State Route 18

Click here for a key to the symbols used. An explanation of acronyms may be found at the bottom of the page.

Routing

1. From Route 10 near San Bernardino to Route 210.

   Unconstructed (5 miles). The freeway route adoption was rescinded in 1975. At that time the need for Route 18 southerly of then Route 30 (now Route 210) was a low priority. The portion N of Route 10 (Harrison Canyon Alignment) is needed to meet traffic demands (Waterman Ave.). No local roads adequately fit the description of a traversable highway.

   The 2013 Traversable Highway report notes that, for this segment, freeway route adoption was rescinded in 1975, after a route adoption review in 1974. Because Route 215, Route 259 and Route 210, exist in the area and are parallel north - south freeways, the need for Route 18 southerly of Route 210 to be a state highway is a low priority. No local roads adequately fit the description of a traversable highway.

   Post 1964 Signage History

   ▸In 1963, this route was a single segment, and was defined as "from Route 10 near San Bernardino to Route 138 via San Bernardino, near Mountain View Avenue and via Waterman Canyon, Big Bear Lake, Baldwin Lake, and near Victorville."

   Scott Parker on AARoads provided some insight on the 1963 definition:
   (Source: Scott Parker on AARoads, "Re: CA 259", 5/24/2019)

   Before the 1958-59 construction of the (then) I-15 (now I-215) freeway north from I-10 into central San Bernardino, Sign Route 18 (aka LRN 43) took a convoluted path through downtown: coming into town multiplexed with US 91 and US 395 on Mt. Vernon St., then turning right on 3^rd Street (at the south end of the old Mt. Vernon bridge over the Santa Fe yards) to E Street, then turning north on E to Highland (LRN 190/Sign Route 30). It then turned right on Highland a few blocks to Sierra Way, turning north until that street segued into the original two-lane Sign Route 18 up into the mountains. Two things happened with the '64 renumbering: new Route 18 came out of the mountains (SB) and at least was intended to temporarily terminate at Route 30; a typical Division of Highways/Caltrans unadopted "dotted line on a map" showed Route 18 extending south more or less along Waterman Ave., the major N-S arterial in the area, all the way to I-10 in the Loma Linda area between Colton and Redlands. When Route 18 was improved in the mountains (opened in early '71) to a 4-lane expressway, its "flatland" alignment was in fact shifted a few blocks east to Waterman Ave. rather than the previous Sierra Way alignment, because the latter could not easily be expanded to 4 lanes, while Waterman could. Curiously, Sierra Way was signed as "BR 18"— although it traversed a decidedly residential neighborhood. Route 18 was signed down to the then-Route 30 freeway; initially signage took it west on Route 30 to the present Route 259 "cutoff", then right over that freeway to a terminus at (then) I-15 (which became I-15E at the end of 1972 and I-215 ten years later). Somewhere in the mid-70's any Route 18 signage—reassurance or trailblazer—was removed south/west of the Waterman Ave. interchange with Route 30; signage from I-15E/I-215 NB onto Route 259 was "TO Route 30 EAST" with a secondary line "TO Route 18/MOUNTAIN RESORTS"; from Route 30 WB it was "TO I-15E (I-215) SOUTH". Variations on that signage persisted even when Route 30 was extended west to I-215 and east to Redlands (and Route 330) by 1992; [even by 2012] the configuration was the same (but now referring to Route 210 rather than Route 30, of course). The gist of the matter was that originally Route 18 was intended to extend south across the east end of San Bernardino; as that never occurred, Route 259 remains part of the most direct connection between much of the regional freeway network (Route 210 to the west notwithstanding) and the main artery up the mountain to the Crestline/Lake Arrowhead area—essentially functioning, as it has since its opening in the late '60's, as a natural extension of Route 18.

   ▸In 1965, the definition was relaxed to "Route 10 near San Bernardino to Route 138 via San Bernardino, Waterman Canyon, Big Bear Lake, Baldwin Lake, and near Victorville."

   In 1974, hearings were held by Caltrans on the question of whether planning for the unconstructed portion of Route 18 (called the "Harrison Street Freeway") should be continued. There were two segments that had been adopted previously: a segment N of Route 210 (Route 30) and the segment between I-10 and Route 210. At the time, there were no plans nor funds to construct the freeway, and so planning for construction just hindered development.
   (Redlands Daily Facts, 11/28/1974 via Joel Windmiller, 1/29/2023; Image Source: San Bernardino County Sun, 11/27/1974, via Joel Windmiller 2/25/2023)

   ▸In 1984, Chapter 409 split the definition into two parts: (a) Route 10 near San Bernardino to Route 15 via San Bernardino, Big Bear Lake, and Victorville. (b) Route 15 to Route 138.

   ▸In 1986, Chapter 928 tightened the language for this segment to be "Route 15 in Victorville via Big Bear Lake".

   ▸In 1994, Chapter 1220 split the segment again into "(a) Route 10 near San Bernardino to Route 30. (b) Route 10 [sic] near San Bernardino to Route 15 in Victorville via Big Bear Lake." AB 1650, Ch 724, 10/10/99, corrected the reference to Route 30, which had been renumbered as Route 210.

   Pre 1964 Signage History

   In 1934, Route 18 was signed along the route from Jct. Route 19 near Artesia to Victorville, via San Bernardino and Big Bear Lake. There are some interesting convoluted histories of the pre-1964 segments of Sign Route 18, which we'll discuss in two parts:

   
   

   Pre-1964 Route 18 South and West of I-10

   In 1934, Sign  Route 18 was signed along the route from Jct. Route 19 (Lakewood Blvd) near Artesia to Victorville, via San Bernardino and Big Bear Lake. In 1963, it was truncated to start at I-10. This routing ran along LRN 178 between Sign Route 19 and LRN 43 in Santa Ana Canyon, and then along LRN 43 to San Bernardino.

   See also the pages on US 91 and Route 214 for more history of this segment.

   From Lakewood Blvd, Sign Route 18 ran along Lincoln Ave, Center Street (now Lincoln), Olive (now Lincoln), Anaheim-Olive (which later became Lincoln Blvd near Olive), Sign Route 55, and Santa Ana Canyon/US 91 to Riverside. Today, the portions of former Sign Route 18 W of Route 55 is no longer in the state highway system; it has been supplanted by Route 91 along what used to be Sign Route 14. N of Route 55, Sign Route 18 became Route 91 to Riverside. N of Riverside to San Bernardino, the route has been supplanted by today's I-215.

   LRN 178 was defined in 1933 as "Cerritos Avenue to [LRN 43] near Olive via Anaheim" Cerritos Avenue was later renamed Lakewood Avenue; LRN 43 was to become Sign Route 18 (briefly) and then US 91. The route followed Carson Street, Lincoln Avenue and Center Street (now Lincoln Avenue in Anaheim) between Lakewood Ave (Sign Route 19/LRN 168) and LRN 43. In 1934, this became part of Sign Route 18. In 1947, AASHO approved the extension of US 91 from Barstow to Long Beach.  The extension of US 91 to Long Beach was created from a multiplex of LRN 43/Sign Route 18 (which became US 91), LRN 178/Sign Route 18 along Lincoln Avenue, Sign Route 19/LRN 168 to Los Alamitos Traffic Circle, and west on US 101A/LRN 60 on Pacific Coast Highway.  In 1953, LRN 178 was truncated to the new mainline of US 101 at Manchester Avenue/LRN 174.  This removed the segment of LRN 178 between US 101/LRN 174 east through Anaheim to US 91/LRN 43.  At this tims, US 91 and Sign Route 18 were still routed along Center Street in Anaheim and Olive.  By 1956, US 91/Sign Route 18 were rerouted from the eastern terminus of LRN 178 onto US 101/LRN 174 and then along Sign Route 14/LRN 175 (although a 1958 Thomas Guide still shows Sign Route 18 and US 91 routed along Anaheim-Olive and Santiago between US 101 and Sign Route 55) towards US 91/LRN 43 in Santa Ana Canyon.  In 1957, the legislature clarified the end points of LRN 178 as "LRN 168 (Sign Route 19) near Lakewood and LRN 174 (US 101) near Anaheim." In 1961, Sign Route 18 was truncated to San Bernardino, leaving US 91 as the only Sign Route on LRN 178. In 1963, US 91 was truncated to Barstow; in 1964, former US 91 in Santa Ana Canyon and along Sign Route 14 became Route 91, and LRN 178 became Route 214. Route 214 was to be deleted once the Route 91 freeway was completed.
   (Source: Gribblenation Blog (Tom Fearer), "Former California State Route 214 (former California State Route 18 and US Route 91)", 6/14/2023)

   During 1933, LRN 178 and LRN 174 were defined as highways passing through Anaheim.  LRN 178 was defined as from "Cerritos Avenue to LRN 43 near Olive via Anaheim."  LRN 174 was defined as "LRN 60 via Manchester Avenue to LRN 2/US Route 101 near Miraflores."  LRN 178 (Sign Route 18) would pass through the city of Anaheim via Center Street (partially now Lincoln Avenue), whereas LRN 174 (Sign Route 10) was part of the then unfinished Manchester Boulevard Extension.  By 1942, Sign Route 10 had been truncated to an eastern terminus at US 101 Bypass/Sign Route 19 at Rosemead Boulevard in Downey. On July 1, 1947, the AASHO Executive Secretary notified the California State Highway Engineer that California's request to extend US 91 from Barstow to Long Beach had been approved; this extension brought it through Anaheim along Center Street via a multiplex of Sign Route 18/LRN 178. In 1953, the eastern terminus of LRN 178 was truncated to the new mainline routing of US 101 along Manchester Boulevard in Anaheim.  Despite LRN 178 being relinquished between US 101/LRN 174 and LRN 43, it was still signed as US 91/Sign Route 18 through Anaheim via Center Street.  By 1956, US 91 and Sign Route 18 were realigned onto Sign Route 14/LRN 175 north of downtown Anaheim.  The interim routing of US 91/Sign Route 18 from Lincoln Avenue followed US 101/Manchester Boulevard, Orangethorpe Avenue, Cypress Avenue (now State College Boulevard) and a completed segment of the Riverside (Orangethorpe) Freeway (east of LRN 180). In 1956, the Riverside Freeway (Houston Expressway) (Sign Route 14/US 91/Sign Route 18/LRN 175) opened east of LRN 180/Cypress Avenue to Santa Ana Canyon. By 1957, Sign Route 18 and US 91 were realigned onto the Stanton Avenue Extension along Sign Route 39/LRN 171 in Buena Park.  Both highways briefly multiplexed US 101 towards Sign Route 14/LRN 175 on Orangethorpe Boulevard. In 1962, Sign Route 18 was truncated from Long Beach to San Bernardino. This truncation removed it from US 91/Sign Route 14/LRN 175 on the Riverside Freeway north of downtown Anaheim.
   (Source: Gribblenation Blog (Tom Fearer), "Former US Route 101, US Route 91, California State Route 10 and California State Route 18 in Anaheim", 9/26/2023)

   In 1953, the underlying LRN along Lincoln between Route 55 and US 101 was deleted. It appears that Route 18 signage in the wild along Lincoln may have been retained along city streets, but the state highway maps show Route 18 ending at the jct. with LRN 175 (Imperial Highway, later the Riverside Freeway), and then picking up along Lincoln W of Manchester. The focus of the Department of Highways at the time was signing US 91. After 1953, US 91 was routing along LRN 175 westward to varying degrees depending on the completion of the freeway, heading back down S to pick up the original LRN 178 (Route 18) routing at an appropriate N/S lateral (State College, LRN 180; Brookhurst St; Manchester, Byp US 101).

   W of US 101, Route 18 was supposedly signed with US 91 to Lakewood Blvd. This routing was LRN 178. The route was defined in 1933. In the 1963 renumbering, this became Route 214.

   Sign Route 18 in Riverside

   Within Riverside, Sign Route 18 entered along Magnolia Avenue, originally transitioning over to Main Street at First (note that Magnolia turns into Market at 14^th). It then turned onto Russell, and then onto La Cadena up and into San Bernardino. US 395 joined the mix at Eighth (where LRN 43 met LRN 77). After 1941, US 91 was added. Looking at the modern map, the La Cadena Drive shown E of the freeway is an artifact of freeway construction; the original La Cadena was buried under the US 91/US 395/I-215 freeway. The La Cadena W of the freeway is closer to the original, running up the railroad tracks towards San Bernardino, paralleling the freeway that replaced it out of Riverside. 

   Note that one 1942 USGS maps show Sign Route 18 making the transition to Main at 14^th (where Magnolia turns into Market), along a transition curve. This would explain the shape of Newman Park. This same map shows a more convoluted route to La Cadena, transitioning at 1^st to Orange, and then turning from Orange onto Russell. Note that the curve from Magnolia onto Market exists on other 1942 maps; it just isn't part of Sign Route 18.

   On AARoads, Scott Parker noted:
   (Source: Scott Parker on AARoads, “Re: Early US 91 south terminus”, 11/6/2020)

   Although there were several iterations of US 91 alignments over the years, in SoCal it could be signed continuously on appropriate existing streets from the corner of PCH and Atlantic in Long Beach all the way out to Tustin Ave. and "Old" Santa Ana Canyon Road in east Anaheim, Santa Ana Canyon Road in Anaheim Hills (as far east as Yorba Linda Blvd.), and the continuous run of 6^th Street in Corona, Magnolia Ave., Market St., and North Main Street in Riverside -- but taking it over Russell Street (now simply a city street dead-ending at the present Route 91 freeway) would today be historically accurate but pointless.  From there up to Highgrove the old US 91 alignment is buried under the Route 91 and I-215 freeways; it diverges onto surface streets again at the La Cadena exit, with the alignment up to Mount Vernon in San Bernardino being intact through Colton—with two 90-degree turns onto old US 70/US 99—so that would tie in with the Cajon Blvd. alignment that is discussed in the Historic US 66 thread.  Of course, US 91 historical signage could be "multiplexed" with that of US 66 all the way from Victorville to Barstow before breaking away in the center of that town.  But beyond that, I-15 mostly lies atop historic US 91 except for a few miles near Calico and the business loop through Baker.

   Sign Route 18 in San Bernardino

   Within San Bernardino, Sign Route 18 generally ran along part of LRN 26, defined in 1916, as part of a spur off of LRN 26 from Colton to connect to San Bernardino (presumably, as a county seat) ["together with a connection from near Colton to San Bernardino"]. In 1959, this segment was redefined to be LRN 275, and the spur that was part of LRN 26 was deleted. N of the LRN 26 Spur, LRN 43 picked back up and was Sign Route 18, at least as far as LRN 190 (Sign Route 30, which eventually became Route 210).

   Sign Route 18 left Riverside along La Cadena Drive via LRN 43. It jogged over to La Cadena just N of Riverside, and followed La Cadena to Valley Blvd (LRN 26, US 70/US 99). Sign Route 18 followed Valley to Mt Vernon, where it turned and went N on Mt. Vernon (LRN 31, Sign Route 18/US 91/US 395). It curved on 3^rd over to E Street, and then up E Street to Highland. Based on maps, it might have continued along Valley to E Street directly, as E Street was LRN 26 and LRN 43. That's particularly possible after the LRN 31 segment on Mt. Vernon S of 5^th was dropped. It jogged on Highland over to Sierra Way, where it then continued N.

   Additional San Bernardino Notes

   The original LRNs in San Bernardino were equally convoluted according to Scott Parker (Sparker). The "spine" LRN through the region was LRN 43, which followed Sign Route 18 throughout the region; a number of long-distance LRNs terminated at this legislative route. LRN 26 was US 99 south of the 3^rd Street/E Street intersection, following US 99 all the way to the Mexican border at Calexico. LRN 31, which carried US 66 over Cajon Pass to Barstow, and US 91 (which was not extended south of Barstow until 1947) northeast from there to Nevada, began at the junction of Mt. Vernon and 3^rd Street and was the Mt. Vernon RR bridge and US 66 east from there. LRN 9 was US 66, and originally US 99, extending west from LRN 31 on 4^th Street toward Pasadena. Sign Route 30/Highland Ave. was LRN 190, and North E Street and Kendall Ave. Business US 66 was LRN 191.

   Scott Parker (Sparker) noted in that discussion that this arrangement didn't last long; the bridge over the Santa Ana River connecting Colton Ave. in the south reaches of San Bernardino with Valley Blvd. in central Colton was completed circa 1931; LRN 26 and US 99 were rerouted west along that alignment. South E Street from the rerouted US 99/LRN 26 became a realigned but unsigned LRN 43. 3^rd Street, still carrying Sign Route 18, became an eastern extension of LRN 9, which terminated at 3^rd and E Street at LRN 43 (Sign Route 18 still turned north there). The entirety of Mt. Vernon north of Valley Blvd. in Colton was reassigned to LRN 31; it still carried Sign Route 18 south of 3^rd Street until US 395 was commissioned in 1934 to join it. US 99/LRN 26 continued west from Colton on Valley Blvd. into Ontario, where it was renamed Holt Ave.

   Similar to 4^th street west of Mt. Vernon, 3^rd Street past the original Santa Fe depot (now used by Metrolink & Amtrak) east of the Mt. Vernon bridge features portions of the original segmented concrete pavement that once carried US 99 & Sign Route 18. The east-west Valley Blvd. alignment that eventually became US 99/LRN 26 was in place as a county facility at the time US 99 was routed through central San Bernardino, with its east end at or near Mt. Vernon Ave. in Colton. The delay involved with realigning US 99 was due to the difficulty experienced in constructing bridges over the Santa Ana River; the riverbed consists of deep layers of sand and silt lying in scooped-out sandstone with no supporting bedrock to speak of. Bridge construction over such a "waterway" required placing concrete caissons deep into the sand and waiting for them to settle before constructing bridge piers upwards from them—then letting the whole assembly settle even more before extending a bridge deck over the piers. This method has continued to this day; the I-10, I-215, and Route 210 bridges over the Santa Ana River were deployed in a similar manner. The original US 99 E Street bridge was the only exception; it was a relatively light "trestle" structure sitting atop the silt layers; it was replaced by the present caisson-based structure in the mid-'60's, a few years after the original I-10 and I-15 (now I-215) bridges were built.
   (Source: Scott Parker (Sparker) @ AAroads, 7/7/2016)

   In August 2025, it was reported that the landmark Mt. Vernon Avenue Bridge in San Bernardino, which was originally on LRN 31/Sign Route 18, was finally reconnecting the city's westside after completing a nearly five-year project that saw the old bridge, built in 1934, completely disassembled. The disassembly occurred in 2021 after officials rated the bridge "severely deficient" after it received a structural deficiency score of 2 out of 100. The bridge was rebult with four lanes total, two lanes in each direction, as well as a fully developed bike lane for bicyclists, and a fully developed standard sidewalk for ADA compliance. The historic bridge featured an open-air rail column that spanned its entire length, but the new one uses a taller metal rail with a closed column design. However, the design included a solid stamping of that bridge rail to mimic the original look. A bulk of the $244.8 million price tag to upgrade the bridge came from federal funding with nearly $40 million from the city. The bridge sits above one of the largest rail yards in the region and spans 22 railroad tracks.
   (Source: LAist, 8/23/2025)

   In 1959, LRN 275 was created as a new route along Highland, running between LRN 26 and LRN 190, eliminating the need for the LRN 26 spur.

   Note: See the history of US 99 in San Bernardino for more information on the historical routing of Route 18.

   Things became particularly messy with the construction of the LRN 43/LRN 31 freeway, which eventually became I-215. LRN 43 seemed to disappear at LRN 26, with the actual traffic routed along the LRN 26 extension N of Colton to pick up LRN 43 again N of LRN 9 (5th Street). US 91 / US 395 appears to have been routed up LRN 31 until that started to go away around 1957. Sign Route 18 went along LRN 26 and the LRN 26 extension to LRN 43. With the completion of the LRN 43/LRN 31 freeway around 1960, things changed again. US 395 and US 91 were routed along the LRN 43 freeway (and US 66 was added to the mix N of LRN 9), with Sign Route 18 moving to the new LRN 275. Just S of LRN 190 (Sign Route 30, now Route 210), LRN 43 split to the N, and LRN 31 continued to the NW. LRN 31 carried US 395 / US 91 / US 66. Signage on the LRN 43 segment is unclear; it eventually became Route 259. Today, this is all I-215 and Route 259.

   ---

2. From Route 210 near San Bernardino to Route 15 in Victorville via Big Bear Lake.

   Post 1964 Signage History

   ▸This segment was created in 1994 (Chapter 1220) from a split of former segment (a), which was created in 1984, with the wording tightened in 1986. Former segment (a) in 1986 read: "(a) Route 10 near San Bernardino to Route 15 in Victorville via Big Bear Lake.". It was split into "(a) Route 10 near San Bernardino to Route 30. (b) Route 10 [sic] near San Bernardino to Route 15 in Victorville via Big Bear Lake." In 1996, Chapter 1154 changed "Route 10" to "Route 30".

   Additionally, the original routing was relocated to Lakeview Drive in Big Bear Lake per the route adoption dated 5/23/91.

   Note that a big numbering switch also occured in 1964. Prior to 1964, Route 18 ran N from San Bernardino. At Running Springs, it joined with Route 30 (now Route 330) up from Highland, and continued cosigned Route 18/Route 30 to the W end of Big Bear Lake. At this point, Route 30 ran along the S edge of the lake, and Route 18 ran along the N end. When the new definitions went into place, Route 18 was rerouted to the S side of Big Bear Lake (replacing what had been signed as Route 30). The cosigning that existed between the W end of Big Bear Lake and the Route 30 (now Route 330)/Route 18 junction was eliminated, and the route was just signed as Route 18. The old Route 18 routing on the N side of the lake was signed as Route 38.

   Pre 1964 Signage History

   In 1934, Route 18 was signed along the route from Jct. Route 19 near Artesia to Victorville, via San Bernardino and Big Bear Lake. Before 1964, this segment was LRN 43. The segment between Route 30 and Big Bear Lake dates to 1917 (when it was Crest Drive; later Rim of the World Highway) the remainder was an extension defined in 1933 (note that LRN 43 was defined to include a route around Big Bear Lake, and thus covered both the northern and southern routes along the Big Bear Lake). Maps, however, are ambiguous and the southern side of the lake could also have been LRN 190 (which was defined to end at LRN 43 at Big Bear Lake, but it didn't specify which end). The northern side of the lake was Sign Route 18. The southern side was Sign Route 30, although some maps show it as Sign Route 18 as well. What is clear is that after 1964, the N side was Route 38, and the S side was Route 18. The crossover, in Big Bear City, was LRN 43 and clearly Sign Route 18.

   Crest Drive/Rim of the World Highway was initially constructed in 1852 as a logging road by Mormon settlers in what is now modern day San Bernardino County. Crest Drive became suddenly increasingly important following the discovery of Gold in Holcomb Valley located near modern day Bear Lake. A large town known as Belleville developed around the Holcomb Valley mining claims. Growth in Belleville was so rapid that it almost took the San Bernardino County seat from San Bernardino. Although the Gold Rush in Holcomb Valley last about a decade mining continued in the area until the 1910s. By the turn of the 20th Century the crest of the San Bernardino Mountains had become an increasingly popular locale for recreation. It appears that one of the primary drivers in adding Crest Drive to the State Highway system was likely to eliminate the toll facility in the area. A 1919 Third State Highway Bond Act measure extended LRN 43 over Bear Valley Dam, this is reflected on the 1920 State Highway Map. Previously LRN 43 had been routed north of Bear Lake (which would become part of Route 38).
   (Source: Gribblenation Blog - California State Route 18; the Rim of the World Highway to California State Route 138)

   Victorville provides another example of a rerouting in the late 1940s to eliminate a number of dangerous curves. Note from these comparison maps how the old Route 18 is still visible as a dirt trail near the current highway. The previous Route 18 routing had seventeen curves, some of them "hairpin" variety with radii as short as 50 feet that made it impossible for trucks and trailers to negotiate them without blocking traffic or risking collision. The revised routing has four curves of easy transition ranging in radii from 1,000 to 2,000 feet designed for a safe driving speed of 50mph.

   Tom Fearer provided a chronology of the mountain routings:
   (Source: Tom Fearer (Max R) on AARoad, "Re: CA 18", 10/1/2019)

   • The precursor to Route 18 from San Bernardino up Waterman Canyon to Big Bear was known as Crest Road which was constructed as a logging route in 1852 by Mormon Pioneers. Crest Road was gradually improved as mining interest in Holcomb Valley and with water rights in Bear Valley increased over the following decades.
   • In 1917 LRN 43 was adopted from where the pavement in Waterman Canyon ended east towards Bear Valley north of Bear Valley Lake.
   • In 1919 a spur of LRN 43 was extended over Bear Valley Dam east through modern Big Bear Lake and Big Bear City.
   • In 1931 LRN 43 was extended northwest from Bear Valley to US 66 in Victorville, south out of Waterman Canyon to San Bernardino and southwest to Newport Beach.
   • In 1934 LRN 43 was signed as Route 18 between US 66 in Victorville and Route 55 near Olive. Route 18 then ran to Lakewood along Harbor Blvd using LRN 178.
   • In 1947 US 91 was extended from Barstow to Long Beach. This extension included a multiplex of Route 18 from San Bernardino to Lakewood, and then down Route 19 to Long Beach.
   • Route 30 appears to have first been signed in 1954 and had an eastern terminus at Route 18 in Running Springs.
   • In 1957 Route 30 was extended east on a multiplex to Bear Valley. Route 30 ran along the south shore of Bear Valley whereas Route 18 stayed on it's original alignment on the north shore.
   • In 1962 Route 18 was truncated to end in San Bernardino where it ended at US 66/91/395.
   • In 1964 Route 18 west legislatively extended west from Victorville to Llano on what was the unbuilt LRN 268. Route 18 was also shifted to the south shore of Big Bear Lake and Route 38 took over the previous north shore alignment.
   • In 1965 Route 18 was truncated to CA 30 in San Bernardino whereas the previous stub to US 66/91/395 became Route 259.
   • The western extension of Route 18 from Victorville to Llano was complete by 1967.
   • By 1970 Route 18 between San Bernardino and Route 18 was completed to expressway standards.
   • In 1991 Route 18 was shifted out of Bear Valley Lake Village which created the somewhat unofficial Route 18 Business Loop.

   Status

   In September 2012, it was reported that the Caltrans has ordered the CHP to make the 26-mile stretch of Route 18 between Route 138 and Route 38 (~ SBD R17.216 to SBD 44.411) a Daylight Headlight Section. Fines for violations could be as high as $350. The Daylight Headlight Section came about because of a request from community members made during the second annual Community Preparedness Meeting and Open House in 2011 in Lake Arrowhead.

   In April 2006, the CTC heard the results of a draft EIR related to replacement of an existing bridge near Big Bear in San Bernardino County (SBD PM 44.2/44.7). This project is programmed in the 2006 State Highway Operation and Protection Program. The total estimated project cost is $58,314,000. Construction is estimated to begin in Fiscal Year 2007-08. The following alternative are being considered: (•) Alternative 4 - "Lake Crossing", which proposes to construct a new three-lane bridge across the western end of Big Bear Lake that would widen and realign the approach to accommodate the new structure and eliminate a substandard curve on Route 18, as well as signalization of the intersection of Route 18 and Route 38 to improve channelization during peak hour traffic on weekends and holidays, (•) Alternative 5 - "Canyon Crossing", which proposes to construct a new three-lane bridge across Bear Lake Canyon, widening and realigning the approach to accommodate the new structure and realign a substandard curve on Route 18, as well as signalization of the intersection of Route 18 and Route 38 to improve channelization during peak hour traffic on weekends and holidays, or (•) No-Build Alternative. Because Route 18 and Route 38 are part of the United States Forest Service (USFS) scenic byway system and are eligible for listing as State Scenic Highways, any activities that could alter aesthetics are considered significant. The proposed project will remove mature trees and modify large rock outcroppings in the area. It will also modify the gateway view of Big Bear Lake by introducing new and larger transportation elements.

   In August 2015, the CTC approved $3,296,000 for a project in San Bernardino County, on Route 18 (08-SBd-18, 49.1/51.6) in Big Bear Lake, from Pine Knot Avenue to Stanfield cutoff that will construct auxiliary lanes in both directions to reduce congestion and improve highway operations and mobility.

   Cushenberry Creek Bridge (SBD 64.60)

   In May 2009, the CTC approved for future consideration of funding a project that will replace the existing Cushenberry Creek Bridge (SBD 064.60) on a new alignment, remove the existing bridge, improve drainage, and construct roadway improvements near Lucerne Valley. The project is fully funded and is programmed in the 2008 State Highway Operation and Protection Program. Total estimated project cost is $11,639,000, capital and support. Construction is estimated to begin in Fiscal Year 2009-10.

   In August 2011, the CTC approved $100,000 in SHOPP funding for repairs near Lucerne Valley, at Cushenbury Creek Bridge, that will provide landscape mitigation covering one acre area at one bridge replacement project site. Project will maintain existing plants for four years to facilitate plant establishment.

   Realignment - Apple Valley to Adelanto (~SBD 86.886 to SBD 100.873)

   Portions of this routing may be affected by the High Desert Corridor; see Route 138 for a discussion of the HDC. According to SANBAG, the City of Victorville has secured Federal Demonstration funds for the Project Approval and Environmental Document (PA&ED) phase of the High Desert Corridor project. The project realigns Route 18 to a new alignment from Joshua Road in the Town of Apple Valley (~SBD 86.886) to US 395 in the City of Adelanto (~ SBD 100.873). The new facility will be a four-lane expressway. The project is the first phase of the eventual High Desert Corridor linking the Victor Valley to the Antelope Valley.

   Route 18 is a two-lane street with a continuous center turn lane in the Town of Apple Valley and City of Victorville (D Street). When Route 18 junctions with I-15, travelers must follow I-15 south to Palmdale Road, where Route 18 proceeds west. Palmdale Road is a four-lane street until it leaves the city, at which time it becomes a two-lane conventional highway until it terminates at Route 138 in Los Angeles County. The project will realign Route 18 from Joshua Road in the Town of Apple Valley to US 395 in the City of Adelanto. The proposed alignment proceeds north until it nears the Apple Valley Airport, where it turns west. The alignment continues west until it links with Air Expressway near Southern California Logistics Airport in the City of Victorville and proceeds on to US 395. The new facility will be a four-lane expressway with at-grade intersections from Joshua Road to I-15, and will include an interchange at I-15. From I-15 to US 395, the facility will be a four-lane freeway with grade separated interchanges at Phantom East and either Adelanto Road or existing US 395.

   Reconstruction - Route 18 and Apple Valley Road (08-SBd-18, PM 94.2/96.6)

   In the SB1 Project List, as of June 2018, under the Local Streets and Roads program, the following appears: Rt 18 West End Widening/Ph1 - Apple Valley Rd Realignment: Widening Route 18 from four to six lanes; realign and widening Apple Valley Road; modify existing drainage system; replace existing traffic signal; new retaining wall; curb and sidewalk improvements. $4,450,000.

   In February 2019, it was reported that Town Council action has restarted a decade-old road construction project at the intersection of Route 18 and Apple Valley Road. Council members approved a contract amendment on Jan. 22, 2019 for pre-construction work related to an overhaul of the intersection. The $491,366 amendment represents a not-to-exceed amount paid to Dokken Engineering for environmental and design services. The project is expected to widen the highway to six lanes, and Apple Valley Road to four lanes, among other improvements. The amendment increases Dokken’s total contract to more than $1.3 million for a combination of tasks that includes project management. The initial contract was approved Nov. 18, 2008, for a not-to-exceed amount of $417,000, town documents show. Dokken’s latest proposal had been in process for about a year and a half. A nearly $4.5 million California Transportation Commission grant and right-of-way acquisition from the state allowed for its consideration. Dokken completed 95 percent of the planning and design work between 2011 and 2014, but the project was put on hold in 2015 due to a lack of available funding for construction. The $4.5 million secured in 2018 through the CTC’s Local Partnership Program, created via passage of Senate Bill 1 in 2017, meant the project could again move forward. At the time, Town officials estimated a summer 2019 start for construction. But “all the environmental studies, all of the reviews, a lot of the water-quality regulations have changed” since 2014. In addition to widening Route 18 and Apple Valley Road, construction will eliminate Wika Road, a frontage road at the intersection’s northwest corner, according to a previous Daily Press report. Outer Highway 18 will be changed to a one-way road at the southeast corner. Grade changes along the roadway will be reduced, as well. Residents can also expect new traffic signals, storm drain installation, improved signage, retaining walls, additional crosswalks and sidewalks, among other upgrades. The project is currently valued at approximately 8 million, town documents show. Grant funds will be matched with San Bernardino County Transportation Authority Measure I funds and Apple Valley Transportation Impact Fees to cover costs. “It’s almost hard to imagine how complex this project will be and how hard it is to design,” according to the Town Manager. “This intersection is the busiest intersection in town. There are very few alternate routes, and the construction-phasing aspect of it is going to be trying to keep the number of lanes open that we have on a normal day during construction.”
   (Source: Victor Valley Daily Press, 2/5/2019)

   In May 2020, the CTC approved for future consideration of funding the State Route 18/Apple Valley Road Intersection Realignment Project (08-SBd-18, PM 94.2/96.6), which will widen and realign the Apple Valley Road Approach to the Route 18/Apple Valley Road Intersection in San Bernardino County. (PPNO 3010U). The project is located in the Town of Apple Valley on Route 18 in San Bernardino County. The objective of the project is to widen and realign the Apple Valley Road approach to the Route 18/Apple Valley Road intersection to reduce excessive vehicle delays and improve traffic operations. This project is fully funded and currently programmed in the 2018 Senate Bill 1 (SB 1) Local Partnership Program (LPP) for a total of $8,900,000 in LPP funds and Local funds. Construction is estimated to begin fiscal year 2019-2020. The scope, as described for the preferred alternative, is consistent with the project scope programmed by the California Transportation Commission (Commission) in the 2018 SB 1 LPP.
   (Source: May 2020 CTC Agenda, Agenda Item 2.2c.(1))

   In May 2020, the CTC approved the following STIP allocation: $4,450,000. 08-SBd-18 94.2/94.6. PPNO 08-3010U. ProjID 0818000194 EA 0G920. Route 18 West End Widening- Phase 1 Apple Valley Road Realignment. In the town of Apple Valley, at the intersection of Route 18 and Apple Valley Road. Widen Route 18, realign and widen Apple Valley Road, upgrade/modify existing drainage system, replace existing traffic signal and construct various sidewalk  improvements. Allocation: CONST $4,450,000.
   (Source: May 2020 CTC Agenda, Agenda Item 2.5s.(2))

   In August 2020, the CTC received notice of the following delegated allocation: $8,032,000. 08-SBd-18 97.0/99.5. PPNO 08-3006F ProjID 0813000140 EA 1E060. Route 18 In and near Victorville, from Amargosa Road to Cobalt Road. Outcome/Output: Improve safety by constructing raised curb median, widening roadway, and installing traffic signal. This project will reduce the number and severity of collisions.
   (Source: August 2020 CTC Agenda, Agenda Item 2.5f.(3) #8)

   Naming

   "Rim of the World" Highway; "North Shore" Drive; "Big Bear Blvd.", "Lakeview Dr." and "Paine Rd.".

   On Route 18 in San Bernardino County, at PM SBD 21.4, two miles south of the City of Rimforest, may be found the Donald S. Wieman Vista Point. It was named in honor of Donald S. Wieman, a native Californian (b. 1900), who was a skilled stone mason and building contractor in the Glendale, California area. He moved to San Bernardino in 1932 to work for the California Division of Highways and was responsible for constructing miles of red rock walls and other structures along Route 18, also known as the Rim of the World Highway. This masonry work was part of a major state public works program aimed at recovery from the Great Depression. He rose through the ranks of the Division of Highways to the position of Maintenance Superintendent, Special Crews, from which he retired in 1965. The historical marker reads as follows: "Donald S. Wieman / 1900 - 1977 / In 1932, during the Great Depression, California launched a large public works project to aid recovery. A major component was the construction of masonry walls, parapets and fountains along the historic "Rim of the World" highway. This work, widely acclaimed for its beauty and craftsmanship, was the handiwork of Donald S. Wieman. This vista point is dedicated to his memory." Named by Assembly Concurrent Resolution 248, Chapter 195, September 16, 2004.
   (Image source: Historical Marker Database)

   The segment of this route in the County of San Bernardino, beginning at the intersection of Route 18 and Route 330 and continuing toward Big Bear Lake for 4.5 miles (~ SBD 31.548 to SBD 36.048), is designated the "Rim of the World Veterans Memorial Highway". It was named in honor of the nearly two million veterans that reside in the State of California, and particularly those veterans who live in the San Bernardino Mountains. The naming was spearheaded by the American Legion Post 360 and the Veterans of Foreign Wars Post 9624, who partnered to sponsor the “Rim of the World Veterans Memorial Highway” designation in honor of those who have dedicated their lives to the service of this nation. Named by Assembly Concurrent Resolution (ACR) 21, Res. Chapter 87, Statutes of 2015, on July 1, 2015.
   (Image source: Alpenhorn News)

   The segment of this route in the City of Apple Valley (~SBD 86.844 to SBD 95.395) is officially named the "Happy Trails Highway". It was named by Assembly Concurrent Resolution 82, Chapter 80, in 1992. Happy Trails was the song and slogan made famous by Roy Rodgers and his wife, Dale Evens, both residents of Apple Valley. More information on Roy Rodgers can be found at the Roy Rodgers-Dale Evens Website. The Roy Rodgers Museum was located in Victorville, CA, until March 2003.

   Business Routes

   This route appears to have a business route on Sierra Way in San Bernardino, N of Route 210. Cameron Kaiser reports that, as of May 2009, Business Route 18, appears to be quite alive. There has been some evidence of sign replacement on Sierra Way, including a brand-new Rourte 18 and BUSINESS banner just past the bridge at Sierra and 30th.

   The old routing of Route 18 through the Village in Big Bear is signed both officially and unofficially as Business Route 18.

   Scenic Route

   [SHC 263.3] From Route 138 near Mt. Anderson to Route 247 near Lucerne Valley.

   Although this segment is eligible for Scenic Highway status, it has not yet met the criteria to be officially designated as Scenic Highway.

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3. From Route 15 near Victorville to Route 138 near Pearblossom.

   Post 1964 Signage History

   ▸In 1963, this segment was part of the larger Route 18 that ran "from Route 10 near San Bernardino to Route 138 via San Bernardino, near Mountain View Avenue and via Waterman Canyon, Big Bear Lake, Baldwin Lake, and near Victorville." This definition was relaxed in 1965 to "Route 10 near San Bernardino to Route 138 via San Bernardino, Waterman Canyon, Big Bear Lake, Baldwin Lake, and near Victorville."

   Scott Parker on AARoads noted: The western extension of Route 18 from I-15 to Route 138 in L.A. County was, prior to its adoption into the state highway system in late '67, a well-used county facility. Bringing that road into the system at that particular time was prompted by Southern Pacific's construction of their Palmdale-Colton "cutoff" line enabling freight traffic to bypass central L.A. The tracks would have crossed that road at a very sharp angle, generally considered the most dangerous crossing type; San Bernardino County was reluctant (and short of available funds) to pay for a road overpass, so they petitioned the Division of Highways to adopt the road; it was close to the unadopted Route 18 extension—but at the time the Division preferred a new-terrain alignment a bit to the north of that road. But the county was persistent, so in late 1965 the Division "caved" and agreed to take the road into the system and construct an overpass over the new SP line. When the bridge was completed in the fall of '67, the adoption was formalized. But even then signage was sporadic, mostly clustered at I-15 and Route 138 as well as the US 395 "crossroads" in west Victorville; reassurance shields were, for the most part, absent apart from those junctions.
   (Source: Scott Parker on AARoads, "Re: CA 18", 10/2/2019)

   ▸In 1984, Chapter 409 split the definition into two parts: (a) Route 10 near San Bernardino to Route 15 via San Bernardino, Big Bear Lake, and Victorville. (b) Route 15 to Route 138.

   ▸In 1986, Chapter 928 tightened the language for this segment: "Route 15 near Victorville to Route 138 near Pearblossom."

   This segment was planned as freeway in 1965; never upgraded. It may be part of the High Desert Corridor.

   Pre 1964 Signage History

   This segment was not signed as part of Route 18 until 1967. It was LRN 268, and was defined in 1959. It wasn't constructed until after 1967.

   Status

   In April 2019, it was reported that construction on a new raised curb median along Palmdale Road (Route 18) between Cobalt Road in Victorville and US 395 (~ SBD 99.451 to SBD 100.984) was starting in May 2019. The $15 million project will construct a raised curb median and include the reconfiguration of left turn pockets to enhance safety and help eliminate cross-median collisions. The project is expected to be complete in summer 2020. Weather conditions may affect the completion date of this project. Construction on the project began 7/15/2019
   (Source: Victorville News, 4/24/2019; CaltransCommuter Alert, 7/3/2019)

   In March 2026, the CTC adopted the 2026 STIP, which included the following as new programming: PPNO 08-2863J, “Rt 18 Corridor Freight and Safety Improvements” (08-SBd-18 100.900/115.900). Total Programmed ($×1000): $9,927. 2026 and Future Programming ($×1000): $9,927 FY29-30. Programming Breakdown ($×1000): $0 (PA&ED), $0 (PS&E), $9,927 (Const), $0 (Con Sup), $0 (R/W), $0 (R/W Sup). The Route 18 Corridor Freight and Safety Project proposes to enhance a 15-mile corridor of Route 18 for the San Bernardino County portion, from the Los Angeles/San Bernardino County line to US 395 near Victorville. Phase 1 of the project will be located on Route 18 from Smith Road to US 395. The project includes operational, safety, and complete streets upgrades including the addition of a center striped median and left/right turn lanes at key intersections. No new through lanes are being proposed. The project also includes roadway reprofiling, a truck charging station at the east end, new bicycle facilities, signal modifications, and resilience upgrades and route redundancy. In addition, a ZE charging station with a capacity of 4.8 Mega Watts will be proposed.
   (Source: March 2026 CTC Agenda, Agenda Item 4.4; 2026 STIP Staff Recommendations Adopted 2/27/2026)

   Route 18 Rumble Strip Project (08-SBd-18, PM 101.5/115.9)

   In March 2018, a Draft EIR was released for a proposed safety project to widen the shoulders and install rumble strips on Route 18. The project would occur between SBD 101.5 in the City of Adelanto (0.5 mi W of US 395) and SBD 115.9 on the northern edge of unincorporated Pinon Hills (this is the LA County Line, near the point where Route 138 and Route 18 meet). The eastern 2.4 miles of this highway segment are located within the City of Adelanto and the remaining 12.0 miles of this roadway segment is situated within unincorporated San Bernardino County. The project proposes to build a 4 foot median buffer, widen existing shoulders to 8 feet, and add centerline and shoulder rumble strips to both sides of the roadway. The project will also replace existing dikes, install new guardrail as necessary, and extend or replace existing culverts. The purpose of the proposed project is to warn and/or alert distracted motorists about the imminent potential for crossing the centerline into oncoming traffic and/or crossing onto the shoulder. The centerline rumble strip and shoulder rumble strip will generate an audible noise and rumble effect when tires pass over it to warn drivers to take corrective action to bring the vehicle back in the lane. Replacing the existing pavement markers and re-striping will enhance the visibility and delineation of the pavement. The proposed project is expected result in a reduction of cross-centerline and run-off road collisions along this segment of Route 18. The purpose of the proposed project is also to upgrade the existing shoulders to comply with the Caltrans Highway Safety Improvement Guidelines (CHSIG). The annual average daily traffic on Route 18 (2013) is 8,600. The opening year (2020) traffic is 8,900 and year 2040 traffic is expected to reach 10,000.
   (Source: Route 18 Initial Study with Proposed Mitigated Negative Declaration, March 2018)

   In August 2018, the CTC approved for future consideration of funding the following project for which a Mitigated Negative Declaration (MND) has been completed: Route 18 in San Bernardino County (08-SBd-18, PM 101.5/115.9). Construct roadway improvements to a portion of Route 18 near the city of Adelanto. (PPNO 0191G) This project is located on Route 18 in and near the city of Adelanto in San Bernardino County. The project proposes to widen shoulders and add centerline and shoulder rumble strips. This project is expected to reduce the incidence and severity of cross centerline accidents. The proposed project is estimated to cost $49.0 million. This project is fully funded and is currently programmed in the 2016 SHOPP for approximately $48.5 million which includes Construction (capital and support) and Right-of-Way (capital and support). The project is estimated to begin construction in funding Fiscal Year 2018-19. The scope, as described for the preferred alternative, is consistent with the project scope programmed by the Commission in the 2016 SHOPP.
   (Source: August 2018 CTC Agenda Item 2.2c(1))

   In August 2018, the Department allocated $28,848,000 to the following SHOPP project: San Bernardino 08-SBd-18 101.5/115.9. Route 18 In and near Adelanto, from 0.5 mile west of Route 395 to 0.9 mile west of Oasis Road. Outcome/Output: Widen shoulders and add centerline and shoulder rumble strips. This project will reduce the number and severity of collisions.
   (Source: October 2018 CTC Agenda Item 2.5f.(3) Item 9)

   In July 2019, Caltrans advised that they were beginning a safety operation on Route 18 in and near the city of Adelanto from the US 395 junction to 263rd East Street. This project will include the widening of existing shoulders to state standards and the installation of center line and shoulder rumble strips.
   (Source: Caltrans Commuter Alert, 7/1/2019)

   In June 2021, it was reported that the CTC approved $16.35 million for pavement rehabilitation along Route 18 from Adelanto to the Los Angeles County line (~ SBD 100.968 to SBD 115.9). Normally pavement rehabilitation doesn't make it into these pages, but this stretch really needed it. It had gotten so bad that drivers were detouring up Route 14 to Mojave, and going across Route 58 to Barstow.
   (Source: Victorville Daily Press, 6/29/2021)

   In March 2016, the CTC approved additional funding for a project located in Los Angeles County on Route 18, near the city of Palmdale (a bit W of the Route 138 junction), at Overhead No. 53-2331 (LA 000.19). It will replace the bridge deck, joint seals and bridge railing.

   Widen Conventional Highway (Segment 13) (PPNO 4357) of Route 138 Widening (07-LA-18 3.396/4.396)

   (March 2015) Segment 13 is programmed in the STIP for $43,900,000 and will widen approximately four miles on Route 138 from just west of 190th Street East to the Route 138/Route 18 Separation and one mile on Route 18 from the Route 138/Route 18 Separation (~ LA 4.396) to one mile east of the Route 138/Route 18 Separation (~ LA 3.396). The R/W phase will begin in Fiscal Year 2015-16 and is funded with $6,000,000 from RIP and $1,000,000 from Local RSTP. The R/W estimate for this segment has increased by $3,500,000 due to the need to acquire additional parcels for drainage as well as additional utility relocation costs. The Department proposes to increase the RIP programming for R/W from $6,000,000 to $9,500,000. The construction phase is funded with $31,400,000 from RIP and $4,600,000 from Local RSTP. During the design phase, the Department identified the need to add an additional passing lane at the connector of eastbound Route 138 to eastbound Route 18 to improve safety and operations. This revision to the design increased the construction estimate by $4,000,000. The Department proposes to increase the RIP programming for construction capital from $31,400,000 to $35,400,000. Segments 6 and 13, are currently programmed in the 2014 STIP for delivery in Fiscal Year 2016-17. In March 2015, a STIP amendment adjusted the funding for Segments 6 and 13

   The 2018 STIP, approved at the CTC March 2018 meeting, appears to provide a bunch of allocations for the different segments of this project. PPNO 4357, Widening Segment 13, 190^th St E - Rt 18, has its funding restored and brought up to $80,500K, with construction in FY22-23.

   In March 2020, the CTC approved the 2020 STIP, which changed the name of PPNO 4357 "Widen 4-lanes, Segment 13, 190^th St E-Rt 18" to "Widen 4-lanes, Segment 13, 190th St E-213 St E", and adjusted the programmed funding from $80,500K to $62,100K.
   (Source: March 2020 CTC Agenda, Item 4.7, 2020 STIP Adopted 3/25/2020)

   In March 2023, the CTC was given notice of, and in May 2023, the CTC approved, an amendment to the 2022 SHOPP that revises the scope and funding plan for two Route 138 Corridor STIP projects, in Los Angeles County, per STIP Guidelines as follows: (1) The Widen Conventional Highway (Segment 4) (PPNO 4353) project proposes to (1a) amend the project scope to provide multimodal transportation access; (1b) change the project name to “Multimodal Mobility Improvements (Segment 4)” and (1c) deprogram $13,000,000 of the $20,000,000 programmed of Regional Improvement Program (RIP) funding from the Construction phase in Fiscal Year 2024-25; (2) the Widen Conventional Highway (Segment 13) (PPNO 4357) project proposes to (2a) increase project scope by increasing post mile limits and (2b) program an additional $13,000,000 of RIP funds which brings the Construction phase from $40,300,000 to $53,300,000 in Fiscal Year 2023-24. The Multimodal Mobility Improvements (Segment 4) project (PPNO 4353), previously named the Widen Conventional Highway, was originally programmed in the 2018 STIP for the Plans, Specifications and Estimates (PS&E), Right of Way (RW) and Construction (CON) phases and was carried over into the 2020 and 2022 STIPs.  The original scope of work consists of widening the Route 138 conventional highway from two lanes to four lanes between postmile (PM) 53.1 to 54.3.  In August 2020, a community outreach meeting was held that garnered disgruntlement from the Littlerock community because they liked the rural feel of the town, as with the number of lanes, it encourages vehicles to drive slower and stop at local businesses.  The community felt with the widened lanes, vehicles may drive through faster, which raises high speed concerns and potentially economic ones as its possible customers would not stop at local businesses. In addition, a number of parcels are needed for the project for right-of-entry permits for hazardous waste testing that is required. This is proving difficult to do as some of the property owners are either deceased or live out of state. With this in mind, Caltrans reevaluated and pivoted to have a multimodal approach for this project, and updated the scope and presented it to the Littlerock town council and residents in October 2022, who were all in support of this alternative. Therefore, the Department and LA Metro proposed to amending the project to provide multimodal improvements and enhance safety by eliminating the original scope of widening the highway to two lanes in each direction. The project name was changed to Multimodal Mobility Improvements (Segment 4), and the description was updated to match the revised scope which now includes installation of sidewalks, curb ramps, traffic calming measures, a traffic signal at 77th Street East, drainage improvements, and bike lanes.  In addition, cost savings of $13,000,000 for construction, from $20,000,000 to $7,000,000, have been realized due to the revised scope change. The Route 138 Widening (Segment 6) project (PPNO 4356) is within the same corridor and has been completed with cost savings of $5,000,000 in Regional Surface Transportation Program (RSTP) funds. The Widen Conventional Highway (Segment 13) project (PPNO 4357) is programmed in the 2022 STIP for the PS&E, RW and CON phases. The current scope of work for this consists of widening the Route 138 conventional highway from two lanes to four lanes between PM 66.0 to 70.1, and on Route 18 between PM 3.4 to 4.5.  However, in March 2022, when the increase to the project limits of the Widen Conventional Highway (Segment 13) project (PPNO 4357) was approved, the corresponding cost increase needed for construction was not included, as the project had just begun the design phase and the revised estimated costs were unknown.  The project has now completed 60 percent review, and a more accurate cost estimate is available that shows construction cost increased by $18,000,00 to $58,300,000. This additional $18,000,000 being requested for Widen Conventional Highway (Segment 13) (PPNO 4357) project will come from the Regional Improvement Program (RIP) and RSTP cost savings from the two other projects (PPNO 4356 and 4357) within the same corridor. This amendment proposes to deprogram $13,000,000 of RIP funds for construction in Fiscal Year 2024-25 from the Multimodal Mobility Improvements (Segment 4) project (PPNO 4353) and reprogram these funds for construction in 2023-24 for the Widen Conventional Highway (Segment 13) project (PPNO 4357), in Los Angeles County.
   (Source: March 2023 CTC Agenda, Agenda Item 2.1b.(3); May 2023 CTC Agenda, Agenda Item 2.1a.(4))

   In December 2025, the CTC approved for future consideration of funding the following project for which a FEIR and Addendum have been completed: SR-138 Widening Project (Segment 13): Route 138 and Route 18 in Los Angeles County. Widen Route 138 from PM 66.0 to 68.5 from 2 lanes to 4 lanes, consisting of two 12-foot lanes and an 8-foot shoulder in each direction divided by a 16-foot two way left-turn median, creating additional capacity. Additionally, provide traffic striping improvements only (no additional capacity) on Route 138 from PM 68.5 to 70.1 and Route 18 from PM 3.4 to 4.5, in Los Angeles County. (PPNO 07-4357) The project plans to widen Route 138 from Avenue T in Palmdale through the communities of Littlerock, Pearlblossom, and Llano to the Route 18 junction. This project consists of adding an additional 12-foot lane in both directions, a 16-foot median, and 8-foot shoulders within the project area in order to upgrade the current facility to a conventional highway. The project was split into 13 segments. The project is currently programmed in the 2022 State Transportation Improvement Program (STIP). The total programmed amount, which includes Right of Way (Support and Capital) and Construction (Support and Capital) is $90,600,000, which includes the Regional Improvement Program. Construction will begin in 2025-26. The scope, as described for the preferred alternative, is consistent with the project scope as programmed by the Commission in the 2022 STIP.  The Commission accepted the FEIR and approved the project for future consideration of funding on June 6, 2001 under Resolution E-01-28. Since the approval of the FEIR, there have been changes to the project and an Addendum was prepared pursuant to CEQA. Specifically, the Addendum addresses minor design modifications including a reduction in capacity increasing highway widening to a portion of the Segment 13 alignment (on Route 138 from PM 66.0 to 68.5) instead of the entire segment as originally proposed. The remainder of the segment on Route 138 from PM 68.5 to 70.1 and Route 18 from PM 3.4 to 4.5 will retain its existing roadway width and include traffic striping improvements only (no additional capacity). Further, bicycle lanes have been removed from the project scope. Conclusions of the FEIR remain applicable. In accordance with CEQA Guidelines Section 15162, no Subsequent FEIR is required for the project because new information and changes in circumstances, project description, impacts, and mitigation are not substantial and do not involve new significant impacts or a substantial increase in the severity of previously identified impacts. As a result, the Department completed an Addendum to the FEIR pursuant to CEQA. The Department has approved this project for construction. This approval and the Addendum will satisfy the environmental requirements for this stage of the planning process. [Ed: Note bolded section, added for highlighting. This is a significant change in this segment, despite it being called a "minor design modification".].
   (Source: December 2025 CTC Agenda, Agenda Item 2.2c.(4) #04)

   In December 2025, the CTC approved an allocation of $55,206,000 for the State-Administered STIP Widen Conventional Highway (Segment 13) project (PPNO 07-4357): $55,206,000. 07-LA-138 66.0/70.1; 07-LA-18 3.4/4.5. PPNO 07-4357; ProjID 0713000216; EA 28630. Widen Conventional Highway (Segment 13). In Llano, on Route 138 from 0.4 miles west of 190^th Street east to 0.7 mile south of the Route 138/Route 18 Junction and on Route 18 from the Route 138/Route 18 Junction to 1.1 mile east of the junction. Widen conventional highway from 2 lanes to 4 lanes. CEQA - EIR, 03/29/2021; Re-validation 09/18/2025. NEPA - FONSI, 11/30/2023; Re-validation 09/18/2025. Future consideration of funding approved under Resolution E-01-28; March 2001. Concurrent addendum for the previously approved future consideration of funding under Resolution E-25-77A; December 2025. Right of Way Certification: 10/13/2025. Time Extension for FY 23-24 CONST expires 12/31/2025. The additional funding need of $1,906,000 will come from the R/W phase savings. Allocation: CON ENG $7,800,000; CONST $45,500,000 $47,406,00.
   (Source: December 2025 CTC Agenda, Agenda Item 2.5c.(1))

   Naming

   This route is named "Palmdale Road".

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Freeway

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Interregional Route

Pre-1964 Legislative Route

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Acronyms and Explanations:

• "LRN" refers to the Pre-1964 Legislative Route Number. "US" refers to a US Shield signed route. "I" refers to an Eisenhower Interstate signed route. "Route" usually indicates a state shield signed route, but said route may be signed as US or I.
• Previous Federal Aid (pre-1992) categories: Federal Aid Interstate (FAI); Federal Aid Primary (FAP); Federal Aid Urban (FAU); and Federal Aid Secondary (FAS). Current Functional Classifications (used for aid purposes): Principal Arterial (PA); Minor Arterial (MA); Collector (Col); Rural Minor Collector/Local Road (RMC/LR). Note that ISTEA repealed the previous Federal-Aid System, effective in 1992, and established the functional classification system for all public roads.
• Other frequently used terms: California Transportation Commission (Commission or CTC), California Department of Transportation (Department or Caltrans), Regional Improvement Program (RIP), Interregional Improvement Program (IIP), State Transportation Improvement Program (STIP), State Highway Operation and Protection Program (SHOPP), Traffic Congestion Relief Program (TCRP), Clean Air and Transportation Improvement Act of 1990 (Proposition 116), High Speed Passenger Train Bond Program (Proposition 1A), Highway Safety, Traffic Reduction, Air Quality, and Port Security Bond Act of 2006 (Proposition 1B), Corridor Mobility Improvement Account (CMIA), State Route 99 Bond Program (RTE or SR 99), Local Bridge Seismic Retrofit Account (LBSRA), Trade Corridors Improvement Fund (TCIF), Highway-Railroad Crossing Safety Account (HRCSA), State-Local Partnership Program (SLPP), Environmental Phase (PA&ED), Design Phase (PS&E), Right of Way (R/W), Fiscal Year (FY), Active Transportation Program (ATP), Trade Corridor Enhancement Program (TCEP), Local Partnership Program (LPP), Local Streets and Roads Program (LSRP), Solutions for Congested Corridors Program (SCCP).

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