Speed limits on road traffic, as used in most countries, set the legal maximum speed at which vehicles may travel on a given stretch of road. Speed limits are generally indicated on a traffic sign reflecting the maximum permitted speed, expressed as kilometres per hour (km/h) or miles per hour (mph) or both. Speed limits are commonly set by the legislative bodies of national or provincial governments and enforced by national or regional police and judicial authorities. Speed limits may also be variable, or in some places nonexistent, such as on most of the Autobahnen in Germany.
Traffic signs or road signs are signs erected at the side of or above roads to give instructions or provide information to road users. The earliest signs were simple wooden or stone milestones. Later, signs with directional arms were introduced, for example the fingerposts in the United Kingdom and their wooden counterparts in Saxony.
The expressways of Singapore are special roads that allow motorists to travel quickly from one urban area to another. Construction of the system was authorized when construction of the Pan Island Expressway began in 1962. All of them are dual carriageways with grade-separated access. They usually have three to four lanes in each direction, although there are two-lane carriageways at many expressway intersections and five-lane carriageways in some places. There are currently ten expressways and studies about the feasibility of more are ongoing.
Motorway Incident Detection and Automatic Signalling, usually abbreviated to MIDAS, is a UK distributed network of traffic sensors, mainly inductive loops, which are designed to alert the local regional control centre (RCC) to traffic flow and average speeds, and set variable message signs and advisory speed limits with little human intervention. Companies such as RAC, TomTom and Google use this traffic flow data via halogens reporting systems.
The Schuylkill Expressway, locally known as "the Schuylkill", is a freeway through southern Montgomery County and Philadelphia. It is the easternmost segment of Interstate 76 (I-76) in the U.S. state of Pennsylvania. It extends from the Valley Forge interchange of the Pennsylvania Turnpike in King of Prussia, paralleling its namesake Schuylkill River for most of the route, southeast to the Walt Whitman Bridge over the Delaware River in South Philadelphia. It serves as the primary corridor into Philadelphia from points west. Maintenance and planning for most of the highway are administered through Pennsylvania Department of Transportation (PennDOT) District 6, with the Delaware River Port Authority (DRPA) maintaining the approach to the Walt Whitman Bridge.
Road signs in the United Kingdom and in its associated Crown dependencies and overseas territories conform broadly to European design norms, though a number of signs are unique: direction signs omit European route numbers, and road signs generally use the imperial system of units, unlike the rest of Europe. Signs in Wales and parts of Scotland are bilingual.
A gantry is a traffic sign assembly in which signs are mounted or railway signals are supported on an overhead support. They also often contain the apparatus for traffic monitoring systems and cameras, or open road tolling systems.
Road signs in Malaysia are standardised road signs similar to those used in Europe but with certain distinctions. Until the early 1980s, Malaysia closely practice in road sign design, with diamond-shaped warning signs and circular restrictive signs to regulate traffic. Signs usually use the Transport Heavy font on non-tolled roads and highways. Tolled expressways signs use a font specially designed for the Malaysian Highway Authority (LLM) which is LLM Lettering. It has two type of typefaces, LLM Narrow and LLM Normal. Older road signs used the FHWA Series fonts typeface also used in the United States, Canada, and Australia.
Road signs in Singapore closely follow those laid down in the traffic sign regulations used in the United Kingdom, although a number of changes over the years have introduced some slight deviations that suit local road conditions. Road signs in Singapore conform to the local Highway Code under the authority of Singapore Traffic Police.
Active traffic management is a method of increasing peak capacity and smoothing traffic flows on busy major highways. Techniques include variable speed limits, hard-shoulder running and ramp-metering controlled by overhead variable message signs. It has been implemented in several countries, including Germany, the United Kingdom, Canada and the United States.
A radar speed sign or speed feedback sign is an interactive sign comprising a speed-measuring device and a message sign generally constructed of a series of LEDs, which displays vehicle speed of approaching motorists. The purpose of radar speed signs is to slow cars down by making drivers aware when they are driving at speeds above the posted limits. They are used as a traffic calming device in addition to or instead of physical devices such as speed bumps and rumble strips.
An advisory speed limit is a speed recommendation by a governing body, used when it may be non-obvious to the driver that the safe speed is below the legal speed. It is a posting which either approximates the Basic Speed Law or rule or is based on a maximum g-force exerted at a specific speed. Advisory speed limits are often set in areas with many pedestrians, such as in city centres and outside schools, and on difficult stretches of roads, such as on tight corners or through roadworks. While travelling above the advisory speed limit is not illegal per se, it may be negligence per se and liability for any collisions that occur as a result of traveling above the limit can be placed partially or entirely on the person exceeding the advisory speed limit.
Road signs in Italy conform to the general pattern of those used in most other European countries, with the notable exception that the background of motorway (autostrada) signs is green and those for 'normal' roads is blue. They are regulated by the Codice della Strada and by the Regolamento di Attuazione del Codice della Strada in conformity with the 1968 Vienna Convention on Road Signs and Signals.
In the United States, road signs are, for the most part, standardized by federal regulations, most notably in the Manual on Uniform Traffic Control Devices (MUTCD) and its companion volume the Standard Highway Signs (SHS).
The road signs of the Kingdom of the Netherlands, as well as Suriname, are regulated in the Reglement verkeersregels en verkeerstekens 1990, commonly abbreviated as RVV 1990. While most previous signage, from the RVV 1966 (Dutch) remained legal and official, they have been updated / replaced. Some aren't official anymore and have lost legal validity, but most surviving old signs remained valid.
IRIS is an open-source Advanced Traffic Management System (ATMS) software project developed by the Minnesota Department of Transportation. It is used by transportation agencies to monitor and manage interstate and highway traffic. IRIS uses the GPL license.
Road traffic control devices are markers, signs and signal devices used to inform, guide and control traffic, including pedestrians, motor vehicle drivers and bicyclists. These devices are usually placed adjacent, over or along the highways, roads, traffic facilities and other public areas that require traffic control.
Road signs in New Zealand are similar to those set by the Vienna Convention on Road Signs and Signals. While New Zealand is not a signatory to the convention, its road signs are generally close in shape and function. New Zealand uses yellow diamond-shaped signs for warnings in common with Australia, the Americas, Ireland, Japan and Thailand. Speed limit signs are a red circle with a white background and the limitation in black, and are in kilometres per hour. There are also some signs unique to New Zealand. Road signs in New Zealand are controlled by NZ Transport Agency Waka Kotahi and are prescribed in the Land Transport Rule: Traffic Control Devices 2004 and set out in the Traffic Control Devices (TCD) Manual.
Speed limits in the United States vary depending on jurisdiction. Rural freeway speed limits of 70 to 80 mph are common in the Western United States, while such highways are typically posted at 65 or 70 mph in the Eastern United States. States may also set separate speed limits for trucks and night travel along with minimum speed limits. The highest speed limit in the country is 85 mph (137 km/h), which is posted on a single stretch of tollway in exurban areas outside Austin, Texas. The lowest maximum speed limit in the country is 30 miles per hour (48 km/h) in American Samoa.
Terminology related to road transport—the transport of passengers or goods on paved routes between places—is diverse, with variation between dialects of English. There may also be regional differences within a single country, and some terms differ based on the side of the road traffic drives on. This glossary is an alphabetical listing of road transport terms.
