The majors of Rockville and Gaithersburg want it, numerous civic associations say they want it and even the conservative Chamber of Commerce wants it.

"It" is the proposed increase in the state gasoline tax that would add about four cents a gallon to the present pump price of gas. The Maryland General Assembly didn't pass a gas tax hike last year but may consider the measure in a more favorable light when legislators reconvene this week in Annapolis.

The gas tax, plus a levy on heavy trucks and some increases in motor vehicle fees, would raise the money to begin construction of delayed road and bridge projects in Montgomery County and around the state.

The Montgomery highway projects most desperately needed, but stalled by dwindling receipts for the state's Highway Trust Fund, are those in the traffic-clogged I-270 corridor, about a dozen members of the county legislative delegation and state Highway Administrator M. S. Caltrider were told last week. The officials made their annual appearance in Rockville to receive citizen comment on the proposed five-year state road construction program.

"Traffic jams will have a greater impact than the disastrous building moratorium" imposed in the 1970s if vital road projects are not funded, said John Carman of the Suburban Maryland Home Builders Association.

Among projects called necessary by a dozen speakers were the planned enlargement of interchanges to I-270, particularly at Montgomery Village Avenue, where commuter traffic daily backs up for a mile or more and where, Caltrider admitted, "I don't know of any interchange on any interstate in Maryland where the backup is as great."

Receiving almost equally strong citizen endorsement was the construction of I-370 between I-270 and the new Shady Grove Metro subway station near Gaithersburg, and the reconstruction and widening of half a dozen bridges such as the two-lane railroad bridge on Rte. 355. The highway recently was widened to six lanes and Gaithersburg Mayor Bruce Goldensohn called the railroad bridge a major bottleneck.

Some projects received mixed support, including the proposed Falls Road interchange on I-270, which would help relieve the traffic jams into Rockville from the two exits at Rte. 28 and Montrose Road. Rockville Mayor William E. Hanna Jr. called the new interchange "critical" for traffic to city and county office complexes. But Del. Robin Ficker (R-Montgomery) called the proposal "a slap in the face to every person in Potomac," claiming it would bring heavy traffic into Potomac along Falls Road.

Caltrider said the Falls Road interchange would relieve some of the heavy traffic around Rockville and the project "is on the fast track. We're doing everything we can to speed it up."

Among the road improvement projects that would be speeded up a year or more if the legislature provides increased money for the Highway Trust Fund are Rte. 198 (Sandy Spring Road) near I-95, Rte. 28 (Norbeck Road) west of Georgia Avenue, Rte. 182 (Layhill Road) north of Glenmont and Interstate projects on I-270, I-370 and the most congested section of the Capital Beltway, between I-270 and Georgia Avenue.