Two evenings in a California Traffic School. It's better than a day in court (or a blotch on your driving record), many motorists decide

TEACHER: ``What are you in for?'' Student: ``U-turn. Moorpark Avenue between Laurel Canyon and Whitsett.'' Teacher: ``That's mid-block in a business district - illegal.'' Student: ``But I thought it was residential - there's nothing but apartments and condos....'' Teacher: ``Apartments and condos qualify as business district in the state of California.'' Student: ``Oh!'' You hear a lot of ``Ohs!'' two nights a week at the Bruce Elkins Traffic School, one of hundreds of private but state-licensed mini-institutes set up for public correction and enlightenment in California.

Depending on your perspective, giving up two evenings from 6 to 10 p.m. might be called ``punitive'' as well. Either way, that's what 700,000 California drivers opted for last year instead of shelling out the $35 to $80 cost of moving violation tickets.

For the drivers, the rationale is not so much saving the cost of the ticket, but rather keeping the violation off their records where insurance companies could find it and raise the drivers' premiums. As the judge will explain to those motorists who appear in court, should you complete traffic school, no record of your infraction will be kept - except in a publicly off limits file at the Department of Motor Vehicles (DMV), to make sure you don't use the privilege more than once a year.

For the courts - since choosing traffic school waives a driver's right to a trial - it's a way to keep thousands off court dockets already swelling beyond capacity.

``We feel by giving drivers the option of going to traffic school instead of paying a ticket and getting a record, that there is a certain amount of reeducation going on, a reminder of some of the tricky things to know about driving,'' says Gina McGuiness, an official at the California DMV. ``There's no statistics saying those that go through are better drivers, but judges feel those that are reintroduced to traffic laws will become better drivers.''

``I thought it would be an utter waste of time, and pure punishment,'' said Peter Flaherty (not his real name) of Sherman Oaks, who opted for school instead of $64 for an illegal U-turn. ``It was actually quite interesting and valuable, and entertaining.''

Mr. Flaherty had wanted to argue his case in trial with the arresting officer. But when it came down to it, he wasn't sure whether his backing into a side driveway before heading the opposite direction was legal. Instead of pleading ``innocent'' and risking a guilty verdict, he asked for traffic school.

The bailiff handed him a brochure with dozens of available schools - each costing about $17 to $40 - and gave him about two months to bring back his graduation certificate. Failure to do so results in warrant, arrest, payment of original ticket, and expensive penalty - about $180. Courts still collect a $22 administrative fee, as well.

Schools take place at a myriad of venues, conference rooms at local hotels or VFW posts. Using chalkboards and overhead projectors, teachers talk about the violations of those in the class, how they could've been avoided. They also help clear up the sometimes confusing plethora of new laws or practices that have been instituted by the state - rules that licensed drivers may be unaware of.

One recent change in California is a new way to paint lines for left-hand turns. ``How does one find out about these changes if he hasn't read his driver handbook recently?'' asks Mr. Elkins. ``Traffic school,'' comes the chorused response.

Such schools have been around since the '50s in California. As of last fall, 43 states had them. But after complaints about loose accreditation grew louder through the '70s, the Legislature here enacted a law in January 1985 requiring licensing of schools. Now strict guidelines affect teachers, curriculum, course length, and cost.

Defensive driving is encouraged. Teachers use statistics to show how many pedestrians were killed or injured, or cars and motorcycles damaged - and for what reasons. Most motorcycle deaths, for instance, occur by head-on collisions with left-turning cars. ``They are hard to see coming,'' points out William Aurand, a police detective who teaches in his off time. ``A ball-point pen in front of your face is wide enough to conceal an oncoming motorcycle.''

Bruce Elkins asks for a cosmetic mirror and gets one student to sit in a chair and use it as if it is a rear-view mirror. Mr. Elkins then exemplifies the issue of mirror blind-spots - why it is necessary to look over your shoulder when changing lanes. Movies are shown about drunk driving and the importance of wearing your seat belts. Injuries and deaths are 25 times more likely, for instance, when a passenger is thrown from a car compared to when he has been strapped in.

``People say, `What if I'm knocked unconscious and can't get out?' or `What if I'm too hurt to get out of the seat belt,''' says one film instructor. ``Well, if you are unconscious or too hurt to get out of the seat belt, you couldn't get out of the car anyway.''

Instructors talk about the letter of the law and the spirit of the law, about how each officer treats ticket writing differently. ``Just because he stops you doesn't mean he will cite you,'' says Mr. Aurand. ``My advice is to start talking before he starts writing.''

There are lots of situations where the letter of the law is hard to interpret. What about attempting a U-turn when the steering radius of your car is not tight enough to make the turn without backing up? What about commiting oneself to a left-hand turn onto a freeway ramp and being foiled by a line of right-hand turners onto the same ramp - none of whom will acknowledge your existence? These kinds of situations and more are discussed with ramifications as well as legal consequences.

``The overall feeling you get is that alot of these situations are confusing for lots of people, that sometimes it's not simply a matter of ignoring the law,'' says another student. ``It makes you more aware of what everyone is up against, and that things go better when you're paying attention.''