Snow plows, salt dispensers and dozens of road crews were thrown into action on area roads and highways once again last night as officials battle the third snow-storm in a week.

With preparations made well in advance of the afternoon onset of the storm, they appeared otimistic about prospect for this morning.

"We expect to have all major arteries clear by the rush hour," said Robert L. Windsor, suoerintendent of road maintenance for Prince George's County.

Commuters, including some who didn't even try to negotiate local streets during last week's snows should find nearly all major arteries salted or plowed by the time they start their cars this morning, officials say.

All of this sound outrageously familiar to commuters who spent two and a half hours Wednesday covering a distance that normally takes 30 minutes.

Yesterday's snowfall was on top of the eight inches that fell early last week. For those looking for omens, [WORD ILLEGIBLE] inches of snow fell in January, 1961, just before the inauguration of John F. Kennedy, according to weather service officials.

Prince George's County crews were concertrating on Addison, Riverdale, Kulu Branch, Dahlhouse, Rosaryville, and Good Luck roads using three dozen trucks to sand area streets, Windsor said.

Montgomery County residents will find that such major arteries as Randolph Road, Demoncracy Boulevard, Bei Pre Road and Twinbrook Parkway have been handled by the county crews, according to Jim Arnoult, chief of the county's highway maintenance division.

Other Montgomery County roads that got priority during last night's snow, which began around 5 p. m., and should be clear this morning, are Shady Grove Road, Arcola Boulevard, Aspen Hill Road, and Bell's Mill Road, he said.

Maryland state highways in the two counties - such as Old Georgetown Road, Viers Mill Road and Bradley Boulevard - were salted on a "need" basis, according to Frank Thompson, a resident maintenance engineer.

In the District, 84 sanding trucks were rolling by 6 p. m. yesterday to keep such major thoroughfares as Connecticut, Florida, Massachusetts, New York, Pennsylvania, and Rhode Island Avenues clear of snow, which stuck quickly to the frozen streets yesterday.

In Virginia, Interstate Highways 495 (the Capital Beltway), 95, and 66 were salted as soon as the snow started flying. Arlington Boulevard, Lee Highway and Chain Bridge Road were also among the roads treated for the storm.

In fact, Virginia state road crews began salting those streets before the storm, so the snow would not stick at all, according to Donald E. Keith, a highway department engineer.

Officials also speculated on why some drivers here may still have problems driving in the snow.

%We have people here from south of the equator," said Donald E. Keith, resident engineer in Fairfax for the Virginia Highway Department. "For some of them this is the first snow they've ever seen."

For others Keith suggested a lack of "snow tires or snow chains was the cause." Besides, he said, "some people only drive in two speeds: stop and full throttle. You just can't drive that way in the snow," he said.

Seward Cross, deputy assistant director in the D. C. Bureau of Traffic Engineering and Operations, offered this advice for the apparent thousands who find Washington's comparatively light snowfalls cause for panic and alarm.

"Don't drive," he suggested, "unless it's absolutely necessary. If you do drive, use the lowest gear possible." He added, however, that second gear is better to use when going uphill than first gear because it provides better traction.

"Don't brake unless you have to," Cross said. "Once the wheels lock on an icy surface you've lost control of the car's direction. When you do brake, use a short, light, pumping motion," he said.

Finally, he said, " keep both hands on the wheel."

The snow blanketing the metropolitan area for the past week marks a reversion "to a (weather) pattern that was more common in the early 1960s," according to Harold Hess, a forecaster with the National Weather Service. "We've become spoiled in the last four or five winters when temperatures have gone above normal . . . and we haven't gooten much snow," he said.

The old pattern includes heavier snowfalls and plenty of days with freezing temperatures, he said."We can probably expect more snow on Wednesday," Hess said. He added that because of continued low temperatures snow already on the ground can be expected to remain.

The current storm, which has moved up from the lower Mississippi Valley, is headed in a north-eastern pattern, Hess said. "Places in the Ohio Valley and other areas north and east of us will get a lot more snow than we'll get," he added.

The Washington area annually gets about 19 inches of snow, the weather service said.

Road crew officials said drivers were instructed to spread salt on roads "with care," according to Cross of the District's traffic engineering bureau.

%Salt can harm trees, plants and shrubbery," he said. Salt is spread mainly on arterial streets, while a less potent salt-and-sand mix is spread in residential areas.

Virginia authorities reported they had used more than 5,000 tons of salt during last week's snow at $17 a ton. Highway department official Keith reported that Virginia crews were expected to use 500 tons preparing for this morning's traffic.