Rearview Mirror

Drivers stuck in traffic along the 10 freeway can see the 215 Riverside Freeway interchange and layers of connector roads behind them in Riverside. (Richard Hartog / Los Angeles Times)

When Los Angeles traffic experts get depressed at the sorry state of the freeways, their minds sometimes drift to the improbable days of 1984, when the Olympic torch blazed through town and the city's sea of cars parted.

For more than a week, downtown and Westside freeways worked as their creators had intended, whisking drivers from place to place.

The respite from congestion was flickeringly brief, but many still ask: Can the experiment be repeated?

For the 16-day event, transportation agencies put aside turf wars. Employees carpooled or worked staggered hours or took vacations. Truckers shifted deliveries to off-hours. Construction projects were rescheduled. Arterial lanes were reserved for buses. Two-way streets became one-way streets.

"We had essentially no congestion," said David Roper, retired operations chief for the California Department of Transportation's Los Angeles division. "What was behind all this was the feeling 'I don't want to be the guy who screws up the Olympics.' "

It was "a real-world example," Roper said, "of how a few minor adjustments" can spur major improvements. Though overall traffic rose slightly, a 2% drop in the number of cars at rush hour kept traffic moving.

A similar thing happens on holidays that affect only government workers or on Jewish holidays such as Yom Kippur, when just a small percentage of drivers stay home but traffic speeds pick up nicely and rush hour lasts about half as long. And traffic has eased slightly in some places with the recent rise in gas prices.

It turns out that meager fractions, added or subtracted, can make the system scream or purr.

So if the answer to our traffic miseries seems so simple -- keeping a handful of wheels off the road -- how come it's so hard to do permanently?

Consider what happened in 1988, when Honolulu tried to thin rush-hour traffic by forcing half the city's public employees to arrive at work 45 minutes later for a month.

Congestion eased, but the affected workers complained of problems with ride-sharing, child care and meeting other obligations before and after work. In the end, the main beneficiaries were drivers who didn't have to shift their schedules.

Or consider what happened that same year, when the South Coast Air Quality Management District required about 9,000 big firms in the area to find ways to reduce solo car trips. The firms promoted carpooling, sold transit passes and provided on-site health clubs, cafeterias and cash machines.

The result? More people got to work by bike, bus, carpool and on foot.

But businesses chafed at what they considered an unfunded government mandate, and complaints grew with the early-1990s recession. So the program became voluntary and withered.

People say they want less traffic, but they don't want to be forced to alter their habits, planners say. And no one has found the key to getting them to change voluntarily.

The 1984 Olympics worked, traffic-wise, only because the changes required were temporary, according to a study by USC transportation expert Genevieve Giuliano.

As normal life reasserted itself, competing interests came back into play. Truckers had no incentive to work late without overtime. Workers wanted to return to their normal hours and ways of getting to work. Complaints by local merchants killed a pair of one-way streets linking the Coliseum to downtown, even though the shift had substantially increased flow.

Much of the time, when government declares war on congestion, it does so by laying track or pouring concrete. Lure people from their cars with improved mass transit, the thinking runs, or free up the roads by building more of them.

But despite massive investments in both strategies, Southern California traffic has worsened as newcomers have poured into the area and commutes have lengthened.