The State Highway System and
SR 13 in Berkeley California's highway system is governed pursuant to Division 1 of the California Streets and Highways Code, which is one of the 29
California Codes enacted by the state legislature. Since July 1 of 1964, the majority of
legislative route numbers, those defined in the Streets and Highways Code, match the
sign route numbers. For example,
Interstate 5 is listed as "Route 5" in the code. Some short routes are instead signed as parts of other routes regardless of legislative definition. For instance,
Route 112 and
Route 260 are signed as part of the longer
State Route 61.
Route 51 is signed as
Interstate 80 Business, but is done so under legislative mandate in section 351.1. The Streets and Highways Code allows for non-contiguous segments of state highways, which are logged by Caltrans using the route's
postmile data, picking up where it leaves off at any legislative breaks in the state highway as originally measured. To avoid duplication,
concurrencies are only listed in one of their respective highway's definition, and are treated as non-contiguous segments in their other highways' definition. For example, the
I-80/
I-580 concurrency, known as the
Eastshore Freeway, only falls under the Route 80 description in the highway code while the definition of Route 580 is broken into non-contiguous segments. However, Caltrans may not sign all concurrences. For example, while
Route 1 is generally co-signed along
Route 101 between its disconnected segment from
San Francisco to
Sausalito, Route 1 is not co-signed along Route 101 between near the
Ventura-
Santa Barbara county line and
Las Cruces. The state highway system may be expanded by either construction of new state highways or adoption of local highways as state highways. Section 75 allows the
California Transportation Commission to select, adopt and determine locations for state highway routes, while Section 90 empowers
Caltrans to construct and maintain said state highways between the termini designated by the routes listed in Chapter 2, Article 3. Section 81 allows the commission to adopt local highways as state highways, and without compensation as stated in Section 83, as long as the adopted route meets eligibility requirements. Said requirements include that the road be traversable from end-to-end, must exist along a route defined in Chapter 2, Article 3 to be superseded or yet to be constructed, be contiguous to a portion of the state highway system currently maintained by Caltrans, and be constructed to adequate standards. For example, Seal Beach Boulevard in the
City of Seal Beach between
Route 1 and
Route 405 would be eligible for adoption under Section 81, as its traversable alignment matches an unconstructed portion of
Route 605 as defined in Section 619, subdivision (a). By law, an adoption under this section would sign the route as State Route 605. Section 73 of the code permits the commission to
relinquish any portion of a state highway to a city or county that has been deleted via legislative enactment or superseded by relocation, but only after the highway has been placed in a state of good repair as defined in Section 23. Legislative deletion can involve the superceding of a state highway route by a different state highway route that serves a similar corridor, such as the completion of
Route 105 forcing the deletion of
Route 42, or an agreement between the state and city or county to transfer a portion of state highway to local control based on the desires of either entity. Depending on the relinquishment, the local jurisdiction may be required to install and maintain signs directing drivers to the continuation of that highway. These portions of state highway relinquished are deemed by the legislature to be ineligible for future adoption under Section 81. In most cases, these highways are ineligible by default as the route's definition is amended by the legislature.
Alternate routes California state highways have three types of alternate routes:
Business routes, unrelinquished routes, and supplemental routes. Alternate routes are not defined by the Streets and Highways Code. Business routes are not state highways and are instead locally maintained, unless they overlay other routes of the state highway system (such as
I-80 Bus. in
Sacramento running concurrently with the unsigned
State Route 51 Unrelinquished routes are state highways that have been superseded by a newly constructed alignment via Section 73, but the state and local municipality have yet to come to proper terms and conditions to relinquish the state highway and place it in a good state of repair according to Section 23. These highways carry the suffix
U, such as
Route 8U,
Route 14U and
Route 210U. Unrelinquished state highways can remain on the system indefinitely, with some existing for decades. Supplemental routes are state highways consisting of spurs, truck lanes and bus lanes where all or part of the roadway is a separate alignment. These highways carry the suffix
S. Spurs may constitute highways that were constructed to bypass local traffic, such as
Route 86S and
Route 180S, tolled freeway bypasses, such as
Route 880S, and even unrelinquished routes, such as
Route 5S or
Route 178S. Any parent route that is bypassed by a supplemental route along the same legislative route definition is authorized for relinquishment under Section 73. If relinquished, the supplemental route assumes the parent route. ==History==