US 399 Bakersfield

[Mapmikey]

So, I am working on the US 399 entry for the website to update/continue the old Droz site
http://www.vahighways.com/usroute/index.htm

Everything I see written about US 399 online is that it didn't originally end in Bakersfield but instead at Greenfield until it was extended in 1936.  I believe this is incorrect, as the mileage in its original AASHO log from Taft to Bakersfield is 37 miles, which has to take it to central Bakersfield.

There is also a July 1935 map in the AASHO database from the state explicitly showing the 99-399 duplex.

The next part of my question is there is a 1935 map that shows 399 going from Panama to Bakersfield up Stine Rd then a few turns near Bakersfield.  My question is whether it is possible 399 did this solo part briefly at its beginning before being rerouted to Greenfield.   One piece of counterevidence is the 1934 Kern County map does show some of that solo routing as secondary.

Is there absolute proof US 399 always used US 99 from the start?

 

[cahwyguy]

I'll do my best to monitor this, but please let me know if you uncover stuff I need to work into my US 399 or CA 33 pages at www.cahighways.org.

[pderocco]

What I don't get is why 399 multiplexed with 99 at all. It's not as though it ever existed independently east of 99.

[Mapmikey]

What I don't get is why 399 multiplexed with 99 at all. It's not as though it ever existed independently east of 99.

It was common practice in the early years of the US route system to extend a route into the center of the city if it terminated nearby.  Some states got rid of these useless duplexes much faster than others.

[Max Rockatansky]

To my knowledge 399 always followed 99 to 466.  I'll have to dig up what I found 399 in the AASHTO database when I get inside from yard work.

[pderocco]

To my knowledge 399 always followed 99 to 466.  I'll have to dig up what I found 399 in the AASHTO database when I get inside from yard work.

I can see you standing there with your rake and your phone.

[Road Hog]

What I don't get is why 399 multiplexed with 99 at all. It's not as though it ever existed independently east of 99.

It was common practice in the early years of the US route system to extend a route into the center of the city if it terminated nearby.  Some states got rid of these useless duplexes much faster than others.

Not Texas. US 380 for example duplexes with US 69 in Greenville all the way to I-30, even though US 380 does not extend further.

Arkansas did the same with AR 21, extending it south in Clarksville to I-40 even though AR 21 more properly terminates at US 64 through town.

[Max Rockatansky]

To my knowledge 399 always followed 99 to 466.  I'll have to dig up what I found 399 in the AASHTO database when I get inside from yard work.

I can see you standing there with your rake and your phone.

Shovel pushing up brick tonight. Anyways, the original September 1934 definition had US 399 as US 101 to US 99.  The thing that makes me think 399 always ended at 466 is that the description says "Bakersfield" and not "near Bakersfield."  The original definition is on this page on photos 16 and 17:

https://www.gribblenation.org/2018/07/california-state-route-33-us-101-north.html?m=1

[usends]

It was common practice in the early years of the US route system to extend a route into the center of the city if it terminated nearby.

I agree, and this probably happened more often than we realize (because most maps were too small-scale to illustrate the overlaps).  However, as more and more historic photos surface on the internet, we see numerous examples of route designations that were signed into the city center (often to a courthouse or other gov't building).

[The Ghostbuster]

I would have liked it if CA 33 south of Taft, and all of CA 119 had been numbered CA 399 upon US 399's decommissioning. After all, when US 299 was decommissioned, they left all of it as CA 299.

[Max Rockatansky]

I would have liked it if CA 33 south of Taft, and all of CA 119 had been numbered CA 399 upon US 399's decommissioning. After all, when US 299 was decommissioned, they left all of it as CA 299.

And truncate CA 166 to Cuyama Junction.  CA 33 ending at Mettler always more sense to me since the corridor largely mirrors I-5 in the Central Valley. 

[Mapmikey]

Anyways, the original September 1934 definition had US 399 as US 101 to US 99.  The thing that makes me think 399 always ended at 466 is that the description says "Bakersfield" and not "near Bakersfield."  The original definition is on this page on photos 16 and 17:

https://www.gribblenation.org/2018/07/california-state-route-33-us-101-north.html?m=1

Thanks...


So we agree on the first part of my post.

The 1935 Gousha map on that blog also shows 399 going to Bakersfield with no US 99 overlay.

[Max Rockatansky]

Anyways, the original September 1934 definition had US 399 as US 101 to US 99.  The thing that makes me think 399 always ended at 466 is that the description says "Bakersfield" and not "near Bakersfield."  The original definition is on this page on photos 16 and 17:

https://www.gribblenation.org/2018/07/california-state-route-33-us-101-north.html?m=1

Thanks...


So we agree on the first part of my post.

The 1935 Gousha map on that blog also shows 399 going to Bakersfield with no US 99 overlay.

Yes, I think there are some missing docs from the 1934 file.  There is a lot of missing information for 299 and 395 that usually is present.  Most the Division of Highways applications had pretty detailed maps.

[Mapmikey]

I'll do my best to monitor this, but please let me know if you uncover stuff I need to work into my US 399 or CA 33 pages at www.cahighways.org.

I have completed the entry - http://www.vahighways.com/usroute/us399.htm

I was not able to prove/disprove whether US 399 went solo into Bakersfield initially.  I believe the time it might've done that was so short that it is extremely unlikely it was posted that way.

I tried to do my own research before going through your site and the Gribblenation blogs on US 399.  Both of you go into far more detail than is possible for my attempt to document all the US routes to an extent greater than the Droz site.

What I didn't see much of on your sites is the endpoint in Ventura.  I think everybody I saw elsewhere has the original endpoint incorrect and nobody mentions the final endpoint.  US 101 by 1934 was using Main/S Garden/Thompson.  Later, the Ojai Freeway actually first ended at Main/S. Garden using an arterial that was removed in the 1980s.  The Ojai didn't reach the US 101 Freeway until after US 399 was gone.

[ClassicHasClass]

If it went up Stine Rd, it looks like much of that was obliterated north of the New Stine Rd split. There is a little fragment of it SW of the shopping centre at California and CA 99, so I'm guessing it would have then gone across California Ave to Union Ave since US 99 should have been off Chester by then?

However, if we think the Gousha map suggests it crossed then-CA 178 first before getting to US 99, then there aren't very many remaining candidates for the old alignment.

[Max Rockatansky]

The realignment of US 99 was complete by June 1934.  However, the movement of the highway wasn't exactly straightforward while Golden State Avenue was being constructed:

https://www.gribblenation.org/2017/12/california-state-route-204-former-us-99.html?m=1

Regarding the Ojai Freeway I'll have to look at what is missing.  I probably ought to do something standalone since the existing blog had a huge emphasis on Maricopa Highway.

[Mapmikey]

If it went up Stine Rd, it looks like much of that was obliterated north of the New Stine Rd split. There is a little fragment of it SW of the shopping centre at California and CA 99, so I'm guessing it would have then gone across California Ave to Union Ave since US 99 should have been off Chester by then?

However, if we think the Gousha map suggests it crossed then-CA 178 first before getting to US 99, then there aren't very many remaining candidates for the old alignment.

1934 Bakersfield inset shows Chester to Brundage to Oleander
1935 Kern County shows Stine to Stone (no longer continuous) to Wilson to Wible.

My best guess was Bell Terrace between Wible and Oleander.

The realignment of US 99 was complete by June 1934.  However, the movement of the highway wasn't exactly straightforward while Golden State Avenue was being constructed:

Worst case, the July 1935 state map explicitly shows 99-399 overlay...

[Max Rockatansky]

The problem is that the Division of Highways published state maps every other year.  The 1936 city insert shows the 99/399 multiplex.  I'm aware Gousha published a California map in 1935 but it lacks anything detailed for Bakersfield.

The Division of Highways published county maps in 1935 which were based off 1934 data (they lack sign route designations).  Stine is shown to be a major Kern County highway but not State Highway:

https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~247291~5515356:Kern-County-?sort=Pub_List_No_InitialSort%2CPub_Date%2CPub_List_No%2CSeries_No&mi=0&trs=1&qvq=q:Kern%20county%201935;sort:Pub_List_No_InitialSort%2CPub_Date%2CPub_List_No%2CSeries_No;lc:RUMSEY~8~1

[cahwyguy]

What I didn't see much of on your sites is the endpoint in Ventura.  I think everybody I saw elsewhere has the original endpoint incorrect and nobody mentions the final endpoint.  US 101 by 1934 was using Main/S Garden/Thompson.  Later, the Ojai Freeway actually first ended at Main/S. Garden using an arterial that was removed in the 1980s.  The Ojai didn't reach the US 101 Freeway until after US 399 was gone.

This prompted me to go do an update on my site. Working off the USGS Topoview ( https://ngmdb.usgs.gov/topoview/viewer/#17/34.34895/-119.29938 ), 1941 map, as well as the 1951 maps. Here's what I came up with:

Signage of the route as US 399 dates back to around 1935.

Prior to the Ojai Freeway, US 399 (possibly co-signed with Sign Route 150) started at US 101 (Thompson Blvd) and S Ventura Avenue. It continued N up Ventura Avenue in Ojai, to a junction with Baldwin Avenue, where it met Sign Route 150 entering from the W.

A digression: Sign Route 150 appears to have been an interesting hydra in the area, meaning that there were multiple roads signed as Sign Route 150. The main route—that is, the one that appears to correspond with the state highway map—entered from the Santa Barbara area along Casitas Pass Road. As it neared the lake approaching from the W, it made a horseshoe turn and proceeded to cross the lake along a route that is now underwater, veering N to meet Baldwin Road near the SB Santa Ana Road connection. Sign Route 150 then followed Baldwin Road (and Old Baldwin Road) to meet Ventura Avenue. But the USGS maps also show other routes signed as part of Sign Route 150: Notably, a connection (again, now underwater) to Casitas Vista Road that continued to meet Ventura Road, where it continued S into Ventura as a US 399/Sign Route 150 cosign. Sign Route 150 split off to the W at Casitas Vista Road (nee Casitas Pass Road); however, that route was later obviated by the filling of Lake Casitas. The pre-lake Sign Route 150 met another road that is now also underwater, continuing to the NE to about where Santa Ana Road is. where it met today's Route 150 at Baldwin Road. That same USGS map also shows Sign Route 150 running from the Ventura Road/Santa Ana Road junction along Santa Ana Road and Burnham Road to Baldwin Road. However, it is clear that Sign Route 150 shared US 399 between Baldwin Road and Ojai Avenue, split back off on its lonesome to the E along Ojai Avenue as solely Sign Route 150.

After the Ojai Freeway was constructed, the routing in Ventura changed. By 1951, US 399 was using a connector that started near N. Thompson and Main (US 101) near N Garden, which went diagonally to pick up the Ojai Freeway near Park Row Avenue (Note that S. Garden was the US 101 connector between Thompson and W Main before the freeway). That connector was modified with the construction of the Mission Plaza Shopping Center; it now starts off of N Olive below Rex Street, providing accessibility to the Ojai Freeway (now Route 33, nee US 399) from W. Main (which was US 101). After the freeway portion of the Ojai Freeway ends (see the page on Route 33), the road downgrades into Ventura Avenue.

Between Baldwin Avenue and Ojai Avenue, US 399 was co-signed with Sign Route 150. Sign Route 150 split off at Ojai Ave, and US 399 continued along Maricopa Avenue to a point E of Cuyama Ranch, where it met Sign Route 166 and continued co-signed to the NE (this is today a Route 33/Route 166 cosign, legislatively Route 33) into Maricopa. In Maricopa, Sign Route 166 continued to the E along Maricopa Highway, while US 399 continued (potentially cosigned with Sign Route 33) N along California St. This later became today's West Side Highway; it is unclear the former name of the road. Within Taft, US 399 split from Sign Route 33 at Kern Street and Harrison, with Sign Route 33 continuing NW along Kern, and US 399 continuing along 6th Street/Harrison. Today, US 399's replacement, Route 119, veers off the West Side Highway/Kern Street at Taft Highway. Harrison (the old alignment) and Taft Highway (the new alignment) merge just N of the town of Taft. Note that Harrison Street continues NE after the first merge to meet Taft Highway again, at a point E of Elk Hills Road; that portion of Harrison Street was the original US 399 prior to the Taft Highway realignment.

Near the N Coles Oil Field, US 399 originally veered off along today's Golf Course Road and Tupman Road (now Golf Course Road, until it crosses Taft Highway and becomes Tupman again). That loop was cutoff by the construction of Taft Highway. US 399 continued along Taft Highway into Greenfield, where it met US 99.

Supposedly, as of 1936, US 399 actually continued north cosigned with US 99 to end at US 466. However, this is not shown on the 1941 USGS map. This portion of US 399 was later relegated to Business Loop status in 1962, and became BR 99/Route 204 in 1964. However, the portion of former US 399 south of Brundage Lane (current parallel street to Route 58, the replacement for US 466) was removed from the state route in 1978; only the portion of former US 99 on Union Avenue from Golden State Avenue/Sumner Street south to Route 58 remains in the state system as Route 204. All of the route remains part of BR 99.

I'll continue doing updates based on what you found (giving you credit, and adding in links to your US highway page on US 399). I'll also be updating the information regarding Sign Route 150 and the relationship to US 399 in the Ojai area. Thanks.

[Mapmikey]

Note that the original piece of Ojai Freeway that used the diagonal connection opened Dec 1956, not by 1951. 

[Max Rockatansky]

The years on those USGS maps I've found aren't exactly 100% accurate.  I find things on some early map editions that I know for sure didn't yet exist.  For example, it is easy to find Sign Route designations for the Sierra Nevada foothills that are listed as 1920s era maps.

[The_Ginger]

The years on those USGS maps I've found aren't exactly 100% accurate.  I find things on some early map editions that I know for sure didn't yet exist.  For example, it is easy to find Sign Route designations for the Sierra Nevada foothills that are listed as 1920s era maps.

At times the "Revised" year is hard to find.

[Max Rockatansky]

The years on those USGS maps I've found aren't exactly 100% accurate.  I find things on some early map editions that I know for sure didn't yet exist.  For example, it is easy to find Sign Route designations for the Sierra Nevada foothills that are listed as 1920s era maps.

At times the "Revised" year is hard to find.

The strips those maps are divided up into make it next to impossible to find on the viewer.  For state highway stuff in California I've always found it most accurate to go with what the Division of Highways published.

[cahwyguy]

The years on those USGS maps I've found aren't exactly 100% accurate.  I find things on some early map editions that I know for sure didn't yet exist.  For example, it is easy to find Sign Route designations for the Sierra Nevada foothills that are listed as 1920s era maps.

At times the "Revised" year is hard to find.

The strips those maps are divided up into make it next to impossible to find on the viewer.  For state highway stuff in California I've always found it most accurate to go with what the Division of Highways published.

But often, the division of highways map aren't at the right level of detail or don't label roads or highways. Using the transparency sliders on the USGS maps is very useful to determine routes; it is poor to determine specific years of changes. I find the USGS maps useful; I just wish there were more years in their database.

I've done another pass at everything (and found a few error's in Mapmikey's pages, including some typos and unclear sentences). My reworked version is:

In the CHPW announcing the 1934 signage of routes, the route that would become US 399 is shown with a US highway shield, but no specific number, and only runs as far as the junction with LRN 57 (Sign Route 166). That map does not show US highway signage on the route into Bakersfield. "399" is not included on the list of routes in that issue, as the list only covers state sign routes.

Signage of the route as US 399 dates back to around 1935.

Prior to the Ojai Freeway, US 399 (possibly co-signed with Sign Route 150) started at US 101 (Thompson Blvd) and S Ventura Avenue. It continued N up Ventura Avenue in Ojai, to a junction with Baldwin Avenue, where it met Sign Route 150 entering from the W. There are some reports* that US 399 may have used Nye Road in Casitas Springs; and Sulphur Mtn Rd, and abandoned loop and/or Creek Rd, or Old Grade Rd in the Oakview area. It it did, that usage ended by 1936. Note that there is also a section of Old Ventura Ave starting at Park Ave in Ojai; that is likely an older routing.
(Source: *Mapmikey: The Virginia Highways Project: US Highways: Histories for Mainline, Suffixed, and Bannered Routes: US␠399)

A digression: Sign Route 150 appears to have been an interesting hydra in the area, meaning that there possibly were multiple roads signed as Sign Route 150. The main route—that is, the one that appears to correspond with the state highway map—entered from the Santa Barbara area along Casitas Pass Road. As it neared the lake approaching from the W, it made a horseshoe turn and proceeded to cross the lake along a route that is now underwater, veering N to meet Baldwin Road near the SB Santa Ana Road connection. Sign Route 150 then followed Baldwin Road (and Old Baldwin Road) to meet Ventura Avenue. But the USGS maps also show other routes signed as part of Sign Route 150: Notably, a connection (again, now underwater) to Casitas Vista Road (likely a continuation of Casitas Pass Road) that continued to meet Ventura Road, where it continued S into Ventura as a US 399/Sign Route 150 cosign. The pre-lake Sign Route 150 met another road that is now also underwater, continuing to the NE to about where Santa Ana Road is, where it met today's Route 150 at Baldwin Road. That same USGS map also shows Sign Route 150 running from the Ventura Road/Santa Ana Road junction along Santa Ana Road and Burnham Road to Baldwin Road. The USGS maps are notorious for sometimes showing roads as signed that weren't, but as it was the ACSC that was doing the signing and numbers were less significant to folks, there were often spurs or alternates signed with the number. However, it is clear that Sign Route 150 shared US 399 between Baldwin Road and Ojai Avenue, split back off on its lonesome to the E along Ojai Avenue as solely Sign Route 150.

After the Ojai Freeway was constructed in the early 1950s, the routing in Ventura changed. By 1956, US 399 was using a connector that started near N. Thompson and Main (US 101) near N Garden, which went diagonally to pick up the Ojai Freeway near Park Row Avenue (Note that S. Garden was the US 101 connector between Thompson and W Main before the freeway). That connector was modified with the construction of the Mission Plaza Shopping Center; it now starts off of N Olive below Rex Street, providing accessibility to the Ojai Freeway (now Route 33, nee US 399) from W. Main (which was US 101). After the freeway portion of the Ojai Freeway ends heading N (see the page on Route 33), the road downgrades into Ventura Avenue.

In December 1956, US 399 was moved to the first part of the new Ojai Freeway to open, out of Ventura to the first Ventura Ave overpass. The freeway started at the Main St/S. Garden (now BR 101) and headed NW past Olive Street and past what are now the ramps for the Main St exit.
(Source: Mapmikey: The Virginia Highways Project: US Highways: Histories for Mainline, Suffixed, and Bannered Routes: US␠399)

Between Baldwin Avenue and Ojai Avenue, US 399 was co-signed with Sign Route 150. Sign Route 150 split off at Ojai Ave, and US 399 continued along Maricopa Avenue which turned into Maricopa Highway, now Route 33.

Near Ojala (near Matilijia Lake), around 1949, US 399 was removed from the lower part of the Ojala Quarry driveway; and around 1953, US 399 was removed from the driveway to 15275 Hwy 33 south of Ojala, which no longer connects back up with Route 33.
(Source: Mapmikey: The Virginia Highways Project: US Highways: Histories for Mainline, Suffixed, and Bannered Routes: US␠399)

Maricopa Highway continued as US 399 (today's Route 33) to a point E of Cuyama Ranch, where it met Sign Route 166 and continued co-signed to the NE (this is today a Route 33/Route 166 cosign, legislatively Route 33) into Maricopa. In Maricopa, Sign Route 166 continued to the E along Maricopa Highway, while US 399 continued (potentially cosigned with Sign Route 33) N along California St. This later became today's West Side Highway; it is unclear the former name of the road.

In the period between 1934 and 1938 between the outskirts of Maricopa and Taft, US 399 originally used Petroleum Club Road. This corridor was constructed as a frontage road of the Sunset Railroad and would be the site of the Lakeview Gusher in 1910. In January 1938, US 399 was moved to the current West Side Highway routing. Within Taft, before 1935, US 399 used Wood St. to abandoned route north that is now a parking lot adjacent to West Kern Oil Museum, to today's Taft Bypass, to Center St. or Main St, to 1st St to Kern St.to 6th St/Harrison St. In May 1935, US 399 was given a more direct routing through Taft using West Side Hwy, Kern St, and 6th St/Harrison St.
(Source: Mapmikey: The Virginia Highways Project: US Highways: Histories for Mainline, Suffixed, and Bannered Routes: US␠399; Gribblenation Blog, "Petroleum Club Road (former California State Route␠33 and US Route␠399 past the Lakeview Gusher)", 5/6/2026)

Within Taft, US 399 originally ran along 6th Street/Harrison Street, with Sign Route 33 splitting off at San Emigdio Street. Later, the route was adjusted to have Sign Route 33 continue on Kern Street. This happened in 1935, when Sign Route 33 (LRN 138) was realigned through Taft. The then new alignment was constructed onto two extensions of Kern Street on both sides of downtown. The multiplex of US 399 and Sign Route 33 was realigned to meet at Kern Street and 6th Street.
(Source: Gribblenation Blog, "Petroleum Club Road (former California State Route␠33 and US Route␠399 past the Lakeview Gusher)", 5/6/2026)

Proposed Rerouting of U.S. 399 in TaftIn 1952, a freeway alignment was adopted for US 399 (now Route 33 and Route 119) through Taft. The plan was to widen US 399 through Taft to a point 1.3mi N of the town's city limits. Project plans were under study The bypass was constructed in 1956. Subsequent discussion on the Facebook post where this map was posted indicated that the final adopted routing differed slightly from the routing shown. Specifically, the proposed route seems to show the new routing running along Monroe St, whereas the actually routing runs about 6-7 blocks to the E, running straight to the N and curving back after passing what is shown as the US Navy land in the diagram. In any case, by 1956, US 399 was using the alignment used by today's Route 119: veering off the West Side Highway/Kern Street at Taft Highway. It merges with the old allignment, Harrison St. just N of the town of Taft in a community called Ford City. Note that Harrison Street continues NE after the first merge to meet Taft Highway again, at a point E of Elk Hills Road; that portion of Harrison Street was the original US 399 prior to the Taft Highway realignment.
(Source: Art Moore on FB, 12/22/2022, sharing map from the Bakersfield Californian, 12/23/1952)

US 399 continued E along Taft Highway. Near the N Coles Oil Field, US 399 originally veered off along today's Golf Course Road and Tupman Road (now Golf Course Road, until it crosses Taft Highway and becomes Tupman again). That loop was cutoff by the construction of Taft Highway. US 399 continued along Taft Highway into Greenfield, where it met US 99.

The original route of US 99 used Union/19th/Chester through downtown Bakersfield. In June 1934, US 99 was rerouted in Bakersfield to use Union to Golden State Ave. It is unclear if US 399 even entered Bakersfield solely as US 399. If it did, it would have run from Taft Highway to where it meets Stine Road (Taft Highway may have been Panama Road at this time). It then would have run a connection with Wilson Road, then E to Wible Road, N to Bell Terrace, E to Oleander Ave, N on Oleander to Brundage Lane, E on Brundage to Chester, and then N on Chester to 19th/Chester, where it would have ended with US 466. As US 99 was later removed from downtown, the timing of that removal would have been when US 399 was changed to follow Taft Hwy to US 99 in Greenfield, then north co-signed with US 99 to likely end at US 466 (Golden State Ave at Sumner St). However, it is extremely unlikely US 399 was posted on the solo approach, if it went that way at all.
(Source: Mapmikey: The Virginia Highways Project: US Highways: Histories for Mainline, Suffixed, and Bannered Routes: US␠399)

The 1936-37 Division of Highways Map shows US 399 (defined in 1934) co-signed with US 99 on Golden State Avenue. US 399 is shown to multiplex US 99 from Greenfield into downtown Bakersfield via Union Avenue where it would have terminated at US 466. In 1957, US 99/US 466/LRN 4 on Golden State Avenue was relocated to an overpass of the Garces Traffic Circle. Connection to LRN 142/Chester Avenue would be made from the US 99/US 466/LRN 4 overpass via frontage roads. The first units of the Bakersfield Bypass freeway routing were funded in 1960-1961, and opened in 1962. US 99 moved to the "West Bakersfield" freeway in 1963. The West Bakersfield Freeway saw the relinquishment of Union Avenue south of Brundage Lane/LRN 141, which truncated US 399 out of Bakersfield to US 99 at Pumpkin Center on Taft Highway.
(Source: Gribblenation Blog (Tom Fearer), "California State Route␠204; former US Route␠99, US Route␠399 and US Route␠466 in Bakersfield", April 2021)
In 1962, the portion of US 399 in Bakersfield was later relegated to Business Loop status in 1962, and became BR 99/Route 204 in 1964. However, the portion of former US 399 south of Brundage Lane (current parallel street to Route 58, the replacement for US 466) was removed from the state route in 1978; only the portion of former US 99 on Union Avenue from Golden State Avenue/Sumner Street south to Route 58 remains in the state system as Route 204. All of the route remains part of BR 99.

On May 1, 1963, the Division of Highways submitted a request to the AASHO Executive Committee to remove US 399 as part of the planned 1964 California State Highway Renumbering. This request was considered by the AASHO Executive Committee on June 19th, 1963 and met with their approval. US 399 subsequently would effectively cease to exist as of 1/1/1964. US 399 was replaced by Route 119 from Bakersfield to Taft and by a realigned Route 33 from Maricopa via the Ventura-Maricopa Highway to Ventura (including a co-signed portion with Route 166).
(Source: Gribblenation Blog (Tom Fearer), "California State Route␠33 and legacy of US Route␠399 on the Maricopa-Ventura Highway", August 2021)

With the decommissioning of US 399, Ventura to Taft became Route 33 (and is still Route 33 today except that the diagonal arterial between Main St/S Garden St in Ventura was torn out, leaving only the ramps to/from Olive St to Ojai Freeway). There is also supposedly an abandoned diagonal in Maricopa between Alameda St and the Route 33/Route 166. Additionally, with the decomissioning, Taft to Greenfield became Route 119 (although, as noted above, there was a rerouting off Golf Course Rd north of Dustin Acres).
(Source: Mapmikey: The Virginia Highways Project: US Highways: Histories for Mainline, Suffixed, and Bannered Routes: US␠399)

[NE2]

The 1924 state map shows LR 57 on a zigzag route into Bakersfield, partly marked "paved by local authorities - not taken over by state". But by 1926 it was planned straight east from Maricopa. Based on the railroad, the local-built part in 1924 appears to be Old River Road, Panama Lane, Stine Road, Wilson Road (?), and Wible Road.