A LOOK AHEAD * Some long-overdue help is on the way for one of downtown’s most treacherous thoroughfares: A two-year, $4.4-million construction project aimed at . . . : Giving L.A.’s Broadway the Make-Over Treatment

One of downtown Los Angeles’ most important construction projects is finally about to begin.

It is not the new Disney Concert Hall, nor the Roman Catholic Cathedral, nor the Staples sports arena. Work begins next month to rebuild Broadway, a critical urban street so riddled with bumps and craters that a bone-jarring drive along its heavily traveled length resembles a stagecoach ride through the Old West.

If the city had a Top 10 list of pothole complaints, Broadway--one of the city’s busiest Latino shopping districts--would easily make it. The rail from long-abandoned streetcars has even broken the surface at times.

“I’ve only heard the complaints from pedestrians, mostly female business people who have difficulty traversing the street in high heels,” said Francine Lipsman, general manager of Bradbury Associates, which manages the historic Bradbury Building.

Construction is expected to take at least two years. But plans call for keeping one or two lanes open in each direction at all times.

The Metropolitan Transportation Authority is paying for most of the $4.4-million project because--believe it or not--it thinks a smoother, more comfortable bus ride will promote public transit ridership.

City officials who receive the claims for damages caused by chuckholes felt that the MTA should help pick up the bill because of the pounding that Broadway takes from buses--often with full passenger loads--making about 1,700 trips a day in each direction. A transit authority spokesman said Broadway is one of the city’s busiest transit corridors, carrying about 50,000 bus riders a day.

Plans call for tearing up the pavement and laying down a 10-inch-thick layer of concrete on Broadway between Olympic Boulevard and Temple Street. The century-old sewers under Broadway will be reinforced. A decorative, palm-lined sidewalk featuring brighter street lights on historic lampposts also is planned under a separate $2-million project, also largely funded by the MTA.

City engineers first recommended that the street be reconstructed more than a decade ago.

“Nothing got done because of all the competing proposals” for Broadway, said Leslie Henderson, assistant engineer in the bureau of engineering’s street improvement division. “Yet Broadway continued to deteriorate.”

The street was resurfaced in 1986, but that was like applying a Band-Aid to a broken artery because the underlying problem--shifting soil under the roadway--remained.

“When you start having subsoil movement, there is no way that you can correct that unless you dig out the street, stabilize the subsoil, and then build a roadway on top of it,” said Henderson. “If you don’t do that, and continue to try to pave it over with asphalt, it’s sort of like throwing material down a hole with no bottom to it.”

The street has not been reconstructed for decades. “We still have remnants of granite curb out there, when stone masons were setting curb,” said Henderson. “Some of that probably predates the turn of the century.”

In an effort to minimize the disruption to businesses during the Christmas shopping season and Fiesta Broadway, work will take place in phases: between Olympic and 5th from mid-July until mid-November and, if unfinished, resume in January; and between 5th and Temple from May to November of next year. Cross streets may be narrowed to one lane in each direction at times.

In preparation for the project, Hill Street was recently converted from one way to a two-way street between Temple and 12th to handle the traffic diverted from Broadway. Traffic engineers working in the city’s automated control center also plan to change the timing of traffic lights to steer vehicles around detours.

While the orange traffic barricades and flashing arrows are sure to be nuisances, motorists will end up with a street as smooth as a razor shave.

Until, of course, utility crews dig a trench.

“That is our worst nightmare,” said Henderson. “Every time we see a utility company, we just say, ‘Ohhh, here it goes, our brand new street.’ ”

But under a new municipal ordinance, utilities that dig up a street within a year of repaving will be responsible for repaving the street.