Factors contributing to road crashes, resulting deaths and severity of injuries
Road Infrastructure and Management
Intelligent road design and management play a critical role in road safety. Well-constructed infrastructure includes effective traffic management systems; traffic calming measures such as traffic circles, speed bumps, lane narrowings and speed cameras; segregation of slow from high speed vehicles; barriers or medians to separate two-way traffic; improvement of road surfaces and removal of roadside hazards and black spots; effective road furniture such as guardrails, signage and lighting; and wider lanes and shoulders for high-speed roads. Fast-moving traffic should be diverted from rather than traverse highly populated areas and be connected by spurs or other similar means.
Effective measures must also be put in place for the safety of pedestrians and cyclists. These include sidewalk infrastructure, safe crossing points, dedicated lanes for pedestrians and cyclists, crosswalks and crosswalk enhancements, pedestrian overpasses, raised islands, increased crossing times and signalized intersections and the designation of car-free zones.
Safe vehicles are a key factor in protecting drivers, passengers and all other road users. Manufacturing vehicles that meet important safety standards greatly reduces road crash fatalities and the severity of injury when crashes occur. These include requiring vehicle manufacturers to meet front and side impact regulations, incorporate electronic stability control to prevent over-steering and ensure airbags and seat belts are fitted in all vehicles. Vehicle safety can be further enhanced through additional features including antilock brakes and LATCH child safety seat system as well as with newer accident avoidance and driver assistance technologies such as backup cameras, blind spot detection, forward collision and lane departure warnings and autonomous emergency braking. Cars also have been redesigned to include features that protect pedestrians in the event of a collision.
Enactment and Enforcement of Traffic Laws
The establishment or amendment of evidence-based traffic laws and their rigorous enforcement will lead to a dramatic reduction in road fatalities and injuries. Laws are needed that govern the risk factors including speeding, drink-driving, and the use of helmets, seat belts and child restraints. Effective laws, penalties and enforcement are needed at the national, state and local levels.
Road User Behaviors
Road crash data indicate that speeding; driving, walking and cycling under the influence of alcohol or drugs; failure to use seat belts, child restraints, helmets and reflective gear; distracted driving and walking; and irresponsible pedestrian and cyclist behaviors are all risk factors that contribute to road crashes.
Speeding. According to the World Health Organization (WHO), an increase in average speed is directly related both to the likelihood of a crash occurring and to the severity of the consequences of the crash. In high income countries, speed contributes to about 30% of road deaths, and in many low- and middle-income countries, speed is the main factor in about half of all road crashes. Speed limits should be appropriate to the function of each road. It is recommended that there be a speed limit of 30 km/hr on roads with a high concentration of pedestrians. The use of speed and red light cameras also may be effective deterrents for speeding.
The Influence of Alcohol or Drugs. Drink- and drug-driving increases the risk of a crash that results in death or serious injuries. For example, the risk of a road crash increases significantly when a driver’s blood alcohol concentration (BAC) is ≥ 0.04 g/dl. Ideally, all road users should refrain from using alcohol or drugs as they impair judgment and increase reflex time. Currently, WHO recommends a BAC limit for the general population of ≤ 0.05 g/dl but a limit of ≤ 0.02 g/dl for young/novice drivers. Sobriety checkpoints and random breath testing also may help to discourage drink-driving.
Failure to Use Seat Belts, Child Restraints, and Helmets. The proper use of seat belts, child restraints and helmets dramatically reduce road crash deaths and injuries. According to WHO, wearing a seat belt reduces the risk of death among drivers and front seat occupants by 45-50% and death and serious injuries to rear occupants by 25%. It is imperative that national seat belt laws applying to both front and rear passengers be implemented.
National child restraint laws based on age, weight and height or a combination of these factors, when enforced, can lead to a 60% reduction in deaths. Laws should also be put into place restricting children under a certain age and height from sitting in the front seat in vehicles. Children should sit in booster seats when they have outgrown the child safety seat. According to WHO booster seats should be utilized by children weighing from 15kg-25kg.
Mandating and enforcing the use of standardized helmets that are properly fastened for motorcyclists can lead to a 42% reduction in the risk of fatal injuries and a 69% reduction in the risk of head injuries, according to WHO. The laws should apply to both motorcyclists and their passengers.
Distracted Driving and Walking
There are numerous types of distractions, including fatigue, which can lead to road crashes. The distraction caused by speaking or texting on mobile phones is a growing concern for road safety. According to WHO, drivers using mobile phones are approximately 4 times more likely to be involved in a crash than drivers not using a mobile phone. Using a phone while driving slows reaction times (notably braking and reacting to traffic signals) and makes it difficult to keep in the correct lane and to keep the correct following distances. Hands-free phones are not much safer than hand-held phones. Other common distractions include adjusting settings and technology while driving, reaching for objects, focusing on children in the back seat and talking with others in the vehicle.
Fatigue-related crashes are most common in very early morning hours and mid-afternoon. Risk also increases when driving long distances or on monotonous roads or when driving during normal sleeping hours. The chance of serious or fatal injuries increases because of slower driver response time or dozing off at the wheel. Drivers can avoid fatigue by stopping at least every 2 hours on long trips; getting out of the vehicle regularly and stretching and walking when possible; and switching drivers and resting when not driving.
Distracted pedestrians are also a growing concern. Walking while texting or talking on a cell phone causes pedestrians to lose focus and fail to respond to changing traffic lights or vehicles entering a crosswalk or making a turn at an intersection. Pedestrians should remain alert while walking and make eye contact with drivers to ensure their safety.
Risky Pedestrian, Bicyclist and Motorcyclist Behavior
Pedestrians, cyclists, and riders of motorized 2- and 3-wheelers and their passengers are collectively known as “vulnerable road users” and account for half of all road traffic deaths around the world, according to WHO.
Pedestrians should use designated pedestrian crossings, be alert for vehicles turning into their path, walk on sidewalks rather than in the streets, in the absence of sidewalks walk facing oncoming traffic, and wear white or bright colors by day and reflective gear at night along with a flashlight. They must never assume that because they have the right away in a pedestrian crossing that it is automatically safe to cross.
Bicyclists should wear buckled regulation helmets even when not required by law. Like pedestrians, they should also wear white or bright colors by day and reflective gear at night. Bicycles should be maintained regularly and be equipped with headlights, tail lights, front and rear wheel reflectors and other safety equipment. Riders should utilize bike lanes whenever available and should be particularly aware of drivers’ blind spots and parked vehicle doors being opened unexpectedly. It is important for cyclists to maintain safe riding speeds in conformity with the law and appropriate to conditions.
Motorcyclists and their passengers should wear buckled regulation helmets and motorcycle body armor to protect themselves in case of a crash. Motorcyclists should inspect their bikes before each ride, observe all traffic safety laws, be visible by driving with headlights even during the day, wear reflective or bright colored clothing and always use turn signals and hand signals. It is important that motorcyclists maintain safe speeds, stay at a safe distance from other motorcycles and vehicles, refrain from weaving in and out of traffic and watch for road hazards.
Comprehensive trauma systems save lives by addressing the multidisciplinary needs of victims of road crashes before, during and after injuries occur. A single alert system, locally integrated and regionally monitored, triggers an immediate response from first responders through triage, pre-hospital treatment and appropriate hospital care. Post-crash components address the continuation of medical services, such as rehabilitation, mental health and legal services; trauma care training; data collection, monitoring and evaluation, as well as prevention at both individual and population levels.
Studies have consistently demonstrated that high-income countries with comprehensive trauma systems dramatically reduce preventable deaths from road crashes by at least 50% over lower and middle-income countries. The global impact in lives that would be saved with rapid access to regionalized, organized response with trauma trained and properly equipped pre-hospital and hospital services is convincing.
Effective post-crash response also demands policy and legislation to protect the injured and their families and to ensure legal compensation. Laws are necessary to guarantee adequate crash investigation and mandate appropriate liability insurance for drivers. Bereaved family members also need support to deal with their emotional and economic loss and the legal issues with which they are confronted. Governmental and non-governmental organizations must be put into place to inform victims and their families of their rights and the resources that are available to them.