The government has decided to reveal the official gas mileage estimates of all vehicles from next year and include a driving resistance test in the individual testing procedures of carmakers, the Ministry of Knowledge Economy said Tuesday.

The ministry unveiled new toughened regulations to better control the discrepancy in the official and actual fuel economy of vehicles marketed here amid confusion following Hyundai Motor Group’s mileage overstatement scandal in the U.S. and Canada.

The government has revealed the car models and ordered corrective measures only when the difference in their official ratings and the actual amount of gas used is bigger than 5 percent.

The post-launch inspection has also been conducted only on 3-4 percent of the vehicles subject to the test largely due to tight budget constraints.

In Korea, no adjustment has been made in the stated mileage of vehicles for decades.

Under the new regulations, however, the allowable margin of error will be reduced to 3 percent ― the same level as in the U.S., where official ratings show the highest accuracy of 90-95 percent in reflecting the actual gas mileage.

The number of tested vehicles will increase to cover 10 percent of the total.

The government also decided to adopt a driving resistance test that measures the time it takes for a car running 130 kilometers per hour to stop completely.

“We are considering carrying out a revision to the related law in the first half of next year. Given the preparation period, the new regulations are expected to be implemented in the second half,” said a ministry official.

Officials from Korean and foreign carmakers said they feel some pressure about the renewed attention to mileage estimates.

“But the issue is not targeting specific companies but the whole industry. We are closely watching the impact,” said an industry source, declining to be identified.

Companies are also preparing for the introduction of a new mileage rating system next year that would lower the official fuel economy by 10-20 percent on average from those measured under the existing system.

By Lee Ji-yoon (jylee@heraldcorp.com)