Road traffic safety

For example, the chances of survival for an unprotected pedestrian hit by a vehicle diminish rapidly at speeds greater than 30 km/h, whereas for a properly restrained motor vehicle occupant the critical impact speed is 50 km/h (for side impact crashes) and 70 km/h (for head-on crashes).As sustainable solutions for classes of road safety have not been identified, particularly low-traffic rural and remote roads, a hierarchy of control should be applied, similar to classifications used to improve occupational safety and health.

The third level is about reducing the crash risk which involves applying the road-design standards and guidelines (such as from AASHTO), improving driver behavior and enforcement.

[7] The standard measures used in assessing road safety interventions are fatalities and killed-or-seriously-injured (KSI) rates, usually expressed per billion (109) passenger kilometres.

For occupants, Joksch (1993) found the probability of death for drivers in multi-vehicle collisions increased as the fourth power of impact speed (often referred to by the mathematical term δv ("delta V"), meaning change in velocity).

This enabled the Swedish Road Administration to identify the KSI risk curves using actual crash-reconstruction data which led to the human tolerances for serious injury and death referenced above.

Study conducted in Finland revealed that the fatality risk is increased most when a collision type is either pedestrian or meeting[clarification needed] of the vehicles.

Important people traversing crowded streets and alleys in ancient Rome (famous for its Roman roads) deployed minions to clear the way for their litters or (if allowed) carts and chariots.

In the 19th century the advent of powered vehicles inspired British road-safety law to impose speed limits and to require a person on foot carrying a red flag warning of the arrival of a frightening noisy mechanical contrivance.

These new patterns, which are recommended for laying out neighbourhoods, are based on analyses of collision data of large regional districts and over extended periods.

Most roads are cambered (crowned), that is, made so that they have rounded surfaces, to reduce standing water and ice, primarily to prevent frost damage but also increasing traction in poor weather.

Certain kinds of stone aggregate become very smooth or polished under the constant wearing action of vehicle tyres, again leading to poor wet-weather traction.

If the pavement is insufficiently sloped or poorly drained, standing water on the surface can also lead to wet-weather crashes due to hydroplaning.

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.

Road hazards and intersections in some areas are now usually marked several times, roughly five, twenty, and sixty seconds in advance so that drivers are less likely to attempt violent manoeuvres.

Most road signs and pavement marking materials are retro-reflective, incorporating small glass spheres[32] or prisms to more efficiently reflect light from vehicle headlights back to the driver's eyes.

Passive traffic safety measures sought to avoid influencing the behavior of drivers while giving automobiles maximum convenience.

[41] Recent complete street policies seek to create design-oriented traffic safety improvements which actively slow drivers down by narrowing roadways while better accommodating pedestrians and cyclists.

Successful cycling schemes by contrast avoid frequent stops even if some additional distance is involved, because cyclists expend more energy when starting off.

were potentially self-defeating because "every nonrestrictive safety measure, however admirable in itself, is treated by the drivers as an opportunity for more speeding, so that the net amount of danger is increased and the latter state is worse than the first.

[48] Reported results indicate that the 'shared space' approach leads to significantly reduced traffic speeds, the virtual elimination of road casualties, and a reduction in congestion.

With effect from January 2005 and based primarily on safety grounds, the UK's Highways Agency's policy is that all new motorway schemes are to use high containment concrete step barriers in the central reserve.

All existing motorways will introduce concrete barriers into the central reserve as part of ongoing upgrades and through replacement as and when these systems have reached the end of their useful life.

[55] The higher fatality risk is due in part to the lack of crash protection (unlike in enclosed vehicles such as cars), combined with the high speeds motorcycles typically travel at.

In 2008, The National Highway Traffic Safety Administration (NHTSA) estimated the helmets are 37 percent effective in saving lives of motorcyclists involved in crashes.

Some jurisdictions, such as the US states Virginia and Maryland, have implemented specific regulations such as the prohibiting mobile phone use by, and limiting the number of passengers accompanying, young and inexperienced drivers.

While government has primary responsibility for providing safe roads, the challenges of development and equity require that all segments of society engage and contribute, including the private sector.

[66] Safer roads also benefit business by improving employee health and safety, by protecting assets, reducing productivity losses and healthcare costs, and enhancing the efficiency and effectiveness of supply chains.

Other key facts according to the WHO report are:[76] It is estimated that motor vehicle collisions caused the death of around 60 million people during the 20th century, around the same number of World War II casualties.

[77] As the comparatively poor improvements in pedestrian safety have become a concern at OECD level, the Joint Transport Research Centre of OECD and the International Transport Forum (JTRC) convened an international expert group and published a report entitled ”Pedestrian Safety, Urban Space and Health in 2012”.

The GM President James Roche was later forced to appear before a United States Senate subcommittee, and to apologize to Nader for the company's campaign of harassment and intimidation.

Sidewalks , curbs and traffic signals in Hagerstown, Maryland , United States
Speed limits in different areas; here unusually with only a "recommended" limit ( Richtgeschwindigkeit ) of 130 km/h on the Autobahn in Germany
DRIP [ Note 1 ] variable message sign guiding traffic on the Dutch A13 motorway
Vehicles experiencing a breakdown or an emergency can stop in the emergency lane ; these lanes may themselves present risks to traffic.
Sacrifices to the Modern Moloch , a 1923 cartoon published in St. Louis Star , criticizing the apparent acceptance by society of increasing automobile-related fatalities
Guardrails save a vehicle from a long fall c. 1920. Guard rails were only sometimes effective at the time. It was not until the 1960s that safety testing ensured adequate protection, and even then only for vehicles of a limited weight-class.
Pedestrian crossing , line markings and street furniture
A curb extension at a mid-block crosswalk
A traffic circle applied to a four-way intersection as a means of improving its safety. This device, with a proven record of collision reductions and traffic flow improvement, turns the cross-intersection into four virtual three-way intersections.
Utrecht has specially painted bicycle-only lanes.
Safe from traffic for cycling along a fully segregated Fietspad , properly designed cycling infrastructure in Amsterdam
A shared space in Brighton (UK)
Guard rail on road in Kaluga Oblast ( Russia )
The Pan-American Highway with central median and no freestanding obstructions
The Autostrada A20 ( Italy ) with large central median
Simulated crashes using crash test dummies can help improve automobile design.
The Dutch Reach - Use far hand on handle when opening to avoid dooring cyclists or injuries to exiting drivers and passengers.
Annual traffic deaths sign over I-95 in Georgia , US, indicating more than three deaths per day
According to Eurostat , there is almost a linear proportion between the total number of passenger-km driven by car and road fatalities.
Car fatalities per pax-km vs. car usage per pax-day; in Europe. It seems, at least in these European countries, that car fatalities per person-km have no strong correlation with massification of car usage. The average car usage in these countries is around 30km per person-day with varying number of fatalities ratios. These differences might be related with different cultural approaches to traffic codes, or more safety measures implemented on such countries.
According to Eurostat and European Railway Agency , in European railway mode of transport, there is a fatality risk for passengers and occupants 28 times lower compared with car usage. Based on data by EU-27 member nations, 2008–2010. [ 68 ] [ 69 ]