|
Road Geometry
The geometric design of roads is the branch of highway engineering concerned with the positioning of the physical elements of the roadway according to standards and constraints. The basic objectives in geometric design are to optimize efficiency and safety while minimizing cost and environmental damage. Geometric design also affects an emerging fifth objective called "livability", which is defined as designing roads to foster broader community goals, including providing access to employment, schools, businesses and residences, accommodate a range of travel modes such as walking, bicycling, transit, and automobiles, and minimizing fuel use, emissions and environmental damage. Geometric roadway design can be broken into three main parts: alignment, profile, and cross-section. Combined, they provide a three-dimensional layout for a roadway. * The alignment is the route of the road, defined as a series of horizontal tangents and curves. * The profile is the vertical aspect of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autovia Olivar
Autovia was a short lived brand of British car from Coventry existing from 1935 to 1938 with production starting in January 1937.''The Times'', Wednesday, 22 September 1937; pg. 6; Issue 47796 The venture was ambitious and even included setting up a school for chauffeurs. The cars were expensive and it was a market sector well served by other companies. 44 cars were made. Large luxury cars The company was created by Riley (automobile), Riley as a subsidiary to produce large luxury cars and a new factory was built. A 2849 cc 90°V-8, triple camshaft engine was developed from a pair of 1½-litre Riley engine blocks and coupled to a Preselector gearbox, pre selector unit bought from Armstrong Siddeley. One car was fitted with a ZF 4 speed manual box, drive was to the rear wheels through a live axle with worm gear final drive. Three body types were advertised, a Sports saloon, a Special Saloon with extra leg room at the expense of boot space and a limousine mostly built by A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Runoff
Surface runoff (also known as overland flow or terrestrial runoff) is the unconfined flow of water over the ground surface, in contrast to ''channel runoff'' (or ''stream flow''). It occurs when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when the soil is #Saturation excess overland flow, saturated by water to its full capacity, and the rain arrives #Infiltration excess overland flow, more quickly than the soil can absorb it. Surface runoff often occurs because wikt:impervious#Adjective, impervious areas (such as roofs and Road surface, pavement) do not allow water to soak into the ground. Furthermore, runoff can occur either through natural or human-made processes. Surface runoff is a major component of the water cycle. It is the primary agent of Soil erosion#Rainfall and runoff, soil erosion by water. The land area producing runoff that drains to a common point is called a drainage basin. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assured Clear Distance Ahead
In legal terminology, the assured clear distance ahead (ACDA) is the distance ahead of any terrestrial locomotive device such as a land vehicle, typically an automobile, or watercraft, within which they should be able to bring the device to a halt. It is one of the most fundamental principles governing ordinary care and the duty of care for all methods of conveyance, and is frequently used to determine if a driver is in proper control and is a nearly universally implicit consideration in vehicular accident liability. The rule is a precautionary trivial burden required to avert the great probable gravity of precious life loss and momentous damage. Satisfying the ACDA rule is necessary but not sufficient to comply with the more generalized basic speed law, and accordingly, it may be used as both a layman's criterion and judicial test for courts to use in determining if a particular speed is negligent, but not to prove it is safe. As a spatial standard of care, it also serves as r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Braking Distance
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction. Background Most brakes commonly use friction between two surfaces pressed together to convert the kinetic energy of the moving object into heat, though other methods of energy conversion may be employed. For example, regenerative braking converts much of the energy to electrical energy, which may be stored for later use. Other methods convert kinetic energy into potential energy in such stored forms as pressurized air or pressurized oil. Eddy current brakes use magnetic fields to convert kinetic energy into electric current in the brake disc, fin, or rail, which is converted into heat. Still other braking methods even transform kinetic energy into different forms, for example by transferring the energy to a rotating flywheel. Brakes are generally a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eminent Domain
Eminent domain, also known as land acquisition, compulsory purchase, resumption, resumption/compulsory acquisition, or expropriation, is the compulsory acquisition of private property for public use. It does not include the power to take and transfer ownership of private property from one property owner to another private property owner without a valid public purpose. This power can be legislatively delegated by the state to municipalities, government subdivisions, or even to private persons or corporations, when they are authorized to exercise the functions of public character. The most common uses of property taken by eminent domain have been for roads, government buildings and public utility, public utilities. Many railroads were given the right of eminent domain to obtain land or easements in order to build and connect rail networks. In the mid-20th century, a new application of eminent domain was pioneered, in which the government could take the property and transfer it to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Right Turn On Red
Turn on red is a principle of law permitting vehicles at a traffic light showing a red signal to turn into the direction of traffic nearer to them (almost always after a complete stop, depending on the jurisdiction) when the way is clear, without having to wait for a green signal. North American traffic engineers first introduced this rule as a fuel savings measure in the 1970s, despite detrimental effects to the safety of pedestrians. Canada and the United States are some of few major countries where turning on red is generally allowed. Amid a push to reduce pedestrian fatalities and make cities safer for pedestrians and bicyclists, some American localities have in recent years implemented bans on turning on red. Turns Right on red The simplest version is commonly known as a right turn on red (or simply right on red) in countries that Right- and left-hand traffic, drive on the right side of the road, or a left turn on red in List of countries with left-hand traffic, countr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Right-of-way (transportation)
A right of way (also right-of-way) is a specific route that people, animals, vehicles, watercraft, or utility lines travel, or the legal status that gives them the right to do so. Rights-of-way in the physical sense include controlled-access highways, railroads, canals, hiking paths, bridle paths for horses, bicycle paths, the routes taken by high-voltage lines (also known as wayleave), utility tunnels, or simply the paved or unpaved local roads used by different types of traffic. The term ''highway'' is often used in legal contexts in the sense of "main way" to mean any public-use road or any public-use road or path. Some are restricted as to mode of use (for example, pedestrians only, pedestrians, horse and cycle riders, vehicles capable of a minimum speed). Rights-of-way in the legal sense (the right to pass through or to operate a transportation facility) can be created in a number of different ways. In some cases, a government, transportation company, or conservation n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boulevard Rule
The boulevard rule is a principle in United States traffic law which states that the driver of a vehicle entering a highway from a smaller road or entrance (called the ''unfavored driver'') must stop and yield the right of way to all highway traffic (the ''favored drivers''). The rule often comes into play in road accident cases, when a court must determine if a driver is negligent in causing a collision, due to his breach of the duty of care imposed by the rule on the unfavored driver. State laws Maryland is among the U.S. states which follow this rule, but not all states have similar provisions in statutes or case law. New YorkN.Y. Vehicle & Traffic Code § 1143 applies the rule to traffic entering public roads from private driveways or alleys, but not where public roads intersect. See also *Priority to the right Priority to the right is a right-of-way system in right-hand traffic, in which the driver of a vehicle is required to give way to vehicles approaching from the rig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
All-way Stop
An all-way stop – also known as a four-way stop (or three-way stop etc. as appropriate) – is a traffic management system which requires vehicles on all the approaches to a road intersection to stop at the intersection before proceeding through it. Designed for use at low traffic-volume locations, the arrangement is common in the United States, Canada, Mexico, South Africa, and Liberia, as well as in a number of, usually rural, locations in Australia where visibility on the junction approaches is particularly poor. The stop signs at such intersections may be supplemented with additional plates stating the number of approaches. Operation In most jurisdictions of the United States, the rules of the all-way stop are the same. A motorist approaching an all-way stop is always required to come to a full stop behind the crosswalk or stop line. Pedestrians always have the priority to cross the road, even if the crosswalk is not marked with surface markings. * If a driver arrives ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Head-on Collision
A head-on collision is a traffic collision where the front ends of two vehicles such as cars, trains, ships or planes hit each other when travelling in opposite directions, as opposed to a side collision or rear-end collision. Rail transport With railways, a head-on collision occurs most often on a Single track (rail), single line railway. This usually means that at least one of the trains has Signal passed at danger, passed a signal at danger, or that a signalman has made a major error. Head-on collisions may also occur at junctions, for similar reasons. In the early days of railroading in the United States, such collisions were quite common and gave to the rise of the term "Cornfield Meet". As time progressed and signalling became more standardized, such collisions became less frequent. Even so, the term still sees some usage in the industry. The origins of the term are not well known, but it is attributed to crashes happening in rural America where farming and co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Run-off-road Collision
A roadway departure (also called roadway excursion or run-off-road collision) is a type of incident that occurs when a vehicle leaves the roadway. Such incidents can lead to a single-vehicle collision. Causes and consequences Contributing factors can include: * loss of control due to excessive or inappropriate speed * distraction * misjudging a curve * attempting to avoid colliding with another road user or an animal. If the vehicle strikes a fixed object (an object that will move very little when struck, such as a tree, bridge structure or utility pole) or rolls over, the crash is likely to result in injuries or fatalities. US statistics for 2005 show that roadway departure crashes resulted in 31% of fatal crashes, but were only 16% of all crashes. Roadway departure collisions where the vehicle is sliding or spinning and runs broadside into a fixed obstacle are particularly dangerous since the vehicle doors and sides provide less protection to occupants than the front of the ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Design Speed
The design speed is a tool used to determine geometric features of a new road or street during road design. Contrary to the word's implication, the design speed of the road or street is not necessarily its vehicle speed limit or maximum safe speed; that can be higher or lower. Choosing a design speed means finding a balance between several interests which compete for priority, such as high vehicle speeds to allow drivers to travel to their destinations quickly versus low vehicle speeds for the safety of people outside the vehicle (such as pedestrians and cyclists), or quick movement of peak traffic ( traffic engineering) versus maximising the economic development potential of the street (urban planning). Geometric features The design speed chosen for a high-speed roadway is a major factor in choosing superelevation rates and radii of curves, sight distance, and the lengths of crest and sag vertical curves. Roads with higher design speeds require wider lanes, sweeping c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
