Two of California's most heavily traveled -- and traffic clogged -- highways have moved closer to major improvements.

The Central Valley congressional delegation united Thursday in a successful effort to insert a provision in the federal highway spending bill which would begin the process of designating Highway 99 between Stockton and Bakersfield an Interstate highway.

The move is a first, but major, step to begin the process of upgrading the 254 miles of roadway, said to be the nation's most heavily traveled north-south highway that's not an Interstate.

"By obtaining Interstate status, Highway 99 will have access to increased federal funding, which will help widen and repair Highway 99," says Rep. Jim Costa, D-Fresno, who has been credited with leading the congressional efforts on behalf of the highway.

"This is great news for the Central Valley as Highway 99 is the most heavily traveled highway west of the Mississippi River," Mr. Costa says.

In another move that could delight motorists who ventire onto I-205 in Tracy only to think they've turned into an 11-mile long two-lane parking lot, the San Joaquin County Council of Governments has agreed to loan the state $67 million to get constructgion under by next spring to add a lane in each direction.

About 120,000 cars jam onto I-205 every weekday. Skid marks decorate its concrete surface, attesting to how speeds can change from as swift as 50 miles per hour to zero in seconds.

The state is expected to approve the I-205 plan, and put up the rest of the total construction costs of roughly $92 million.

But that's pocket change compared to the estimated $25 billion it would cost to upgrade Highway 99 to Interstate standards.

Some help could come earlier since the highway has also been designated a "high priority corridor."

The designation makes Highway 99 eligible for a special multibillion-dollar federal allocation for repairs.

Voting on the massive $286.5 billion was the last thing the House did before it went off on its annual summer vacation.

“These projects are vital to building and improving upon transportation infrastructure in the Valley,” says Rep. Dennis Cardoza, D-Merced. “These investments will help create new jobs and make desperately needed upgrades in heavily traveled areas."

The federal bill includes for the Central Valley:

• $330 million for the Centennial Corridor Loop, an eight-lane freeway that will connect the Westside Parkway west of Highway 99, to Highway 178 in the northeast part of Bakersfield. This is one of the largest single projects and is in the home town of House Ways and Means Chairman Bill Thomas, R-Bakersfield.

• $100 million for the design and construction of Highway 178 in Bakersfield

• $60 million for widering of Rosedale Highway between Highways 43 and 99 in Bakersfield and the widening of Highway 178 between Highway 99 and D Street in Bakersfield

• $14.4 million to widen state Route 132 from Highway 99 west to Dakota Avenue. The heavily-traveled road "has been laden with fatal accidents in recent years," according to Mr. Cardoza.

• $2 million for improving county road J59 in Tuolumne, Stanislaus and Merced counties.

• $2.8 million for improving 16 roads, a bridge and a bike path in Mariposa County.

• $1.6 million for studying an Altamont Pass alternative.

• $2.8 million for improving two-lane rural roads in Fresno County.

• $6.5 million to widen Highway 99 between Goshen and Kingsburg in Tulare County

• $7.6 million to improve Freeway 180 in Fresno County

• $1.2 million for a new stoplight along Avenue 416 in Dinuba.

• $240,000 for traffic flow improvements to the intersection of Willow and Herndon in Clovis

• $2.8 million for rehabilitation, repair and reconstruction of "deficient two-lane roads" that connect to I-5 and Highways 99, 41 and 180 in Fresno County

• $400,000 for a project study report for a new Highway 99 interchange with Highway 165 and Bradbury Road in the Turlock area

• $1.2 million to widen Avenue 416 in Dinuba

• $1.2 million to widen Friant Road in Fresno County to four lanes with bicycle lanes

• $1.6 million to improve Highway 219 to four lanes in the Modesto, Riverbank and Oakdale areas

• $2.4 million for improvements to the Highway 99 interchange for central Galt

• $7.6 million for improvements to Freeway 180 in Fresno

• $1.6 million for a study on realignment of Highway 130 in San Joaquin and Santa Clara counties

• $3.2 million for rehabilitation of Tulare County's farm-to-market road system

• $3.2 million to build a full-access interchange at Highway 120 and McKinley Avenue in Manteca

• $400,000 for construction of the University of California, Merced Campus Parkway in Merced County

• $800,000 for a study of an interchange on I-205 at Chrisman Road in Tracy

• $2.4 million to improve the Highway 99-Highway 145 interchange in Madera

• $4 million for a study of building Highway 239 from Highway 4 to I-205 in Tracy

• $3.2 million for improvements to Highway 99 at Sheldon Road

• $800,000 toward construction of an interchange at I-205 and Lammers Road in Tracy

• $4 million to complete thje engineering design and buy right-of-way for the Arch-Sperry road project in Stockton which is to improve the connection between Highway 99 and Interstate 5.

• $2.4 million for the widening of Highway 198 between Highways 99 and 43 in Kings County

• $1.6 million for improvements to the Ben Maddox Way bridge in Stockton

• $7.2 million for a study and construction of Daggett Road to serve the Port of Stockton

• $92 million for planning and construction to widen Highway 41 in Kern County to I-5 in San Luis Obispo County

• $3 million to convert an abandoned Union Pacific railroad route into a bicycle trail in Modesto

• $500,000 for environmental reviews for possible improvements to various I-5 interstanges in the Stockton area

• $1 million for improvements to Highway 4 between Stockton and Angels Camp

The federal funds cover only a portion of the costs in most cases; state and local money is usually required to pay the full cost.