Describe the epidemiology and prevention of road traffic injuries.

Road Traffic Injuries

• The preferred term is road traffic crash or injury, precisely because "accident" implies an unforeseeable act of fate and discourages prevention
• The INDIAN pattern — a high proportion of vulnerable road users: pedestrians, cyclists and particularly two-wheeler riders, who together account for the majority of deaths
• This contrasts with high-income countries, where car occupants predominate, and it determines that Indian countermeasures must protect people outside vehicles
• Deaths fall disproportionately on young men of working age, so the economic and family consequences are severe
• The HADDON matrix is the standard analytical framework and should be used to structure the answer — it crosses three phases (pre-crash, crash and post-crash) with three factors (human, vehicle and environment), giving nine cells
• Pre-crash (preventing the crash) — human: speeding, drink-driving, fatigue, mobile phone use, inexperience, poor vision; vehicle: brakes, tyres, lights, maintenance; environment: road design, junctions, lighting, signage, weather, mixed traffic
• Crash (reducing injury during the crash) — human: helmet and seat belt use, child restraints; vehicle: crashworthiness, airbags, crumple zones; environment: crash barriers, breakaway poles, absence of roadside hazards
• Post-crash (reducing the consequences) — human: first aid and bystander action; vehicle: fire risk, ease of extrication; environment: emergency medical services, trauma care, rehabilitation
• The major risk factors with the best evidence for intervention:
• Speed — the single most important, since it affects both the risk of a crash and the severity of the injury; a small reduction in average speed produces a disproportionately large reduction in deaths, and pedestrian survival falls very steeply above about 30 km/h
• Alcohol — addressed by legal blood alcohol limits with random breath testing
• Helmets — which substantially reduce head injury and death among two-wheeler riders, and are the highest-value single measure in India given the predominance of two-wheelers; pillion riders must be included, and the strap must be fastened, since an unfastened helmet leaves at impact
• Seat belts and child restraints, including for rear-seat occupants, whose use remains very low in India
• Visibility — reflective clothing and vehicle lighting
• The intervention hierarchy, in descending order of effectiveness — engineering (road and vehicle design), enforcement of legislation, and education
• Education alone is the weakest, and engineering the strongest, because it protects people without requiring them to change their behaviour — which is the same principle as making the healthy choice the easy choice
• The safe system approach accepts that humans will make errors, and designs roads and vehicles so that those errors do not result in death
• Post-crash care — the golden hour; a national emergency number and ambulance service; trained bystanders and first responders; organised trauma care with designated centres; and rehabilitation
• The good samaritan protections are important in India, since fear of police questioning, legal liability and hospital detention deterred bystanders from helping the injured; guidelines and law now protect those who assist
• The relevant legislation is the motor vehicles (amendment) act 2019, which substantially increased penalties, strengthened Good Samaritan protection and provided for cashless treatment during the golden hour
• They are crashes, not accidents, since the word accident implies fate and discourages prevention
• Engineering beats enforcement beats education, because engineering protects without requiring behaviour to change
• Use the Haddon matrix to structure the answer, crossing three phases with three factors to give nine cells
• Speed affects both crash risk and injury severity, which is why it is the single most important factor
• Pedestrian survival falls steeply above thirty kilometres an hour, which justifies urban speed limits
• Vulnerable road users predominate in India, so countermeasures must protect people outside vehicles
• Helmets are the highest-value single measure here, given how many Indians travel by two-wheeler
• Fasten the strap and include the pillion, since an unfastened helmet simply leaves the head at impact
• Rear seat belt use remains very low, though the benefit is comparable to that in the front
• The safe system accepts that humans err, and designs so that error does not become death
• Good Samaritan protection matters in India, since fear of police and liability deterred bystanders from helping
• The golden hour determines survival, which makes prehospital care and trauma systems as important as prevention
• Deaths fall on young men of working age, so the family and economic consequences exceed the mortality figures