Louisiana Highway 3150 (LA 3150) runs 0.29 miles (0.47 km) in a north–south direction along Minnich Lane from LA 1 to a point near Louisiana Avenue, a local road, in Grand Isle, Jefferson Parish. It is an undivided two-lane highway for its entire length.
The route was designated as LA 574-10 prior to 1972, when five digit routes were eliminated by the state highway department.
Louisiana Highway 3151 (LA 3151) runs 1.12 miles (1.80 km) in a general north–south direction along Humble Road, looping off of LA 1 in Grand Isle, Jefferson Parish. It is an undivided two-lane highway for its entire length.
The route was designated as LA 574-11 prior to 1972, when five digit routes were eliminated by the state highway department.
The route initially heads north on Hickory Avenue, an undivided two-lane thoroughfare, from LA 48 (Jefferson Highway) in Harahan. At Roberts Street, signs direct traffic onto Dickory Avenue, a parallel divided four-lane thoroughfare, to continue north on LA 3154. Officially, the route leaves Hickory Avenue further north via Gardner Street (also the connector for southbound traffic), requiring a U-turn before proceeding north on Dickory Avenue. Now outside the Harahan city limits, LA 3154 intersects LA 3139 (Earhart Expressway) and proceeds across the Canadian National Railway (CN) tracks via an overpass into Metairie. The highway proceeds a short distance further to its terminus at US 61 (Airline Drive).
LA 3154 was designated as LA 574-11 prior to 1972, when five digit routes were eliminated by the state highway department. The route originally followed Hickory Avenue for its entire length and crossed what was then the Illinois Central Railroad (IC) line at grade. Construction began in 1974 on a four-lane bypass of Hickory Avenue that would include a railroad overpass and an interchange with the future Earhart Expressway. The new alignment, Dickory Avenue, opened in December 1975 and extended from Citrus Road to Airline Highway (now Airline Drive). Almost two decades later, Dickory Avenue was extended slightly to the south, providing better access to the Elmwood Business Park. In 2003, a further extension continued the road to its present terminus just south of 9th Street, providing another route into the Elmwood Business Park via an extension of Mounes Street. Plans are underway to extend the road to Jefferson Highway and bypass the remainder of Hickory Avenue.
The route connects Hahnville, the parish seat, with LA 3127, a highway constructed in the 1970s that bypasses the various communities along the west bank of the Mississippi River between Luling and Donaldsonville. It is an undivided two-lane highway for its entire length.
Louisiana Highway 3161 (LA 3161) runs 0.73 miles (1.17 km) in an east–west direction from LA 3235 to LA 1 in Cut Off, Lafourche Parish. The route is a short connector between LA 1 and its four-lane bypass, LA 3235. It is also signed as the Cote Blanche Connection and is an undivided two-lane highway for its entire length.
Louisiana Highway 3162 (LA 3162) runs 0.70 miles (1.13 km) in an east–west direction from LA 3235 to LA 308 in Galliano, Lafourche Parish. The route is a short connector between LA 1 and its four-lane bypass, LA 3235. It extends east across Bayou Lafourche by way of a vertical lift bridge, connecting LA 1 and LA 308, which travel along opposite banks of the bayou. LA 3162 is an undivided two-lane highway for its entire length.
Louisiana Highway 3168 (LA 3168) runs 0.67 miles (1.08 km) in a north–south direction from US 90 to a point just south of I-10 in Scott, Lafayette Parish. The route is entirely co-signed with LA 93.
LA 3168 heads north from US 90 along Apollo Road. Upon reaching a roundabout intersection with St. Mary Street, the town's main north–south thoroughfare, the LA 3168 designation ends. LA 93 continues immediately through an interchange with I-10 at Exit 97.
LA 3168 was constructed around 1979 as a truck route for LA 93, which followed St. Mary Street through the center of town. It became the actual route of LA 93 when St. Mary Street was subsequently returned to local control. However, the LA 3168 designation remains and is entirely co-signed with the portion of LA 93 on Apollo Road.
The route begins at LA 105 (South Levee Road) and proceeds west along 2nd Street. It then turns north onto 9th Avenue, crosses the Union Pacific Railroad (UP) tracks, and intersects LA 3174 (Main Street). LA 3173 turns east onto Main Street for one block then north onto 8th Avenue to an intersection with LA 3178 (Florida Street). Here, LA 3173 turns west and reaches its terminus at US 190 just west of the Krotz Springs Bridge over the Atchafalaya River. LA 3173 is an undivided two-lane highway for its entire length.
The upper section of LA 3173 was formerly part of LA 105 before the construction of the current westbound bridge span caused a slight realignment of that route. LA 3173 was added to the state highway system around 1973, and its route has remained the same to the present day.
The route begins at US 190 and heads south briefly before curving to the east. It enters the town of Krotz Springs and proceeds to a terminus at LA 3173 (9th Avenue). LA 3174 is an undivided two-lane highway for its entire length. Truck traffic from the industrial area south of town is directed onto LA 3174 to reach westbound US 190.
The route begins at the intersection of Florida Street and 8th Avenue, a junction with LA 3173, and proceeds east to LA 105 (North Levee Road). It provides a more direct connection between US 190 and LA 105 at the west end of the Krotz Springs Bridge over the Atchafalaya River. It is an undivided two-lane highway for its entire length.
LA 3178 connects the original and current alignments of LA 105, which was slightly realigned in the early 1970s when the current westbound span of the Krotz Springs Bridge was constructed.
The route heads northwest on Bertrand Drive from LA 3025 then curves due north onto Ambassador Caffery Parkway. Shortly afterward, LA 3184 intersects US 90 (Cameron Street). The highway then crosses the BNSF/Union Pacific Railroad (UP) tracks by way of an overpass and proceeds to an interchange with I-10 at Exit 100. LA 3184 is a divided four-lane highway for its entire length.
LA 3185 initially heads southwest from LA 308 (Bayou Road), immediately crossing Bayou Lafourche and intersecting LA 1. The route continues through an area known as Leighton and intersects Louisiana Highway 3107 (Talbot Avenue). After curving to the southeast, LA 3185 crosses from Lafourche Parish into Terrebonne Parish. The highway terminates soon afterward at LA 20 in Schriever. It is an undivided two-lane highway for its entire length.
LA 3188 heads north from US 61 (West Airline Highway) on Belle Terre Boulevard, a divided four-lane commercial thoroughfare. There are four signalized intersections along the route: US 61, a shopping strip entrance, Fairway Drive, and St. Andrews Boulevard. Just north of the latter, LA 3188 enters an undeveloped area at the north end of LaPlace. The highway curves to the northeast, engaging in a trumpet interchange with I-10 at Exit 206, connecting to New Orleans and Baton Rouge.
The highway was constructed in the early 1980s and involved re-routing and extending the existing Belle Terre Boulevard to I-10. The original alignment curved northeast onto what is now Lakewood Drive, ending at the Belle Terre Country Club.
From the south, LA 3193 begins at LA 44, which follows the east bank levee of the Mississippi River. It proceeds northwest on Lutcher Avenue, an undivided two-lane residential thoroughfare. Just after crossing the Canadian National Railway (CN) tracks at grade, the highway intersects LA 641 (West Main Street). LA 3193 continues past St. James Parish Hospital and widens to a divided four-lane highway shortly before reaching its terminus at LA 3125.
Louisiana Highway 3197 (LA 3197) runs 0.49 miles (0.79 km) in a southwest to northeast direction along Bayou Black Drive between two points on LA 182 in Houma, Terrebonne Parish. It is a discontinuous remnant of the original alignment of US 90 through the area.
From the southwest, LA 3197 begins at a junction with LA 182 and LA 315 at the intersection of Bayou Black Drive and Barrow Street. It proceeds northeast on Bayou Black Drive alongside the Houma Golf Course. At the intersection of Bayou Black Drive with Country Club Drive and Mulberry Road, LA 3197 turns northwest and shortly reaches a dead end at the former location of the Houma Canal bridge. The route resumes on the north side of the canal and proceeds northwest a short distance to its terminus at LA 182 (Barrow Street) opposite the concurrent LA 311 and LA 312.
LA 3197 is an undivided two-lane highway for its entire length.
Louisiana Highway 3198 (LA 3198) ran 3.3 miles (5.3 km) in a southwest to northeast direction along what is now LA 182 connecting Raceland with US 90 in Lafourche Parish. LA 3198 was part of the original alignment of US 90 before the Raceland bypass was opened in the late 1970s.
From the southwest, LA 3198 began at an interchange with US 90 (Exit 210) and LA 3052 (now also part of US 90). It proceeded northeast along the present LA 182, intersecting LA 653 and LA 652 on the way to Raceland. LA 3198 reached its terminus at LA 1 in Raceland opposite Bayou Lafourche.
Louisiana Highway 3199 (LA 3199) ran 3.6 miles (5.8 km) in a southwest to northeast direction along what is now LA 182 connecting Raceland with US 90 in Lafourche Parish. LA 3198 was part of the original alignment of US 90 before the Raceland bypass was opened in the late 1970s.
From the southwest, LA 3199 began at an intersection with LA 1 on the south side (west bank) of Bayou Lafourche. It proceeded northeast along the present LA 182, intersecting LA 307 along the northeastern tip of Raceland. LA 3199 reached its terminus shortly thereafter at US 90 alongside the BNSF/Union Pacific Railroad (UP) tracks.