Crossing the Pacific: with California's ports unloading at a record pace, shippers find congestion relief arrives at night.(traffic congestion prevention at Port of Los Angeles and Port of Long Beach)

Barely into the 2006 peak import season from Asia, carriers and shippers that depend on Southern California's sprawling ports are crossing their fingers that epic congestion at the United States' most important import gateways is now only a distant memory.

Many major container liner companies and port watchers, including the National Retail Federation and consultants Global Insight, say operations at the ports of Los Angeles and Long Beach are smooth and should remain free of significant backups through the fall.

Some shippers aren't popping champagne corks just yet, particularly as they worry about congestion at inland transit points. But even the most cynical observers believe a major snarl-up is unlikely and many point to the lessons learned from the storied backups of 2004.

Some of those lessons have led shippers to seek out alternative gateways, spreading the goods and the risk across more ports. But maW experts credit a large share of the improvement to operating changes on Southern California's docks, and they call the year-old PierPass system one of the most effective new measures.

PierPass CEO Bruce Wargo says more than 2 million truck trips have been moved to the 6 p.m. to 3 a.m. off-peak weekday hours since the program began in July 2005, accounting for 40 percent of traffic.

Wargo describes PierPass as "wildly successful. The program …