The number of those killed in car accidents on highways surged last month, police said Thursday, suggesting that the decrease in sobriety testing conducted in the month due to the Middle East respiratory syndrome outbreak appears to have affected the rise.

The National Police Agency said 25 people were killed on Korean roads in June, a 50 percent increase from 18 deaths a year ago.

The number of overall casualties during the first half of this year, however, decreased, with 109 people having been killed in highway car accidents - down 12.1 percent from last year’s 124, the statistics showed.

Police said the decline stemmed from less frequent investigations into those who drove under influence due to widespread fear of MERS, a virus that is spread through sneezes, coughs and droplets of saliva and mucus.

The law enforcement caught 266 drunk drivers in June, a 38.3 percent decrease compared to 165 in the same period of 2014.