Over a third of all drivers killed weren't wearing their seatbelts
A third of drivers and passengers killed in fatal road crashes this year were not wearing a seatbelt.
The Road Safety Authority (RSA) said that 15 of 41 drivers, and four of 15 passengers were not wearing a safety belt.
The RSA also warned of a spike in deaths among older road users.
RSA chief executive Moyagh Murdock said that complacency could be setting in among older drivers, coupled with some having "a bit of mid-life crisis", which resulted in speeding. Further research was needed, she said.
The RSA and gardai warned that unless drivers changed their behaviour as many as 100 more people will die before the end of the year.
New figures show that 92 people have died between January and July this year, a drop of 21 on the same period in 2014, but that non-seatbelt wearing was a major source of concern.
A provisional review of road fatalities for the first seven months of the year shows that 87 collisions have occurred.
"Should our record continue as per July with 20 deaths per month, as many as 100 more people could lose their lives by year end," Ms Murdock said.
"Of particular concern is the fact that, of the 57 drivers and passengers killed to date in 2015, 15 drivers and four passengers were reported as not wearing their seatbelts."
The review of fatalities from January to July, 2015, finds that road deaths have declined by 19pc compared to last year (92 compared to 113) with reductions in all road-user groups.
Up to July 31, 41 drivers, 16 passengers, 18 pedestrians, 12 motorcyclists and five cyclists have been killed.
There has been a rise in the numbers of people aged 16-25, which is up from 19 to 23. The sharpest drop is among road users aged 15 or younger, which fell 11, followed by vehicle passengers, which dropped by nine.
While April had the lowest number of monthly fatalities since November, 2012 - with eight fatalities - July was the most dangerous month - with 20 lives lost.
Transport Minister Paschal Donohoe said that, while any reduction in fatalities was welcomed, "we cannot and must not become complacent".
"I'm particularly shocked by the statistics around seatbelt use," he added. "To see that as a factor in 37pc of drivers who tragically lost their lives is a real reminder to us to refocus our efforts and remind us to use seatbelts.
"We need to promote the message of seatbelts. A core message to all road users is that personal responsibility plays a crucial role in reducing fatalities."
Superintendent Con O'Donoghue from the Garda National Traffic Bureau added that bad decisions cost lives.
Some 3,666 motorists have been detected driving while intoxicated, another 88,409 caught speeding, and 4,715 stopped for not wearing a seatbelt so far this year, he added. Another 13,560 were caught using a mobile phone.
Nine have died on the roads in August, bringing the total to date to 101, down 22 on last year.