Although these roads may experience greater severity than most roads to due higher speeds in the event of a crash, the probability of a crash is reduced by removing interactions (crossing, passing, slower and opposing traffic), and crash severity is reduced by removing massive, fixed objects or surrounding them with energy attenuation devices (e.g. guardrails, wide grassy areas, sand barrels). These mechanisms deliver lower fatalities per vehicle-kilometer of travel than other roadways, as documented in the following table.

Killed per 1 Billion Veh·km

km/h

Country

Killed per 1 Road Travel (mph)

Motorwa

Billion Veh·km by Motorwa

y

(Motorway(Non-MotorwayMotorway y 2003

AADT

s in s in 2003) Speed 2003) Limit

5.9 9.9 3.0 1.4 4.0 3.8 7.4 4.0 2.1 8.1 2.5 2.8 2.0 5.2

13.4 34.3 11.9 8.3 12.8 12.4 11.0 11.9 11.7 18.7 9.9 11.8 9.3 10.7

30,077 25,714 29,454 22,780 31,979 48,710 26,730 26,152 66,734 15,643 24,183 43,641 85,536 39,634

23% 11% 25% 10% 21% 31% 4% 9% 41% 19% 21% 33% 23% 24%

130 (80) 130 (80) 130 (80) 120 (75) 130 (80) none

(130 (80) advisory) 120 (75) 100 (60) 120 (75) 130 (80) 110 (70) 120 (75) 110 (70) 120 (75)

Austria Czech Republic Denmark Finland France Germany Ireland Japan Netherlands

Slovenia Sweden Switzerland United Kingdom United States

definition: AADT - average annual daily traffic.

Motorways are far more expensive and space-consumptive to build than ordinary roads, so are only used as principal arterial routes. In developed nations, motorways bear a significant portion of motorized travel; for example, the United Kingdom's 3533 km of motorways represented less than 1.5% of the United Kingdom's roadways in 2003, but carry 23% of road traffic.

The proportion of traffic borne by motorways is a significant safety factor. For example, even though the United Kingdom had a higher fatality rates on both motorways and non-motorways than Finland, both nations shared the same overall fatality rate in 2003. This result was due to the United Kingdom's higher proportion of motorway travel.

The improved safety and fuel economy of motorways are common justifications for building more motorways. However, the planned capacity of motorways is often exceeded in a shorter timeframe than initially planned, due to the under estimation of the extent of the suppressed demand for road travel. In developing nations, there is significant public debate on the desirability of continued investment in motorways. Motorways around the world are subject to a broad range of speed limits. Recent experiments with variable speed limits based on automatic measurements of traffic density have delivered both improvements in traffic flow and reduced collision rates, based on principles of turbulent flow analysis.[citation needed]

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. This change of policy applies only to barriers in the central reserve of high speed roads and not to verge side barriers. Other routes will continue to use steel barriers. Pavement design

Poor pavement construction can lead to safety problems. If too much asphalt or bitumenous binder is used in asphalt concrete, the binder can 'bleed' or flush' to the surface, leaving a very smooth surface that provides little traction when wet. Certain kinds of stone aggregate become very smooth or polished under the constant wearing action of vehicle tires, again leading to poor wet-weather traction. Either of these problems can increase wet-weather crashes by increasing braking distances or contributing to loss of control. If the pavement is insufficiently sloped or poorly

drained, standing water on the surface can also lead to wet-weather crashes due to hydroplaning. Vehicle safety features

Safety can be improved by reducing the chances of a driver making an error, or by designing vehicles to reduce the severity of crashes that do occur. Most industrialized countries have comprehensive requirements and specifications for safety-related vehicle devices, systems, design, and construction. These may include:

?

Passenger restraints such as seat belts — often in conjunction with laws requiring their use — and airbags

? Crash avoidance equipment such as lights and reflectors

? ?

Driver assistance systems such as Electronic Stability Control

Crash survivability design including fire-retardant interior materials, standards for fuel system integrity, and the use of safety glass

Sobriety detectors: These interlocks prevent the ignition key from working if the driver breathes into one and it detects significant quantities of alcohol. They have been used by some commercial transport companies, or suggested for use with persistent drink-driving offenders on a voluntary basis[14]

?

Countermeasures directed at drivers

Safety can be improved by methods that encourage safe behavior, or reduce the chances of driver error. Some of these include:

? ?

Compulsory training and licensing,

Restrictions on driving while drunk or impaired by drugs. ? Restrictions on mobile phone use while on the move.

Compulsory insurance to compensate victims.

? Restrictions on commercial vehicle driver hours, and fitting of tachographs.

? ?

Conventional and automated enforcement of traffic laws, including red-light running cameras and photo-radar.

Policies for novice drivers

Reasons suggested for young and inexperienced drivers being more likely to be in an accident include inexperience combined with over-confidence, peer pressure, a desire to show off, and incomplete neurological development.[15] It has been noticed that more of these types of serious collision occur at night, when the car has multiple

occupants and when seat belt use is less.[16] This has led to some insurance companies and legislatures proposing:

? ?

a \curfew\

an experienced supervisor to chaperone the less experienced driver ? forbidding the carrying of passengers

zero alcohol tolerance

? raising the standards required for driving instructors and improving the driving

?

test

vehicle restrictions (e.g. restricting access to 'high performance' vehicles) ? a sign placed on the back of the vehicle (an N- or P-Plate) to notify other

?

drivers of a novice driver

? encouraging good behaviour in the post-test period

Some countries or states have already implemented some of these ideas. This increased risk for the young is known to the insurance companies, and premiums sometimes reflect that; however, very high premiums for young drivers do not seem to have had a significant impact on the crash statistics.

Some of these interventions have been opposed by car manufacturers (see Unsafe at Any Speed) or by drivers, or by academics who believe that because of the risk compensation effect some of these measures may actually reduce road safety overall. Employers currently escape, for the most part, the chain of responsibility for their employees' driving on company business. Truck drivers, especially self-employed ones, can be given unrealistic deadlines to meet. There are moves to bring driving for work (both commercial vehicles and, more controversially, private cars driven on company business) under the umbrella of workplace safety legislation. These are strongly resisted as they would place a far greater burden on employers and

employees alike: penalties for industrial safety infractions are typically much greater than for negligent motor vehicle use. Other road users

Pedestrians and Cyclists are among the most vulnerable road users[17], and in some countries constitute over half of all road deaths. Interventions aimed at improving safety of non-motorised users:

? ?

segregated facilities such as cycle lanes, underpasses and overbridges physical separation of segregated facilities

? ?

limiting pedestrian access to highways

bicycle helmet promotion and compulsion

? traffic awareness campaigns such as the \

documented by Hillman et al.

?

pedestrian crossings, which are seen as restricting the number of points at which a road may be crossed and often requiring detours. traffic calming and speed humps

? ?

reduced urban speed limits

? rigorous speed limit enforcement by automated means such as speed cameras Road safety advertising

Road traffic authorities around the world have mounted advertising campaigns to convince drivers to operate vehicles safely. Examples include:

Speeding. No one thinks big of you. (New South Wales, Australia, 2007) ? Road Safety is no Accident World Health Organization

?

Criticisms

Non-motorised lobby

Pedestrians' advocates, environmental groups and related organisations such as RoadPeace have been strongly critical of what they see as moves to solve the problem of danger posed to vulnerable road users by motor traffic through increasing

restrictions on vulnerable road users, an approach which they believe both blames the victim and fails to address the problem at source. This is discussed in detail by Dr Robert Davis in the book Death on the Streets: Cars and the mythology of road safety, and the core problem is also addressed in books by Professor John Adams, Mayer Hillman and others.

It is argued by some that the problem of road safety is largely being stated in the wrong terms because most road safety measures are designed to increase the safety of drivers, but many road traffic casualties are not drivers (in the UK only 40% of casualties are drivers), and those measures which increase driver safety may, perversely, increase the risk to these others, through risk compensation.