Even with historic levels of recalled vehicles in 2014, with General Motors Co. ignition switches and exploding Takata Corp. air bags leading to deaths, U.S. regulators say consumers don’t always get the message.

Defective cars only get repaired about two-thirds of the time. The National Highway Traffic Safety Administration and automakers including GM are meeting in Washington all day Tuesday to devise new ways to get the word out that when there’s a recall, motorists need to act.

In the wake of last year’s ignition-switch recall, GM said it studied the characteristics of customers who weren’t getting recall repairs. The company redesigned mailings with different imagery to convey the urgency of the repairs, added online outreach through YouTube and Yahoo! and offered loaner cars. Some dealers in Texas even offered tickets to the state fair as an incentive.

Even with all that effort, which made 98 percent of customers aware of the defect, repairs still went undone, Julie Heisel, GM’s director of customer relationship management, said at the symposium.

“Awareness doesn’t mean action,” she said.

On average, a third of repairs still aren’t complete within 18 months of a manufacturer issuing a recall. As cars change hands and automakers lose track, motorists often don’t know they are driving a car with a deadly defect.

“Recalls are only successful, and they only save lives, if they end up getting the cars fixed,” U.S. Transportation Secretary Anthony Foxx said.

Multiple Mailings

When GM evaluated what worked, customers often mentioned that it took multiple mailings and extra phone calls and assurances of loaner cars to get the deal done, Heisel said.

An estimated 46 million cars with unfixed recalls were on the road at the end of last year and as many as 5 million of those changed ownership in 2014, according to Carfax Inc.

The problem has grown as vehicle recalls in the U.S. surpassed the 60 million mark for the first time in a single year in 2014, double the previous annual record of 30.8 million set in 2004, according to an analysis of data on NHTSA’s website.

GM alone recalled about 27 million cars and trucks in the U.S. last year, a record for any single automaker. Defective GM ignition switches in small cars have been linked to at least 90 deaths and 163 injuries, according to statistics from Kenneth Feinberg, a lawyer hired by the automaker to administer a claims program.

Regulators also are investigating Takata air-bag inflators that may malfunction, deploying with so much force that the part breaks and hurls metal shrapnel at the car’s occupants. At least five fatalities in the U.S. and more than 100 injuries have been reported industrywide.

Nissan, Toyota

Ten automakers, including Nissan Motor Co., Honda Motor Co. and Toyota Motor Corp., since 2008 have recalled about 17 million vehicles with Takata air bags. Last year, five automakers upgraded recalls for drivers’ side air bags at NHTSA’s urging.

NHTSA is not without blame. In October, the agency botched an effort to inform the public about the potentially lethal air- bag defect, directing 8 million consumers to an inoperable website and leaving millions of others unsure as to whether their cars were even at risk.

For more than two days after telling motorists of the urgent need to check the government-run safercar.gov for information, the search function on the website was down.