When the
Department of Engineering laid out the initial state highway system after the state's voters approved a
bond issue to pay for it in 1910, they included
Route 5, connecting
Santa Cruz and
Oakland with
Stockton via
Altamont Pass.
San Joaquin County paved the portion near
Tracy with
asphalt with their own bond issue, passed in 1909, and the state later resurfaced it with
concrete. In addition, the new concrete road bypassed
Banta, which the old county road had passed through via Banta Road, F Street, and Grant Line Road. Otherwise, the road was relatively direct, coming down from Altamont Pass onto Grant Line Road, following
Byron Highway into Tracy and leaving east and northeasterly on 11th Street to the
San Joaquin River at the
Mossdale Crossing. The
Lincoln Highway Association chose this route in 1913 for their transcontinental highway, where it remained until the
Carquinez Bridge opened in 1927, creating a shorter route via
Vallejo. In 1926, the
American Association of State Highway Officials designated the Stockton–Bay Area route as
US 48, which was absorbed by an extension of
US 50 by the early 1930s. A 1938 four-lane bypass of the old road around Altamont Pass was extended east to Tracy as a four-lane
expressway on November 16, 1954. By then, the entire route between the Bay Area and Stockton was four or more lanes, following the present
I-580 (eastbound lanes where they separate During early planning for the
Interstate Highway System, the main north–south route through California (now I-5) was to use
SR 99 through the San Joaquin Valley; a connection to the Bay Area split near
Modesto and roughly followed US 50. The
Bureau of Public Roads approved a move to the proposed
Westside Freeway in May 1957, and, in November, they added a
North Tracy Bypass that would connect I-5 and I-580. Construction began in the late 1960s, incorporating part of the 1954 expressway and a new alignment bypassing Tracy to the north, and the $14-million (equivalent to $ in ) road opened to traffic on December 21, 1970. (A short piece at the west end, including the bridge over the
California Aqueduct, was upgraded several years earlier when I-580 and I-5 to the south were built.) Since 1970, I-205 has seen few changes. The largest have been widening from four to six lanes west of I-205 Bus. in 1999 and converting two
diamond interchanges to
partial cloverleafs—Grant Line Road in about 1997 As of mid-2009, I-205 has been widened to six lanes (three in each direction) for its entire route. Also, the 1970s concrete pavement has been resurfaced with fresh asphalt from the junction of I-5 to due east of the 11th street connector ramp. ==Future==