There were nine road accidents that killed three people every 10 minutes in 2015, according to new national data, an increase of nine per cent over four years.

Road accidents killed 148,000 people in 2015 compared to 136,000 in 2011, according to the Accidental Deaths and Suicides in India report released by the National Crime Records Bureau (NCRB). Road accidents accounted for 83 per cent of all traffic-related deaths in India and 43 per cent of all accidental deaths in 2015.

Other traffic-related deaths were from railway accidents (15 per cent) and accidents at railway crossings (two per cent).

There were 464,000 road accidents in 2015, an increase of three per cent from 2014, when there were 450,000 road accidents.

While Tamil Nadu (69,059), Karnataka (44,011) and Maharashtra (42,250) reported the most road accidents, Uttar Pradesh reported the highest number of deaths in road accidents (18,407).

The road transport sector contributes to 4.8 per cent of the country's gross domestic product (GDP), but India loses 1-3 per cent of GDP due to road accidents, according to a 2007 report of the road transport working group of the erstwhile Planning Commission for the XIth Plan.

Despite a national road safety strategy and laws on speed limits, wearing helmets and seat belts and drunk-driving, the World Health Organisation rates India's enforcement as 3 out of 10 on speed limits, 4 out of 10 on wearing motorcycle helmet, 4 out of 10 on drunk-driving and 4 out of 10 on wearing seat belts.

Two-wheeler accidents accounted for 29 per cent of all fatal road accidents in 2015, claiming 45,540 lives, followed by trucks (19 per cent), which killed 28,910 people and cars (12 per cent), which killed 18,506 people.

Tamil Nadu (3,668) and Maharashtra (3,146) reported the largest number of people killed in two-wheeler accidents, while Uttar Pradesh had reported the largest number of lives lost due to truck accidents (5,720) and car accidents (2,135).

More pedestrians were killed in Maharashtra (1,256) than any other state, accounting for 17 per cent of pedestrian deaths.

Although national highways account for only 1.51 per cent of India's road length, they accounted for 28 per cent of road accidents and 33 per cent of road-mishap deaths nationwide in 2015.

State highways, three per cent of India's road length, contributed to 25 per cent of road accidents and 28 per cent of deaths due to road mishaps.

Over-speeding was responsible for 41 per cent of deaths in road accidents, while careless or dangerous driving claimed 32 per cent of death in road accidents. Poor weather (four per cent) and mechanical defects (three per cent) in motor vehicles were other causes for deaths in road accidents.

Tamil Nadu and Maharashtra had the most number of casualties due to over-speeding, with 15 per cent and 12 per cent of cases, respectively.

Uttar Pradesh had the largest number of deaths due to careless/dangerous driving (17 per cent), followed by Maharashtra (nine per cent).

Chennai accounted for nine per cent of all road accidents in 53 cities, followed by Delhi (nine per cent) and Bengaluru (six per cent). Delhi (eight per cent) and Jaipur (five per cent) had the largest number of deaths in road accidents.