The increased use of monitoring services is helping lower the rate of vehicles on roads with open recalls.
One out of every five registered vehicles has an open recall, but the rate is slowly decreasing, according to CarFax.
"Open recalls are a critical safety issue that can impact everyone on the road," said Dick Raines, Carfax president, in a statement. "It's imperative that car buyers, sellers and especially owners stay informed about recalls and take action on them to maintain the safety of their vehicles and our roads."
The company released annual research findings that show more than 52 million vehicles with a recall remain unfixed. California (6.3 million), Texas (5.5 million), Florida (3.2 million), Pennsylvania (2.2 million) and New York (2.1 million) have the most vehicles with open recalls.
For the second year in a row, light trucks and minivans are the vehicles most likely to have unfixed recalls.
Overall, open recalls have declined over the last two years, down from 63 million in 2017 and 57 million in 2018, according to Carfax.
In addition to monitoring services, checks for open recalls during state vehicle inspections have helped consumers fix critical safety issues.
While taking any vehicle off the road to be fixed can be an inconvenience, recall repairs often are completed in only an hour or two, and most take less than a day, CarFax reported.