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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.
With railways, a head-on collision occurs most often on a single line railway. This usually means that at least one of the trains has 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". [3] As time progressed and signalling became more standardized, such accidents 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 accidents happening in rural America where farming and cornfields were common. The first known usage of the term was in the mid-19th century.
The distance required for a train to stop is usually greater than the distance that can be seen before the next blind curve, which is why signals and safeworking systems are so important.
Note: if the collision occurs at a station or junction, or trains are travelling in the same direction, then the collision is not a pure head-on collision
With shipping, there are two main factors influencing the chance of a head-on collision. Firstly, even with radar and radio, it is difficult to tell what course the opposing ships are following. Secondly, big ships have so much momentum that it is very hard to change course at the last moment.
 | The examples and perspective in this section may not represent a worldwide view of the subject.(February 2016) |
Head-on collisions are an often fatal type of road traffic collision. The NHTSA defines a head-on collision thusly:
Refers To A Collision Where The Front End Of One Vehicle Collides With The Front End Of Another Vehicle While The Two Vehicles Are Traveling In Opposite Directions. [7]
In Canada, in 2017, 6,293 vehicles and 8,891 persons were involved in head-on collision, injuring 5,222 persons and killing 377 other. [8]
U.S. statistics show that in 2005, head-on crashes were only two per cent of all crashes, yet accounted for ten per cent of U.S. fatal crashes. A common misconception is that this over-representation is because the relative velocity of vehicles travelling in opposite directions is high. While it is true (via Galilean relativity) that a head-on crash between two vehicles traveling at 50 mph is equivalent to a moving vehicle running into a stationary one at 100 mph, it is clear from basic Newtonian Physics that if the stationary vehicle is replaced with a solid wall or other stationary near-immovable object such as a bridge abutment, then the equivalent collision is one in which the moving vehicle is only traveling at 50 mph., [9] except for the case of a lighter car colliding with a heavier one. The television show MythBusters performed a demonstration of this effect in a 2010 show. [10]
In France, in the years 2017 and 2018, 2563 and 2556 head-on collisions (collision frontales) outside built-up area outside motorways killed 536 and 545 people respectively. [11] They represent about 16% of all the fatalities including the ones on motorways and within built-up area.
In Quebec, head-on collisions are involved in eight per cent of work-related issues, but this figure rises to 23 per cent when the vehicles involved are in a rural zone where the maximum speed is greater than 70 km/h (43 mph). [12]
Head-on collisions, sideswipes, and run-off-road crashes all belong to a category of crashes called lane-departure or road-departure crashes. This is because they have similar causes, if different consequences. The driver of a vehicle fails to stay centered in their lane, and either leaves the roadway, or crosses the centerline, possibly resulting in a head-on or sideswipe collision, or, if the vehicle avoids oncoming traffic, a run-off-road crash on the far side of the road.
Preventive measures include traffic signs and road surface markings to help guide drivers through curves, as well as separating opposing lanes of traffic with wide central reservation (or median) and median barriers to prevent crossover incidents. Median barriers are physical barriers between the lanes of traffic, such as concrete barriers or cable barriers. These are actually roadside hazards in their own right, but on high speed roads, the severity of a collision with a median barrier is usually lower than the severity of a head-on crash.
The European Road Assessment Programme's Road Protection Score (RPS [ permanent dead link ]) is based on a schedule of detailed road design elements that correspond to each of the four main crash types, including head-on collisions. The Head-on Crash element of the RPS measures how well traffic lanes are separated. Motorways generally have crash protection features in harmony with the high speeds allowed. The Star Rating results show that motorways generally score well with a typical 4-star rating even though their permitted speeds are the highest on the network. But results from Star Rating research in Britain, Germany, the Netherlands and Sweden have shown that there is a pressing need to find better median (central reservation), run-off and junction protection at reasonable cost on single carriageway roads.
Another form of head-on crash is the wrong-way entry crash, where a driver on a surface road turns onto an off-ramp from a motorway or freeway, instead of the on-ramp. They can also happen on divided arterials if a driver turns into the wrong side of the road. Considerable importance is placed on designing ramp terminals and intersections to prevent these incidents. This often takes to form of special signage at freeway off-ramps to discourage drivers from going the wrong way. Section 2B.41 of the Manual on Uniform Traffic Control Devices describes how such signs should be placed on American highways.
Neither vehicle in a head-on collision need be a "car"; the Puisseguin road crash was between a truck and a coach.
Sideswipe collisions are where the sides of two vehicles travelling in the same or opposite directions touch. They differ from head-on collisions only in that one vehicle impacts the side of the other vehicle rather than the front. Severity is usually lower than a head-on collision, since it tends to be a glancing blow rather than a direct impact. However, loss of control of either vehicle can have unpredictable effects and secondary crashes can dramatically increase the expected crash severity.
A high-occupancy vehicle lane is a restricted traffic lane reserved for the exclusive use of vehicles with a driver and at least one passenger, including carpools, vanpools, and transit buses. These restrictions may be only imposed during peak travel times or may apply at all times. There are different types of lanes: temporary or permanent lanes with concrete barriers, two-directional or reversible lanes, and exclusive, concurrent, or contraflow lanes working in peak periods.
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.
Road traffic safety refers to the methods and measures used to prevent road users from being killed or seriously injured. Typical road users include pedestrians, cyclists, motorists, vehicle passengers, and passengers of on-road public transport.
A dual carriageway (BrE) or a divided highway (AmE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are designed to higher standards with controlled access are generally classed as motorways, freeways, etc., rather than dual carriageways.
In road transport, a lane is part of a roadway that is designated to be used by a single line of vehicles to control and guide drivers and reduce traffic conflicts. Most public roads (highways) have at least two lanes, one for traffic in each direction, separated by lane markings. On multilane roadways and busier two-lane roads, lanes are designated with road surface markings. Major highways often have two multi-lane roadways separated by a median.
Rumble strips are a road safety feature to alert inattentive drivers of potential danger, by causing a tactile fuzzy vibration and audible rumbling transmitted through the wheels into the vehicle interior. A rumble strip is applied along the direction of travel following an edgeline or centerline, to alert drivers when they drift from their lane. Rumble strips may also be installed in a series across the direction of travel, to warn drivers of a stop or slowdown ahead, or of an approaching danger spot.
A passing lane, overtaking lane is a lane on a multi-lane highway or motorway closest to the median of the road used for passing vehicles in other lanes. Countries with right-hand traffic put the passing lane on the left; those with left-hand traffic put the passing lane on the right. Motorways typically have passing lanes along their entire length, but other roads might only have passing lanes for certain segments, depending on design specifications typically related to available space, funding, and traffic levels. A 2+1 road alternates the passing lane between directions every few kilometers/miles.
A side collision is a vehicle crash where the side of one or more vehicles is impacted. These crashes typically occur at intersections, in parking lots, and when two vehicles pass on a multi-lane roadway.
A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway, and expressway. Other similar terms include throughway or thruway and parkway. Some of these may be limited-access highways, although this term can also refer to a class of highways with somewhat less isolation from other traffic.
2+1 road is a specific category of three-lane road, consisting of two lanes in one direction and one lane in the other, alternating every few kilometres, and usually separated with a steel cable barrier. The second lane allows faster-moving traffic to overtake slower vehicles at regular intervals. Traditional roads of at least 10 metres (33 ft) width can be converted to 2+1 roads and reach near-motorway safety levels at a much lower cost than an actual conversion to motorway or dual carriageway.
Access management, also known as access control, when used in the context of traffic and traffic engineering, generally refers to the regulation of interchanges, intersections, driveways and median openings to a roadway. Its objectives are to enable access to land uses while maintaining roadway safety and mobility through controlling access location, design, spacing and operation. This is particularly important for major roadways intended to provide efficient service to through-traffic movements.
Traffic barriers keep vehicles within their roadway and prevent them from colliding with dangerous obstacles such as boulders, sign supports, trees, bridge abutments, buildings, walls, and large storm drains, or from traversing steep (non-recoverable) slopes or entering deep water. They are also installed within medians of divided highways to prevent errant vehicles from entering the opposing carriageway of traffic and help to reduce head-on collisions. Some of these barriers, designed to be struck from either side, are called median barriers. Traffic barriers can also be used to protect vulnerable areas like school yards, pedestrian zones, and fuel tanks from errant vehicles.
The Auckland Northern Motorway in the Auckland Region of New Zealand links Central Auckland and Warkworth in the former Rodney District via the Hibiscus Coast and North Shore. It is part of State Highway 1.
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 traffic collisions generally fall into one of five common types:
A roadway departure is a type of incident that occurs when a vehicle leaves the roadway. Such incidents can lead to a single-vehicle collision.
Road speed limits in the United Kingdom are used to define the maximum legal speed for vehicles using public roads in the UK.
The September 3, 1999, Ontario Highway 401 crash, was a multiple-vehicle collision that resulted from dense fog conditions on a section of Ontario Highway 401 between Windsor and Tilbury. There were 87 vehicles involved in the pile-up in both directions of the divided highway, killing eight people and injuring a further 45.
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.
Automated lane keeping systems (ALKS), also described as traffic jam chauffeurs, is an autonomous driving system that doesn't require driver supervision on motorways. ALKS is an international standard set out in UN-ECE regulation 157 and amounts to Level 3 vehicle automation. It is essentially a more robust combination of adaptive cruise control (ACC) and lane centering assist (LCA). When activated, it allows the driver to do non-driving tasks until alerted otherwise.
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