Rush-hour yesterday morning on the Capital Beltway was one of those nightmares that sends even the most artful commuter to work seething.

On the Beltway's northwest quadrant, where the Cabin John Bridge connects Montgomery and Fairfax counties, rubberneckers searching for wreckage from a fatal truck crash Tuesday slowed traffic to a crawl most of the day. A few motorists were even spotted parking and walking toward the scene with cameras in hand to record the disaster.

Earlier, a tractor trailer carrying a load of steel rods went out of control at the south point of the Beltway on the Maryland approach to the Woodrow Wilson Memorial Bridge into Virginia. The truck flipped over, blocking four westbound lanes from the 5 a.m. accident through the morning rush hour.

At its worst, traffic was stalled for miles in both direction from the Wilson bridge - six miles back on the Beltway's westbound lanes to Branch Avenue in Prince George's County and for a mile or two on numerous roads feeding into the Beltway from the District and southern Prince George's. Even on the opposite side of the highway, which was not blocked by the wreck, cars were backed up a mile into Virginia.

However, galling, tieups from accidents, sighteers and normal rush hour congestion are increasingly routine in a Beltway commuter's day.

From the air, the view displays regular and predictable patterns. WTOP traffic reporter Steve Thompson sees them daily from his Cessna 1950: standing two-mile tieups caused by the sheer crush of traffic at Georgia, Connecticut and Wisconsin avenues and the Beltway, the standard slowdowns on the Wilson bridge and the rush hour chaos at the I-66 - Virginia beltway intersection.

"Some backups happen, believe it or not, only on sunny days, sometimes for a half mile when the sun hits dirty windshields and the drivers can't see. There really are some neat traffic patterns from the sky," Thompson said.

Each morning, for example, he observes the predictable mile-long lineup of cars as they leave I-66 for the Beltway in Virginia. In the afternoons, both directions of the Beltway stack up as cars leave for I-66. Here the situation is always worse on sunny days, according to Thompson, because "they come around the ramp and bang, there's the sun on their dirty windshields which they haven't washed since the last snowstrom."

Such situations are normal, Thompson says. Yesterday was not.

Around the Cabin John Bridge, the rubberneckers stalled traffic for a half-mile throughout the day. A trucker was killed Tuesday when his tanker jacknifed on the slick bridge and dropped 60 feet to the Maryland bank of the Potomac River.

"Someone would come along in the fast lane, slow down and try to look over the bridge," said Maryland State Trooper William Corun. "It just takes one car to back up traffic."

Near the Wilson bridge, police aided by commercial radio traffic reports tried to divert traffic before the six-mile jam. But even the cagiest Beltway commuters caught between exits couldn't escape to their alternate routes. "Some places, they were just stuck there for two hours," said D.C. Police Officer C. A. Miller who watched it all from the air.