Ford Motor Co.'s ’02 Explorer will qualify — but just barely — for an acceptable 3-star rollover rating under contentious National Highway Traffic Safety Admin. guidelines.

Meanwhile, General Motors Corp. confirms its challenger to Explorer's title as most popular sport/utility vehicle — the recently launched ’02 Chevrolet TrailBlazer — scores better than its competitor.

NHTSA's rating yardstick, the “static stability factor” (SSF) is determined by dividing half a vehicle's track measurement by the height of its center of gravity. An SSF of 1.13 to 1.24 qualifies for a 3-star rating. This suggests a rollover risk between 20% and 30% — but only in the event of a single-vehicle crash.

The ratings “do not mean a vehicle will spontaneously roll over in your driveway,” a NHTSA spokesman says.

The new Explorer is wider than its predecessors by 2.4 ins. in front and 2.7 ins. at the rear. But Ford admits its 2-wheel drive (2WD) model has an SSF of just 1.13 — the bare minimum to achieve a 3-star rating. In its larger-track 4-wheel-drive (4WD) guise, it earns an SSF of 1.15.

That's a marked improvement over the 1.06 SSF that tagged ’01 Explorers — 4WD and 2WD — with a 2-star rating (an SSF of 1.05 to 1.12, and a rollover risk between 30% and 40%).

Chevy boasts that its 4WD TrailBlazer enjoys an SSF of 1.19, while its 2WD model hits 1.20.

NHTSA had earmarked 70 of the 2001 vehicles for rollover ratings, but when production ramped up for ’02 Explorer and TrailBlazer, the agency added them to its test list, citing “public interest.”