Ramps on 10 Freeway to Open This Month : Traffic: New entrances and exits are expected to relieve chronic problems near Lincoln Boulevard.

Six months behind schedule, new entrance and exit ramps to the Santa Monica Freeway (10) in downtown Santa Monica will make their welcome debut later this month, easing some of Lincoln Boulevard’s chronic congestion.

And in another Westside freeway project, Caltrans and Summa Corp. are proceeding with plans to construct a new set of ramps on the San Diego Freeway (405) in Westchester, providing a northbound exit and entrance serving Summa’s Howard Hughes Center development. Work is to begin in January.

The $5.5-million Santa Monica Freeway job has added an eastbound entrance to the freeway at 4th Street. The 18-month construction forced the closure of eastbound Olympic Boulevard between 4th Street and Lincoln Boulevard, as well as the eastbound exit ramp from the freeway to Lincoln Boulevard.

The closure of Olympic has forced additional freeway-bound traffic from downtown Santa Monica over to an already congested Lincoln Boulevard.

The city has tentative plans to celebrate the reopening with a ribbon-cutting ceremony Sept. 24.

Caltrans engineer Scott McKenzie said the six-month delay on the project was the result of about 50 change orders, a rainy winter in ’92 that cost 35 workdays, problems satisfying Santa Monica High School stipulations and the rescheduling of some work to coordinate with the city.

“Some of the delay was so we could better serve the public by combining our work with the city of Santa Monica’s work on 4th Street,” McKenzie said.

The project, financed jointly by the state and federal government, was aimed at providing direct access to the Santa Monica Freeway from the Santa Monica Civic Center, the city’s central business district, a number of new hotels and area beaches. It is also expected to relieve some of the congestion at the Santa Monica Freeway and Lincoln Boulevard interchange, where about 62,000 cars get on or off the freeway in a 24-hour period.

Holly Ackley, an engineer for Santa Monica, said the city was highly supportive of the project because two existing eastbound on-ramps--at Lincoln Boulevard and at Cloverfield Boulevard--are badly congested.

The improvements include:

* Realignment of the Santa Monica Freeway’s eastbound exit to Lincoln Boulevard.

* Construction of a new eastbound entrance ramp to the freeway at 4th Street.

* Realignment of Olympic Boulevard between 4th Street and Lincoln Boulevard into a one-way, eastbound road intended for local use.

* Construction of an auxiliary lane on the eastbound Santa Monica Freeway from Lincoln Boulevard to the 20th Street exit.

* Realignment of the existing eastbound freeway entrance ramp from Lincoln Boulevard to 20th Street, and modification of the ramp to provide for two full lanes of traffic.

* Removal of the 7th Street pedestrian bridge over the freeway.

Ackley said Caltrans will soon begin landscaping along the south side of the freeway from 4th Street to 17th Street.

As the Santa Monica project is wrapping up, the construction job in Westchester is about to begin. It is part of $15 million in traffic mitigation measures that Summa Corp. agreed to in order to gain permission to build the Howard Hughes Center.

Howard Hughes Center, which stands next to the San Diego Freeway at Centinela Avenue and Sepulveda Boulevard, is a 70-acre business park whose first phase of construction has been completed. Summa is a private corporation created by the late industrialist Howard Hughes.

Kathy Zimmerlin, director of planning and design at Summa, said the addition of the northbound on- and off-ramps “will complete a full directional ramp system from Howard Hughes Center so that drivers (to or from the center) will not cut through surrounding neighborhoods.”

Southbound on- and off-ramps were relocated in 1984 from Sepulveda Boulevard to Howard Hughes Parkway. Caltrans and Summa split the costs for that project.

In addition to the new ramps, improvements will include:

* Lengthening the San Diego Freeway’s northbound La Tijera Boulevard on-ramp so there is more queuing-up distance.

* Widening the San Diego Freeway bridge that crosses over Centinela Avenue by one lane.

* Erection of a sound barrier to mitigate freeway noise.

Zimmerlin said no roads will be closed during the construction, except possibly for outside freeway lanes in non-peak hours.

The project is out to bid and is expected to be completed sometime in 1994.