AURORA, Ont. - Provincial police are blaming distracted driving, speeding, impaired driving and failure to buckle up for the majority of road deaths in Ontario this year.

The OPP says these are the "Big Four" in terms of contributing factors in 168 of the 216 road deaths investigated by the force so far in 2014.

As of this Sunday, speed was a factor in 51 of the 168 deaths and distracted driving was in second place with 45 deaths.

Lack of occupant restraint is in third place, causing 38 deaths, and impaired driving in fourth, with 34 road deaths.

The OPP notes that the four factors are also the leading causes of collision deaths throughout Canada.

To reduce road deaths, the provincial force is joining other police services across the country for Operation Impact, a national road safety enforcement and education campaign.