another legal view is that while a highway historically included footpaths, bridleways, driftways, etc., it can now be used to mean those ways that allow the movement of motor-vehicles, and the term rights of way can be used to cover the wider usage.^[11]

Historical road construction[link]

The Porta Rosa is a Greek street dating from the 3rd to 4th century BC in Velia, Italy with a paved surface and gutters.

A paved Roman road in Pompeii, Italy

The assertion that the first pathways were the trails made by animals has not been universally accepted, since in many cases animals do not follow constant paths.^[4] Others believe that some roads originated from following animal trails.^[12][13] The Icknield Way is given as an example of this type of road origination, where man and animal both selected the same natural line.^[14] By about 10,000 BC, rough pathways were used by human travelers.^[4]

• The world's oldest known paved road was laid in Egypt some time between 2600 and 2200 BC.^[15]

• Stone-paved streets are found in the city of Ur in the Middle East dating back to 4000 BC.^[4]

• Corduroy roads (log roads) are found dating to 4000 BC in Glastonbury, England.^[4]

• The timber trackway; Sweet Track causeway in England, is one of the oldest engineered roads discovered and the oldest timber trackway discovered in Northern Europe. Built in winter 3807 BC or spring 3806 BC, tree-ring dating (Dendrochronology) enabled very precise dating. It has been claimed to be the oldest road in the world.^[16][17]

• Brick-paved streets were used in India as early as 3000 BC .^[4]

• In 500 BC, Darius I the Great started an extensive road system for Persia (Iran), including the famous Royal Road, which was one of the finest highways of its time.^[18] The road remained in use after Roman times.

• In ancient times, transport by river was far easier and faster than transport by road,^[17] especially considering the cost of road construction and the difference in carrying capacity between carts and river barges. A hybrid of road transport and ship transport beginning in about 1740 is the horse-drawn boat in which the horse follows a cleared path along the river bank.^[19][20]

• From about 312 BC, the Roman Empire built straight^[21] strong stone Roman roads throughout Europe and North Africa, in support of its military campaigns. At its peak the Roman Empire was connected by 29 major roads moving out from Rome and covering 78,000 kilometers or 52,964 Roman miles of paved roads.^[17]

• In the 8th century AD, many roads were built throughout the Arab Empire. The most sophisticated roads were those in Baghdad, Iraq, which were paved with tar. Tar was derived from petroleum, accessed from oil fields in the region, through the chemical process of destructive distillation.^[22]

• The Highways Act 1555 in Britain transferred responsibility for maintaining roads from government to local parishes.^[17] This resulted in a poor and variable state of roads. To remedy this, the first of the "Turnpike trusts" was established around 1706, to build good roads and collect tolls from passing vehicles. Eventually there were approximately 1,100 trusts in Britain and some 36,800 km (22,870 miles) of engineered roads.^[17] The Rebecca Riots in Carmarthenshire and Rhayader from 1839 to 1844 contributed to a Royal Commission that led to the demise of the system in 1844,^[23] which coincided with the development of the UK railway system.

Design[link]

Structural road design is the science of designing a road for its environment in order to extend its longevity and reduce maintenance. The Shell pavement design method is used in many countries for the design of new asphalt roads.

Construction[link]

A road being torn up.

Surveyor at work with a leveling instrument.

Asphalt layer and roller

Road construction requires the creation of a continuous right-of-way, overcoming geographic obstacles and having grades low enough to permit vehicle or foot travel.^{[24] (pg15)} and may be required to meet standards set by law^[25] or official guidelines.^[26] The process is often begun with the removal of earth and rock by digging or blasting, construction of embankments, bridges and tunnels, and removal of vegetation (this may involve deforestation) and followed by the laying of pavement material. A variety of road building equipment is employed in road building.^[27][28]

After design, approval, planning, legal and environmental considerations have been addressed alignment of the road is set out by a surveyor.^[21] The Radii and gradient are designed and staked out to best suit the natural ground levels and minimize the amount of cut and fill.^{[26] (page34)} Great care is taken to preserve reference Benchmarks ^{[26] (page59)}

Roads are designed and built for primary use by vehicular and pedestrian traffic. Storm drainage and environmental considerations are a major concern. Erosion and sediment controls are constructed to prevent detrimental effects. Drainage lines are laid with sealed joints in the road easement with runoff coefficients and characteristics adequate for the land zoning and storm water system. Drainage systems must be capable of carrying the ultimate design flow from the upstream catchment with approval for the outfall from the appropriate authority to a watercourse, creek, river or the sea for drainage discharge.^{[26] (page38 to 40)}

Road construction on Marquette Avenue in Minneapolis, Minnesota, United States

A borrow pit (source for obtaining fill, gravel, and rock) and a water source should be located near or in reasonable distance to the road construction site. Approval from local authorities may be required to draw water or for working (crushing and screening) of materials for construction needs. The top soil and vegetation is removed from the borrow pit and stockpiled for subsequent rehabilitation of the extraction area. Side slopes in the excavation area not steeper than one vertical to two horizontal for safety reasons.^{[26] (page 53 to 56 )}

Old road surfaces, fences, and buildings may need to be removed before construction can begin. Trees in the road construction area may be marked for retention. These protected trees should not have the topsoil within the area of the tree's drip line removed and the area should be kept clear of construction material and equipment. Compensation or replacement may be required if a protected tree is damaged. Much of the vegetation may be mulched and put aside for use during reinstatement. The topsoil is usually stripped and stockpiled nearby for rehabilitation of newly constructed embankments along the road. Stumps and roots are removed and holes filled as required before the earthwork begins. Final rehabilitation after road construction is completed will include seeding, planting, watering and other activities to reinstate the area to be consistent with the untouched surrounding areas.^{[26] (page 66 to 67 )}

Processes during earthwork include excavation, removal of material to spoil, filling, compacting, construction and trimming. If rock or other unsuitable material is discovered it is removed, moisture content is managed and replaced with standard fill compacted to 90% relative compaction. Generally blasting of rock is discouraged in the road bed. When a depression must be filled to come up to the road grade the native bed is compacted after the topsoil has been removed. The fill is made by the "compacted layer method" where a layer of fill is spread then compacted to specifications, the process is repeated until the desired grade is reached.^{[26] (page 68 to 69 )}.

Line marking

General fill material should be free of organics, meet minimum California bearing ratio (CBR) results and have a low plasticity index. The lower fill generally comprises sand or a sand-rich mixture with fine gravel, which acts as an inhibitor to the growth of plants or other vegetable matter. The compacted fill also serves as lower-stratum drainage. Select second fill (sieved) should be composed of gravel, decomposed rock or broken rock below a specified Particle size and be free of large lumps of clay. Sand clay fill may also be used. The road bed must be "proof rolled" after each layer of fill is compacted. If a roller passes over an area without creating visible deformation or spring the section is deemed to comply.^{[26] (page 70 to 72 )}

Geosynthetics such as geotextiles, geogrids and geocells are frequently used in the various pavement layers to improve road quality. Geosynthetics perform four main functions in roads: separation, reinforcement, filtration and drainage; which increase the pavement performance, reduce construction costs and decrease maintenance.^[29]

The completed road way is finished by paving or left with a gravel or other natural surface. The type of road surface is dependent on economic factors and expected usage. Safety improvements like Traffic signs, Crash barriers, Raised pavement markers, and other forms of Road surface marking are installed.

According to a May 2009 report by the American Association of State Highway and Transportation Officials (AASHTO) and TRIP—a national transportation research organization—driving on rough roads costs the average American motorist approximately $400 a year in extra vehicle operating costs. Drivers living in urban areas with populations more than 250,000 are paying upwards of $750 more annually because of accelerated vehicle deterioration, increased maintenance, additional fuel consumption, and tire wear caused by poor road conditions.

When a single carriageway road is converted into dual carriageway by building a second separate carriageway alongside the first, it is usually referred to as duplication,^[30] twinning or doubling. The original carriageway is changed from two-way to become one-way, while the new carriageway is one-way in the opposite direction. In the same way as converting railway lines from single track to double track, the new carriageway is not always constructed directly alongside the existing carriageway.

Maintenance[link]

"Road works ahead" sign, typically used in Europe

Like all structures, roads deteriorate over time. Deterioration is primarily due to accumulated damage from vehicles, however environmental effects such as frost heaves, thermal cracking and oxidation often contribute.^[31] According to a series of experiments carried out in the late 1950s, called the AASHO Road Test, it was empirically determined that the effective damage done to the road is roughly proportional to the Fourth power of axle weight.^[32] A typical tractor-trailer weighing 80,000 pounds (36.287 t) with 8,000 pounds (3.629 t) on the steer axle and 36,000 pounds (16.329 t) on both of the tandem axle groups is expected to do 7,800 times more damage than a passenger vehicle with 2,000 pounds (0.907 t) on each axle. Potholes on roads are caused by rain damage and vehicle braking or related construction works.

Manual road repair taking place in Howrah, India.

Pavements are designed for an expected service life or design life. In some UK countries the standard design life is 40 years for new bitumen and concrete pavement. Maintenance is considered in the whole life cost of the road with service at 10, 20 and 30 year milestones.^[33] Roads can be and are designed for a variety of lives (8-, 15-, 30-, and 60-year designs). When pavement lasts longer than its intended life, it may have been overbuilt, and the original costs may have been too high. When a pavement fails before its intended design life, the owner may have excessive repair and rehabilitation costs. Many concrete pavements built since the 1950s have significantly outlived their intended design lives.^[34] Some roads like Chicago, Illinois's "Wacker Drive", a major two-level viaduct in downtown area are being rebuilt with a designed service life of 100 years.^[35]

Virtually all roads require some form of maintenance before they come to the end of their service life. Pro-active agencies use pavement management techniques to continually monitor road conditions and schedule preventive maintenance treatments as needed to prolong the lifespan of their roads. Technically advanced agencies monitor the road network surface condition with sophisticated equipment such as laser/inertial Profilometers. These measurements include road curvature, cross slope, asperity, roughness, rutting and texture (roads). This data is fed into a pavement management system, which recommends the best maintenance or construction treatment to correct the damage that has occurred.

Maintenance treatments for asphalt concrete generally include crack sealing, surface rejuvenating, fog sealing, micro-milling and surface treatments. Thin surfacing preserves, protects and improves the functional condition of the road while reducing the need for routing maintenance, leading to extended service life without increasing structural capacity.^[36]

Failure to maintain roads properly can create significant costs to society, in a 2009 report released by the American Association of State Highway and Transportation Officials (USA) about 50% of the roads in the USA are in bad condition with urban areas worse. The report estimates that urban drivers pay an average of $746/year on vehicle repairs while the average US motorist pays about $335/year. In contrast, the average motorist pays about $171/year in road maintenance taxes (based on 600 gallons/year and $0.285/gallon tax).

Slab Stabilization[link]

Distress and serviceability loss on concrete roads can be caused by loss of support due to voids beneath the concrete pavement slabs. The voids usually occur near cracks or joints due to surface water infiltration. The most common causes of voids are pumping, consolidation, subgrade failure and bridge approach failure. Slab stabilization is a non-destructive method of solving this problem and is usually employed with other Concrete Pavement Restoration (CPR) methods including patching and diamond grinding. The technique restores support to concrete slabs by filing small voids that develop underneath the concrete slab at joints, cracks or the pavement edge. The process consists of pumping a cementitous grout or polyurethane mixture through holes drilled through the slab. The grout can fill small voids beneath the slab and/or sub-base. The grout also displaces free water and helps keep water from saturating and weakening support under the joints and slab edge after stabilization is complete. The three steps for this method after finding the voids are locating and drilling holes, grout injection and post-testing the stabilized slabs.

Slab stabilization does not correct depressions, increase the design structural capacity, stop erosion or eliminate faulting. It does, however, restore the slab support, therefore, decreasing deflections under the load. Stabilization should only be performed at joints and cracks where loss of support exists. Visual inspection is the simplest manner to find voids. Signs that repair is needed are transverse joint faulting, corner breaks and shoulder drop off and lines at or near joints and cracks. Deflection testing is another common procedure utilized to locate voids. It is recommended to do this testing at night as during cooler temperatures, joints open, aggregate interlock diminishes and load deflections are at their highest.

Testing[link]

Ground penetrating radar pulses electromagnetic waves into the pavement and measures and graphically displays the reflected signal. This can reveal voids and other defects.

The epoxy/core test, detects voids by visual and mechanical methods. It consists of drilling a 25 to 50 millimeter hole through the pavement into the sub-base with a dry-bit roto-hammer. Next, a two-part epoxy is poured into the hole—dyed for visual clarity. Once the epoxy hardens, technicians drill through the hole. If a void is present, the epoxy will stick to the core and provide physical evidence.

Common stabilization materials include pozzolan-cement grout and polyurethane. The requirements for slab stabilization are strength and the ability to flow into or expand to fill small voids. Colloidal mixing equipment is necessary to use the pozzolan-cement grouts. The contractor must place the grout using a positive-displacement injection pump or a non-pulsing progressive cavity pump. A drill is also necessary but it must produce a clean hole with no surface spalling or breakouts. The injection devices must include a grout packer capable of sealing the hole. The injection device must also have a return hose or a fast-control reverse switch, in case workers detect slab movement on the uplift gauge. The uplift beam helps to monitor the slab deflection and has to have sensitive dial gauges.^[37][38]

Joint Sealing[link]

Also called joint and crack repair, this method’s purpose is to minimize infiltration of surface water and incompressible material into the joint system. Joint sealants are also used to reduce dowel bar corrosion in Concrete Pavement Restoration (CPR) techniques. Successful resealing consists of old sealant removal, shaping and cleaning the reservoir, installing the backer rod and installing the sealant. Sawing, manual removal, plowing and cutting are methods used to remove the old sealant. Saws are used to shape the reservoir. When cleaning the reservoir, no dust, dirt or traces of old sealant should remain. Thus, it is recommended to water wash, sand-blast and then air blow to remove any sand, dirt or dust. The backer rod installation requires a double-wheeled, steel roller to insert the rod to the desired depth. After inserting the backer rod, the sealant is placed into the joint. There are various materials to choose for this method including hot pour bituminous liquid, silicone and preformed compression seals.

^{[37][39][40][41]}

Safety considerations[link]

Pedestrian crossing, line markings and street furniture.

Careful design and construction of roads can increase Road traffic safety and reduce the harm (deaths, injuries, and property damage) on the highway system from traffic collisions.

On neighborhood roads traffic calming, safety barriers, pedestrian crossings and cycle lanes can all protect pedestrians and cyclists.

Lane markers in some countries and states are marked with Cat's eyes or Botts dots, bright reflectors that do not fade like paint. Botts dots are not used where it is icy in the winter, because frost and snowplows can break the glue that holds them to the road, although they can be embedded in short, shallow trenches carved in the roadway, as is done in the mountainous regions of California.

For major roads risk can be reduced by providing limited access from properties and local roads, grade separated junctions and median dividers between opposite-direction traffic to reduce likelihood of head-on collisions.

The placement of energy attenuation devices (e.g. guardrails, wide grassy areas, sand barrels) is also common. Some road fixtures such as road signs and fire hydrants are designed to collapse on impact. Light poles are designed to break at the base rather than violently stop a car that hits them. Highway authorities may also remove larger trees from the immediate vicinity of the road.

Environmental performance[link]

Air pollution along Pasadena Highway in Los Angeles, United States

Careful design and construction of a road can reduce any negative environmental impacts.

Water management systems can be used to reduce the effect of pollutants from roads.^{[citation needed]} Rainwater and snowmelt running off of roads tends to pick up gasoline, motor oil, heavy metals, trash and other pollutants and result in Water pollution. Road runoff is a major source of nickel, copper, zinc, cadmium, lead and polycyclic aromatic hydrocarbons (PAHs), which are created as combustion byproducts of gasoline and other fossil fuels.^[42] De-icing chemicals and sand can run off into roadsides, contaminate groundwater and pollute surface waters;^[43] and road salts can be toxic to sensitive plants and animals.^[44] Sand applied to icy roads can be ground up by traffic into fine particulates and contribute to air pollution. Sand can alter stream bed environments, causing stress for the plants and animals that live there.^{[citation needed]}

Roads are a chief source of environmental noise generation. In the early 1970s it was recognized that design of roads can be conducted to influence and minimize noise generation.^[45] Noise barriers are used to reduce Noise pollution, in particular where roads are located close to built-up areas. Regulations can restrict the use of Engine braking.

Motor vehicle emissions contribute air pollution. Concentrations of air pollutants and adverse respiratory health effects are greater near the road than at some distance away from the road.^[46] Road dust kicked up by vehicles may trigger allergic reactions.^[47]

Terminology[link]

The A22(T) with line markings near Summer Hill, East Sussex, England, United Kingdom

Road with guard rails in Kaluga Oblast, Russia

Road with traffic signs in the outskirts of Bern, Switzerland

Highway 401, a route with a collector / express setup.

The wide Coastal Road in the Philippines now called the Manila Cavite Expressway

Road in the Jujuy Province Argentina

• Alignment - the route of the road, defined as a series of horizontal tangents and curves.
• Adverse camber - where a road slopes towards the outside of a bend, increasing the likelihood that vehicles travelling at speed will skid or topple. Usually only a temporary situation during road maintenance.
• All-weather road - Unpaved road that is constructed of a material that does not create mud during rainfall.
• Banked turn
• Camber or Crown - the slope of the road surface downwards away from the centre of the road, so that surface water can flow freely to the edge of the carriageway, or on bends angling of the surface to lean traffic 'into the bend' reducing the chance of a skid.
• Cant - superelevation
• Cross slope The slope of the pavement, expressed as units of rise per unit of run, or as a percentage.
• Grade - longitudinal slope
• Belisha Beacon - an orange globe, lit at night, used to highlight a pedestrian crossing.
• Bollard - Rigid posts that can be arranged in a line to close a road or path to vehicles above a certain width
• Byway - Highway over which the public have a right to travel for vehicular and other kinds of traffic, but is used mainly as a footpath or bridleway
• Bypass Road that avoids or "bypasses" a built-up area, town, or village
• Bottleneck - Section of a road with a carrying capacity substantially below that of other sections of the same road
• Botts' dots - Non-reflective raised pavement marker used on roads
• Cat's eye - reflective raised pavement marker used on roads
• Central reservation - On dual carriageway roads, including controlled-access highways, divided highways and many limited-access roads, the central reservation (British English), median (North American English), median strip (North American English and Australian English), neutral ground [Louisiana English] or central nature strip (Australian English) - Area that separates opposing lanes of traffic
• Chicane - Sequence of tight serpentine curves (usually an S-shape curve or a bus stop)
• Chipseal - Road surface composed of a thin layer of crushed stone 'chips' and asphalt emulsion. It seals the surface and protects it from weather, but provides no structural strength. It is cheaper than asphalt concrete or concrete. In the U.S. it is usually only used on low volume rural roads
• Corniche - Road on the side of a cliff or mountain, with the ground rising on one side and falling away on the other
• Curb (kerb) - A raised edge at the side of the roadway.
• Curb extension - (also kerb extension, bulb-out, nib, elephant ear, curb bulge and blister) Traffic calming measure, intended to slow the speed of traffic and increase driver awareness, particularly in built-up and residential neighborhoods.
• Drainage gradient
• Farm-to-market road - a state road or county road that connects rural or agricultural areas to market towns.
• Fork - (literally "fork in the road") Type of intersection where a road splits
• Green lane - (UK) Unsurfaced road, may be so infrequently used that vegetation colonises freely, hence 'green'. Many green lanes are ancient routes that have existed for millennia.
• Guide rail - Prevents vehicles from veering off the road into oncoming traffic, crashing against solid objects or falling from a road. Also called a guard rail or traffic barrier.
• Gutter (UK) - a drainage channel usually at the edge of the road or along a median.
• Interstate Highway System (United States) - System of Interstate and Defense Highways
• Layby (Pullout, pull-off) - A paved area beside a main road where cars can stop temporarily to let another car pass.
• Loose chippings - the hazard of stone chippings that have come loose
• Median - On dual carriageway roads, including controlled-access highways, divided highways and many limited-access roads, the central reservation (British English), median (North American English), median strip (North American English and Australian English), neutral ground [Louisiana English] or central nature strip (Australian English) - Area that separates opposing lanes of traffic
• Mountain pass - A relatively low level route through a range of mountains
• Milestone - One of a series of numbered markers placed along a road, often at regular intervals, showing the distance to destinations.
• National Highway - Road built and maintained by a national authority.
• Pavement - The road regarded as a geoconstruction. In the UK the term is road surface and the pavement is a pedestrian walkway alongside the road.
• Pedestrian crossing - Designated point on a road where road marking or other means helps pedestrians cross safely
• Pelican crossing - (officially Pelicon crossing) UK a PEdestrian LIght CONtrolled crossing.
• Private highway - Highway owned and operated for profit by private industry
• Private road - Road owned and maintained by a private individual, organization, or company rather than by a government
• Profile - the vertical alignment of a road, expressed as a series of grades, connected by parabolic curves.
• Public space - Place where anyone has a right to come without being excluded because of economic or social conditions
• Ranch road - U.S. road that connects rural and agricultural areas to market towns
• Road number - Often assigned to identify a stretch of public roads— often dependent on the type of road, with numbers differentiating between interstates, motorways, arterial thoroughfares, etc.
• Road-traffic safety - Process to reduce the harm (deaths, injuries, and property damage) that result from vehicle crashes on public roads
• Roadworks - Part or all of the road is occupied for work or maintenance
• Roughness - Deviations from a true planar pavement surface, which affects vehicle suspension deflection, dynamic loading, ride quality, surface drainage and winter operations. Roughness have wavelengths ranging from 500 mm up to some 40 m. The upper limit may be as high as 350 m when considering motion sickness aspects; motion sickness is generated by motion with down to 0.1 Hz frequency; in an ambulance car driving 35 m/s (126 km/h), waves with up to 350 m will excite motion sickness.
• Roundabout UK a road junction where typically three or more roads are joined by a circular section of road. Traffic 'on the roundabout' has priority over traffic on approach roads, unless indicated otherwise. In countrys where traffic drives on the left the roundabout is travelled in a clockwise direction. Also known as an island in parts of the UK.
• Shoulder (also hard shoulder) - A clear, level area to the side of the roadway available for stopping if needed.
• State highway - Road numbered by the state, falling below numbered national highways (like U.S. Routes) in the hierarchy or a road maintained by the state, including nationally-numbered highways
• Traffic - Pedestrians, ridden or herded animals, vehicles, bicycles, and other conveyances using any road for purposes of travel. ^[48].
• Texture (roads) - Deviations from a true planar pavement surface, which affects the interaction between road and tire. Microtexture have wavelengths below 0.5 mm, Macrotexture below 50 mm and Megatexture below 500 mm.
• Traffic calming - Set of strategies used by urban planners and traffic engineers to slow down or reduce motor vehicle traffic, thereby improving safety for pedestrians and bicyclists and improving the environment for residents
• Traffic island - UK a small raised area used to help define the traffic flow, which may also act as a refuge for pedestrians crossing the carriageway or a location for signs, barriers or lights—a synonym for roundabout in some parts of the UK
• Traffic light - Also known as a traffic signal, stop light, stop-and-go lights—a signaling device at a road intersection, pedestrian crossing, or other location that assigns right of way to different approaches to an intersection
• Zebra crossing (UK) - a pedestrian crossing marked by black and white stripes on the carriageway

Regulation[link]

Right- and left-hand traffic[link]

Traffic flows on the right or on the left side of the road depending on the country.^[49] In countries where traffic flows on the right, traffic signs are mostly on the right side of the road, roundabouts and traffic circles go counter-clockwise/anti-clockwise, and pedestrians crossing a two-way road should watch out for traffic from the left first.^[50] In countries where traffic flows on the left, the reverse is true.

About 33% of the world by population drive on the left, and 67% keep right. By road distances, about 28% drive on the left, and 72% on the right,^[51] even though originally most traffic drove on the left worldwide.^[52]

Economics[link]

A city street in Mumbai, India with left-hand traffic.

Transport economics is used to understand both the relationship between the transport system and the wider economy and the complex network effects when there are multiple paths and competing modes for both personal and freight (road/rail/air/ferry) and where Induced demand can result in increased on decreased transport levels when road provision is increased by building new roads or decreased (for example California State Route 480). Roads are generally built and maintained by the public sector using taxation although implementation may be through private contractors).^[53][54] or occasionally using road tolls.^[55]

Public-private partnerships are a way for our communities to address the rising cost by injecting private funds into our infrastructure. There are four main ones:^[56]

• design/build
• design/build/operate/maintain
• design/build/finance/operate
• build/own/operate

Economics and society depend heavily on efficient roads. In the European Union (EU) 44% of all goods are moved by trucks over roads and 85% of all persons are transported by cars, buses or coaches on roads.^[57] The term was also commonly used to refer to roadsteads, waterways that lent themselves to use by shipping.

Construction costs[link]

According to the New York State Thruway Authority,^[58] some sample per-mile costs to construct multi-lane roads in several US northeastern states were:

• Connecticut Turnpike — $3,449,000 per mile
• New Jersey Turnpike — $2,200,000 per mile
• Pennsylvania Turnpike (Delaware Extension) — $1,970,000 per mile
• Northern Indiana Toll Road — $1,790,000 per mile
• Garden State Parkway — $1,720,000 per mile
• Massachusetts Turnpike — $1,600,000 per mile
• Thruway, New York to Pennsylvania Line — $1,547,000 per mile
• Ohio Turnpike — $1,352,000 per mile
• Pennsylvania Turnpike (early construction) — $736,000 per mile

Statistics[link]

The United States has the largest network of roads of any country with 4,050,717 miles (6,518,997 km) as of 2009.^[59] The People's Republic of China is second with 3,583,715 kilometres (2,226,817 mi) of road (2007) See List of countries by road network size. The Republic of India has the third largest road system in the world with 3,383,344 kilometres (2,102,312 mi) (2002). When looking only at expressways the National Trunk Highway System (NTHS) in People's Republic of China has a total length of 45,000 kilometres (28,000 mi) at the end of 2006, and 60,300 km at the end of 2008, second only to the United States with 90,000 kilometres (56,000 mi) in 2005.^[60][61]

Many human settlements are not reachable by road alone. Road vehicles must be carried by boat or ferry to islands, and some locations are intentionally car-free. Even on the mainland, some settlements have no roads connecting with the main continental network, due to natural obstacles like mountains or wetlands, remoteness, or general expense. Unpaved roads or lack of roads are more common in developing countries, though even large cities like Iquitos in Peru and Juneau, Alaska in the United States are disconnected.

See also[link]

References[link]