Tens of thousands of southern California motorists had mixed results today as they waited in service station lines on the first day of the odd-even gas allocation plan.

Supply and convenience varied widely from community to community and sometimes from station to station within the same neighborhood.

Lines at gas stations in the San Francisco Bay area, San Jose and San Diego were somewhat shorter.

The fuel crush has brought 12 Calirornia counties into the odd-even modified form of gas rationing. The system now covers at least 10 million of the state's 15 million drivers.

The gas crisis continues to produce rippling effects beyond the difficulty of purchasing a tank of gasoline. They include reports that:

Traffic on freeways in the central Los Angeles area has been reduced by almost 15 percent, according to California Department of Transportation figures.

Organized service station operators in California still plan a four-day shutdown from May 17 to May 20 to enforce demands for a bigger share of profits.

State Assembly Speaker Leo T. McCarthy, a San Francisco Democrat, saying that "millions of Californians are confused and angry," ordered a legislative investigation to see if the gasoline shortage is real or contrived.

A spot check by Times staffers indicated that:

Most service station operators and drivers seemed to observing the odd-even designation.

Although the emergency odd-even system signed by Gov. Edmund G. Brown Jr. requires it, very few attendants were checking gas gauges to make certain fuel tanks were half empty.

Generally, waiting motorists seemed calmer than before initiation of the fuel-sharing plan.

However, everything did not go smoothly on the first day of the odd-even plan.

Hundreds of motorists and service station dealers called a Los Angeles County information center to complain and ask for information.

Some complained that dealers were limiting the amount of gasoline they would sell to as little as five gallons, thus ignoring the law, which requires an operator to sell up to 20 gallons. CAPTION: Picture, Dozens of cars line up at Los Angeles gosoline station as odd-even rationing plan goes into effect.