Ford has stiffened the Escape SUV to improve its performance in frontal crash tests, but the small sport utility vehicle still lags its competition, the US insurance group that conducted the tests reportedly said on Sunday.

According to Reuters, the Escape, one of the top-selling small SUVs in the United States, improved its rating to "acceptable" from "marginal" in crash tests done by the Insurance Institute for Highway Safety - the group crashed four vehicles into a deformable barrier at 40 miles per hour (60km/h) in its latest safety tests, with 40% of the vehicle's front end hitting the barrier.

The Volvo S40 sedan, the BMW 5 series sedan and new Nissan Titan full-size pickup truck all earned "good" ratings in the tests and the institute's "best pick" designation for frontal crash protection, the report noted.

"The Escape has a few problems, but we still think it's 'acceptable,'" IIHS chief operating officer Adrian Lund told Reuters, adding: "I'm sure Ford, when they get to the major redesign of that vehicle, it will be a 'good' vehicle for frontal."

Competitive models such as Honda's CR-V, the Mitsubishi Outlander and Saturn Vue all earned "good" ratings in past frontal crash tests conducted by the IIHS, which is funded by insurance companies, Reuters added.

The IIHS reportedly said that, in the Escape's crash test, there was moderate intrusion in the foot area of the vehicle, raising the likelihood of injuries to the lower leg and foot in an actual crash, while Lund reportedly said there was also the possibility of serious neck injury due to the seat belt and air bag not performing as well as they should.

"From our perspective, we see that the Escape is showing an improvement in this test, and we're pleased," Ford spokeswoman Kristen Kinley told Reuters.

Reuters noted that, when the IIHS tested the Escape in 2001, results were disappointing. Lund reportedly said the head of the crash test dummy struck the steering wheel through the air bag, and there was considerable intrusion in the foot area.

Ford recently gave the Escape line a minor revision, slightly revamping the interior and adding an automatic transmission option for the smaller 2.3-litre four cylinder engine.

It also withdrew the Maverick-badged export versions from sale in the UK but they continue in other right-hand drive markets such as Australia and New Zealand.