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Interstate 12
Interstate 12
Interstate 12
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Interstate 12 marker
Interstate 12
Republic of West Florida Parkway
Map
I-12 highlighted in red
Route information
Maintained by Louisiana DOTD
Length85.59 mi[1] (137.74 km)
Existed1967–present
NHSEntire route
Major junctions
West end I-10 in Baton Rouge
Major intersections
East end I-10 / I-59 in Slidell
Location
CountryUnited States
StateLouisiana
ParishesEast Baton Rouge, Livingston, Tangipahoa, St. Tammany
Highway system
  • Louisiana State Highway System
← US 11→ LA 12

Interstate 12 (I-12) is an intrastate Interstate Highway located entirely within the US state of Louisiana. It spans a total of 85.59 miles (137.74 km)[1] in an east–west direction from I-10 in Baton Rouge to an interchange with both I-10 and I-59 in Slidell. Along the way, it passes through the city of Hammond, where it intersects I-55 and US Route 51 (US 51). It also serves the cities of Ponchatoula and Denham Springs, as well as the St. Tammany Parish cities of Covington and Mandeville.

I-12 parallels the older US 190 corridor and traverses the north shore of Lake Pontchartrain in the southeastern portion of the state. The Interstate's length is short for a mainline Interstate and is comparable with the country's longest auxiliary Interstates. It is one of the shortest mainline Interstates to terminate at the same route (I-10) at either end. Apart from serving the various communities of the North Shore, I-12 acts as a long bypass of New Orleans and is heavily used as a shortcut for through traffic on I-10. While I-10 curves to the south to pass through the city limits, I-12 takes a more direct alignment, reducing the distance between Baton Rouge and Slidell by about 22 miles (35 km).

In 1993, the Louisiana State Legislature designated I-12 as the Republic of West Florida Parkway. In 2003, signs identifying the highway's official name and bearing the flag of the Republic of West Florida were erected by the Louisiana Department of Transportation and Development (DOTD) in order to highlight the unique history of Louisiana's Florida Parishes.

Louisiana is in the process of widening I-12 to three lanes in each direction in locations such as Covington and Mandeville where the Interstate is still two lanes in each direction.

Route description

[edit]
Western terminus in Baton Rouge
I-12's eastbound exit to LA 1249, which leads to the communities of Baptist and Pumpkin Center
At the bottom of I-12's eastbound ramp to LA 59, travelers also find a shield for the unrelated I-59, some 20 miles (32 km) farther east

Baton Rouge to Hammond

[edit]

From the west, I-12 begins three miles (4.8 km) east of downtown Baton Rouge in East Baton Rouge Parish at an interchange with I-10 known as the I-10/I-12 split. While I-10 heads to the southeast toward the New Orleans metropolitan area, I-12 proceeds eastward toward the North Shore of Lake Pontchartrain. Before leaving Baton Rouge, I-12 intersects some of its major arteries, including Louisiana Highway 3064 (LA 3064; Essen Lane) and LA 73 (Jefferson Highway) via LA 1068 (Drusilla Lane). It then passes through a cloverleaf interchange with US 61 (Airline Highway). These three exits serve several of the area's key medical and shopping centers, such as the Our Lady of the Lake Regional Medical Center and Cortana Mall. The final exit in Baton Rouge is an interchange with LA 3245 (O'Neal Lane), which serves the Ochsner Medical Center-Baton Rouge and eastern suburbs.[2][3][4]

I-12 reaches the Amite River 1.3 miles (2.1 km) later, where it enters Livingston Parish and the city of Denham Springs. I-12 skirts the southern edge of town, providing interchanges with LA 3002 (South Range Avenue) and LA 1026 (Juban Road). East of Denham springs, I-12 skirts the southern edge of Livingston Parish's only other city, Walker. The interstate's sole exit in Walker is exit 15, an interchange with LA 447.

Past Walker are smaller communities in the eastern half of the parish. Exits include: LA 63 serving Livingston (exit 22), LA 441 serving Holden (exit 29), and LA 43 serving Albany and Springfield (exit 32).[2][5][6]

Shortly after crossing the Natalbany River into Tangipahoa Parish, I-12 intersects LA 1249, which leads to the communities of Baptist and Pumpkin Center. I-12 enters into a cloverleaf interchange 3.2 miles (5.1 km) later with I-55 at the southeast corner of Hammond, the largest city in Tangipahoa Parish. I-55 heads toward Jackson, Mississippi, on the north and New Orleans on the south. A mile (1.6 km) after, US 51 crosses I-12, but the two roads do not intersect. There is instead an interchange with US 51 Business, which serves downtown Hammond, as well as the city of Ponchatoula to the south.[2][6][7]

Hammond to Slidell

[edit]

East of Hammond are two rural exits in southeastern Tangipahoa Parish: LA 3158 (Airport Road) to Hammond Northshore Regional Airport and LA 445 to Robert.

Just after crossing into St. Tammany Parish, I-12 curves to the southeast and begins to parallel the North Shore of Lake Pontchartrain. An interchange with LA 1077 serves the town of Madisonville to the south. The following exit, an interchange with LA 21, also connects to Madisonville as well as the parish seat of Covington to the north. Immediately before crossing the Tchefuncte River, an exit to Pinnacle Parkway and East Brewster Road serves the growing shopping area east of LA 21.

Two miles (3.2 km) east of the bridge, I-12 passes through an interchange with US 190 between Covington and Mandeville. This section of US 190 serves as St. Tammany Parish's busiest north–south thoroughfare, connecting Covington and surrounding points with the Lake Pontchartrain Causeway, a 24-mile-long (39 km) bridge leading to New Orleans. Further exits in St. Tammany Parish west of Slidell include LA 59 to Mandeville and Abita Springs, LA 1088 to LA 36, and LA 434 to Lacombe.[2][6][8]

I-12 passes through an interchange with Airport Drive 6.3 miles (10.1 km) east of the Lacombe exit, which connects to Slidell Airport due north. At this exit, I-12 enters the northern edge of Slidell. An interchange with US 11 connects to the downtown area. Less than two miles (3.2 km) later, I-12 reaches its eastern terminus at a major interchange with I-10 and I-59 at the northeast corner of town. From this interchange, I-10 heads southwest toward New Orleans and east toward Bay St. Louis, Mississippi, while I-59 heads north toward Hattiesburg, Mississippi.[2][6][9]

History

[edit]

I-12 was added to the highway system on October 17, 1957, with I-12 running from I-10 in Baton Rouge to I-59 north of Slidell.[10] By the mid-1960s, the routes had been realigned to their current configuration, with I-12 and I-59 both ending at I-10 near Slidell.[11] The route was opened to traffic in several sections between January 1967 and June 1976.[12][13]

With major damage to the I-10 Twin Span Bridge across Lake Pontchartrain from Hurricane Katrina, I-12 was temporarily functioning as I-10 between Baton Rouge and Slidell. On October 14, 2005, the eastbound span of I-10 over Lake Pontchartrain reopened to two-way traffic. The westbound span of I-10 reopened on January 6, 2006, with speed, weight and size restrictions, relieving I-12 of much of the congestion that was clogging it from the Lake Pontchartrain Causeway to the junction with I-10 and I-59.

Since 2012, the DOTD has been widening the Interstate from four lanes to six lanes to accommodate the increasing amount of traffic and make the section safer.[14][15][16][17][18] The I-10/I-12/I-59 split, notorious for rough pavement, was repaved in 2015.[citation needed]

Exit list

[edit]
ParishLocationmi[19]kmExitDestinationsNotes
East Baton RougeBaton Rouge0.000–
0.903		0.000–
1.453		1A I-10 – Baton Rouge, New OrleansWestern terminus; signed as exit 1A to I-10 east only; exit 159 on I-10
1.223–
1.649		1.968–
2.654		1B LA 3064 (Essen Lane)No westbound exit
2.204–
2.275		3.547–
3.661		1C
 LA 1068 (Drusilla Lane) to LA 73 (Jefferson Highway)		Eastbound entrance and westbound exit
2.608–
3.206		4.197–
5.160		2 US 61 (Airline Highway)Signed as exits 2A (south) and 2B (north); to Hammond Aire Plaza and Mall at Cortana
3.807–
4.447		6.127–
7.157		4Sherwood Forest Boulevard
5.707–
6.498		9.185–
10.458		6Millerville Road
6.844–
7.454		11.014–
11.996		7O'Neal LaneFormer LA 3245
East Baton Rouge–Livingston
parish line		Denham Springs8.410–
8.902		13.535–
14.326		Bridge over Amite River
Livingston10.040–
10.599		16.158–
17.057		10 LA 3002 – Denham Springs
​12.442–
13.033		20.023–
20.975		12 LA 1026 (Juban Road)
Walker15.711–
16.338		25.284–
26.293		15 LA 447 – Walker, Port Vincent
​19.604–
20.359		31.550–
32.765		19 PR 45 – Satsuma, Colyell
Livingston22.602–
23.468		36.374–
37.768		22 LA 63 – Livingston, Frost
​28.667–
29.745		46.135–
47.870		29 LA 441 – Holden
​32.504–
33.334		52.310–
53.646		32 LA 43 – Albany, SpringfieldTo Tickfaw State Park
Tangipahoa​34.848–
35.562		56.082–
57.231		35 LA 1249 – Baptist, Pumpkin Center
Hammond38.015–
38.735		61.179–
62.338		38 I-55 – New Orleans, JacksonSigned as exits 38A (south) and 38B (north); exit 29 on I-55
40.016–
40.595		64.400–
65.331		40
 US 51 Bus. – Hammond, Ponchatoula
​42.378–
43.156		68.201–
69.453		42
 LA 3158 north (Airport Road)		Southern terminus of LA 3158; to Chappapeela Sports Park and Hammond Northshore Regional Airport
​47.418–
48.184		76.312–
77.545		47 LA 445 – Robert
St. Tammany​56.702–
57.855		91.253–
93.109		57 LA 1077 – Goodbee, MadisonvilleTo Fairview Riverside State Park
​59.101–
60.138		95.114–
96.783		59 LA 21 – Covington, Madisonville
​60.220–
60.958		96.915–
98.102		60Pinnacle Parkway / East Brewster Road
​60.953–
61.240		98.094–
98.556		Bridge over Tchefuncte River
​62.580–
63.565		100.713–
102.298		63 US 190 – Covington, MandevilleSigned as exits 63A (east) and 63B (west); additional destinations are New Orleans via Lake Pontchartrain Causeway and Bogalusa
​65.710–
66.387		105.750–
106.840		65 LA 59 – Abita Springs, Mandeville
​68.195–
69.101		109.749–
111.207		68
 LA 1088 to LA 36 – Mandeville
Lacombe73.995–
74.773		119.083–
120.335		74 LA 434 – Lacombe, St. Tammanyto future LA 3241
Slidell80.160–
81.149		129.005–
130.597		80Airport Drive / North Shore BoulevardTo Slidell Municipal Airport and Camp Villere / Southeast Louisiana Veterans Cemetery
83.620–
84.152		134.573–
135.430		83 US 11 – Slidell, Pearl River
85.375–
86.653		137.398–
139.454		85 I-10 / I-59 – New Orleans, Biloxi, HattiesburgEastern terminus of I-12; southern terminus of I-59; signed as exits 85A (I-10 west), 85B (I-59) and 85C (I-10 east); exit 267B on I-10; exit 1C on I-59
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

See also

[edit]

References

[edit]
[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Interstate 12

View on Grokipedia
from Grokipedia
Interstate 12 (I-12) is an auxiliary Interstate Highway located entirely within the U.S. state of . It measures 86.65 miles (139.45 km) in length and extends from an interchange with (I-10) west of Baton Rouge to a junction with I-10 and (I-59) in Slidell. The route begins at its western terminus near Baton Rouge, where it connects to I-10, and proceeds eastward through East Baton Rouge, Livingston, Tangipahoa, and St. Tammany parishes before reaching Slidell. Along the way, I-12 provides direct access to key communities on the north shore of , including Denham Springs, Walker, Hammond, Covington, and Lacombe. As part of the National Highway System, it functions as a vital for transcontinental on I-10, avoiding the congested urban core of New Orleans to the south. Designated as a mainline Interstate route, I-12 supports regional mobility and economic connectivity in southeastern . Recent widening projects, including the completion of a major expansion in St. Tammany Parish in November 2025, have enhanced capacity in high-traffic segments. The highway is maintained by the and carries significant daily volumes, contributing to the state's overall interstate network of over 890 miles.

Route description

Western segment (Baton Rouge to Hammond)

Interstate 12 begins at its western terminus with in East Baton Rouge Parish, approximately three miles east of downtown Baton Rouge, where it serves as a northern bypass for traffic seeking to avoid congestion in the urban core of the capital city. The highway heads eastward through suburban landscapes, initially configured with six lanes between the O'Neal Lane interchange (Exit 7, LA 3245) and the Walker exit (Exit 15, LA 447), accommodating higher volumes near the . Entering Livingston Parish shortly after the Walker interchange, I-12 narrows to four lanes—two in each direction—and traverses rural terrain dominated by pine forests and extensive wetlands associated with the Amite River basin. Notable interchanges along this stretch include Louisiana Highway 3002 (Exit 10) and Louisiana Highway 1026 (Exit 12) in Denham Springs, providing access to local commercial districts, and Louisiana Highway 447 (Exit 15) near Walker and Port Vincent, connecting to residential and agricultural communities. The route features a bridge crossing over the Amite River amid surrounding low-lying, flood-prone geography. Further east in Livingston Parish, I-12 intersects (Exit 32) near Albany, a critical junction linking the east-west corridor to north-south travel routes extending toward . As of 2010, average daily traffic volumes in this rural expanse ranged from 39,000 to 71,000 vehicles, supporting commuter flows from Livingston Parish communities to Baton Rouge employment centers without delving into urban density. Crossing into Tangipahoa Parish, the highway maintains its four-lane profile while the surroundings gradually transition to more developed suburban environments approaching Hammond. Key access points include Louisiana Highway 43 (Exit 32) serving Albany and Springfield to the north, and U.S. Highway 190 (Exit 35) near Natalbany, facilitating entry into Hammond's commercial and educational hubs, including . This segment underscores I-12's role in regional mobility, with its I-55 connection enabling efficient north-south integration and contributing to the overall function as a bypass for New Orleans-area travel.

Eastern segment (Hammond to Slidell)

From its interchange with I-55 in Hammond, Interstate 12 (I-12) continues eastward through southeastern Tangipahoa Parish and into St. Tammany Parish, serving as a key northshore corridor parallel to the southern shore of . The highway initially traverses rural, forested landscapes dominated by pine woodlands, providing access to smaller communities via exits such as LA 445 near (Exit 47) and LA 1077 near Goodbee (Exit 57). Further east, I-12 features an interchange with LA 21 near Covington (Exit 59), while the route remains in close proximity to the lake's northern edge, with occasional glimpses of the water through the tree line. Near Lacombe, an interchange with LA 434 (Exit 74) provides access to local communities. As I-12 progresses toward Covington and Mandeville, the terrain shifts to a mix of suburban expansion and commercial development, reflecting rapid growth in the Northshore region driven by residential and retail influx. Key interchanges include US 190 near Covington (Exits 63A/B), which links to the Lake Pontchartrain Causeway, and LA 59 south to Mandeville (Exit 65), where the highway offers elevated views of the lake and supports local economic hubs like shopping centers and office parks. The route crosses the via a bridge near Mandeville, a designated scenic that highlights the area's natural beauty amid increasing . Approaching Slidell, I-12 passes through more developed northern suburbs, with exits providing access to local businesses and residential areas before terminating at a major with I-10 and I-59 (Exit 85, corresponding to I-10 Exit 261). This eastern terminus facilitates seamless connections eastward to the via I-10, underscoring I-12's role as a bypass avoiding New Orleans congestion. As of 2025, the highway generally maintains four lanes, with six-lane sections in busier areas including between Exits 57 (LA 1077) and 59 (LA 21) following recent widening completion, and experiences high traffic volumes of 80,000 to over 120,000 vehicles daily, particularly in the Covington-Mandeville corridor, due to , commuting, and hurricane evacuation routes. Environmentally, the eastern segment of I-12 navigates sensitive coastal ecosystems, including crossings over the and adjacency to freshwater forested and shrub wetlands associated with the Tchefuncte and basins in St. Tammany Parish, which support diverse wildlife and mitigate flooding but face pressures from regional development. Near Slidell, the route skirts the Wildlife Management Area, preserving habitats amid the highway's path through bottomland hardwoods and marshes.

History

Planning and designation

The planning for Interstate 12 originated as part of the national , with the route formally designated on October 17, 1957, to connect I-10 near Baton Rouge to I-59 north of . This designation aligned with the , which authorized the development of a nationwide network of high-mobility highways to support defense, commerce, and civilian travel, though specific alignments like I-12 were refined in subsequent federal approvals during the late 1950s. The Louisiana Department of Highways, the state's primary transportation authority at the time, collaborated with the Bureau of Public Roads to integrate the route into broader system goals, emphasizing its role in enhancing connectivity across southeastern . The primary conceptualization of I-12 focused on its function as a bypass for I-10 around New Orleans, addressing anticipated congestion in the urban core and providing a more direct east-west corridor north of . Early feasibility considerations in the late 1950s highlighted economic advantages, including improved freight movement between Baton Rouge and the Gulf Coast ports while avoiding the bottlenecks of New Orleans, and enhanced evacuation routes for hurricanes affecting the Northshore region. State planners prioritized alignments that minimized disruption to populated areas, drawing on preliminary studies to ensure the highway supported regional growth without exacerbating . In 1993, the officially named the highway the Parkway, commemorating the short-lived 's 1810 secession from Spanish rule in the region through which I-12 passes. This designation included provisions for commemorative signage featuring the republic's flag emblem—a single white on a blue background—to highlight the area's unique historical identity. In 2003, signs identifying the highway's official name and bearing the flag of the were erected along the route. The naming reflected ongoing state efforts to tie to local heritage, distinct from the federal numbering system established decades earlier.

Construction and opening

Construction of Interstate 12 began in 1966 on the western segment near Baton Rouge, with the first section opening to traffic in January 1967 from I-10 to LA 30. This initial phase provided an early bypass for local traffic around the , marking the start of the highway's development as an alternative to the more congested I-10 corridor. The project was funded primarily through the federal Interstate Highway program, which covered 90 percent of costs, with the state of contributing the remaining 10 percent, involving multiple contractors for grading, paving, and bridge work. The western segment progressed in phases, reaching full completion from Baton Rouge to Hammond by 1969, including the connection to I-55. Engineering challenges included constructing bridges over rivers such as the Amite and Tchefuncte, as well as navigating extensive wetlands typical of Louisiana's , requiring specialized drainage and foundation techniques to ensure stability. The opening of the Hammond segment was marked by a dedication highlighting its role in regional connectivity, and early traffic data showed immediate relief for commuters avoiding downtown areas. By 1976, the eastern extension from Hammond to I-59 near Slidell was complete, with the final link to I-10 opening that June, fully realizing the 86-mile route. Post-opening, I-12 quickly became a vital evacuation and commercial artery, though initial two-lane capacity led to calls for expansions in subsequent decades.

Expansions and future plans

Widening projects

In the and , several widening initiatives on Interstate 12 added paved shoulders and auxiliary lanes in areas near Hammond and Covington to accommodate increasing suburban traffic growth along the Northshore corridor. Major expansion efforts in the and focused on adding lanes in high-congestion zones, including the $169.8 million project to widen approximately 10 miles of I-12 from LA 59 in Mandeville to LA 1077 in Covington, completed in phases between 2018 and 2025. This initiative involved median widening to accommodate six lanes, asphalt overlays on existing pavement, and expansions of multiple bridges, including structures over local waterways such as Ponchatoula Creek, to improve capacity and safety. Key completions in 2025 included the $57 million widening of 3.5 miles from LA 1077 to LA 21 in St. Tammany Parish, with expanded lanes opened on October 16, 2025, and officially completed on November 13, 2025, which added travel lanes and reduced congestion in the Covington area through inside widening and new pavement. This marked the completion of the six-lane expansion across the greater Mandeville/Covington area from LA 59 to LA 1077. Repairs following in 2005, which damaged sections of I-12 near Slidell, informed subsequent widening designs by emphasizing resilience features, such as elevated roadway segments and improved drainage in flood-prone areas. By 2025, cumulative investments in I-12 widening projects exceeded $300 million, with a primary emphasis on high-traffic hotspots in St. Tammany Parish, including Mandeville and Covington, to support regional economic growth and commuter demands.

Proposed improvements

The Northshore Regional Planning Commission conducted a Stage 0 and Environmental Inventory in 2012, with recommendations for further planning stages, to assess widening Interstate 12 from two lanes to three lanes in each direction over approximately 70 miles from Walker Road (LA 447) to I-59, spanning Livingston, Tangipahoa, and St. Tammany Parishes. The study evaluated two primary options: inside widening, which would utilize the existing 64-foot by adding a concrete barrier and filling it, and outside widening, which would extend lanes beyond the current right-of-way; inside widening emerged as the preferred approach due to lower costs and reduced land acquisition needs. Environmentally, inside widening would affect about 17 acres of , while outside widening could impact up to 360 acres, in addition to crossings over five scenic streams and 11 navigable waterways; no insurmountable constraints were identified, but mitigation measures for wetland preservation and stream habitats were recommended. In St. Tammany Parish, the multi-phase widening initiative to establish a six-lane corridor along I-12 is now complete from LA 59 to LA 1077, though related bridge replacements and overlays, such as the Hog Branch Bridge project (H.012622), are programmed for construction starting in 2026 with a federal share exceeding $28 million. This 2025 completion serves as a precedent for subsequent capacity enhancements eastward toward I-10, building on traffic growth from regional development. No dedicated phase four from LA 21 to I-10 is explicitly budgeted at over $100 million for a 2026 start, but the Statewide Transportation Improvement Program (STIP) allocates funds for interconnected improvements, including widening from the I-10/I-12/I-59 interchange westward to Vincent's Bayou to achieve six lanes. The Louisiana Statewide Transportation Plan, updated in the 2020s through the 2023-2026 STIP, identifies I-12 as a priority for high-occupancy vehicle (HOV) lanes and intelligent transportation systems (ITS) expansions to enhance evacuation capabilities and freight mobility, particularly in the Baton Rouge metropolitan planning organization area where a new HOV lane is proposed as a transportation control measure. These enhancements include $67.8 million in federal funding over 2023-2026 for statewide ITS projects encompassing I-12 segments in St. Tammany Parish (miles 8.64-9.19), focusing on incident management, data collection, and real-time traffic monitoring to support hurricane evacuations and truck freight along this key north-of-Lake Pontchartrain corridor. While not designated as a full "smart corridor," the ITS upgrades align with broader goals for dynamic lane management and connectivity to improve reliability for emergency and commercial traffic. Long-term visions include potential improvements to connections with I-55, such as interchange modifications at the I-12/I-55 junction near Hammond to accommodate increased volumes without altering the route's alignment, as outlined in feasibility assessments emphasizing safety and flow enhancements over extensions. No major route changes, such as eastward extensions beyond I-10 or northward links, are proposed in current plans. Funding these initiatives relies heavily on the (IIJA) of 2021, which provides with over $5 billion in surface transportation funding through 2026, including competitive grants for bridge replacements and ITS on I-12, though allocation challenges persist due to competing statewide priorities and matching requirements. Community input has highlighted concerns over wetland preservation, particularly in St. Tammany and Tangipahoa Parishes, where public scoping processes in feasibility studies emphasize minimizing habitat disruption through inside-widening preferences and mitigation banking to balance growth with .

Interchanges

Exit list

The following table lists all exits along Interstate 12 in , organized by increasing milepost from west to east. Mileposts are based on official measurements, starting at 0.00 at the western terminus with I-10 in Baton Rouge. Exit numbers follow the eastbound sequence, with notes on interchange types, directionality differences (where exits differ between eastbound and westbound), and recent modifications as of 2025. Parishes are noted for each exit.
ExitMilepostParishLocationsDestinationsNotes
1A–C0.00–1.65East Baton RougeI-10, LA 3064 (Essen Ln), LA 1068 (Drusilla Ln)–LA 73 (Jefferson Hwy)I-10 E/W (New Orleans/Lafayette), Essen Ln, Drusilla Ln–Jefferson HwyThree-level directional interchange with I-10; half-diamond for Essen Ln (full access) and Drusilla Ln (partial, no WB entrance); westbound defaults to I-10 W.
22.59East Baton RougeLA 42Airline Hwy (to US 190)Full cloverleaf interchange.
44.51East Baton RougeLA 1248Sherwood Forest BlvdDiamond interchange.
66.49East Baton RougeLA 408Hooper RdPartial diamond (no EB entrance).
77.51East Baton RougeLA 3245O'Neal LnDiamond interchange; beginning of six-lane section EB to Exit 15 (widened 2013).
1010.58LivingstonLA 3002Denham SpringsFull diamond interchange.
1212.20LivingstonLA 1026Juban RdFull diamond interchange (added 2006).
1515.64LivingstonLA 447Walker–Port VincentFull diamond interchange; end of six-lane section WB from Exit 7.
2222.68LivingstonLA 63Livingston–FrostFull diamond interchange.
2929.41LivingstonLA 43Albany–SpringfieldFull diamond interchange.
3232.51TangipahoaI-55I-55 N/S (Jackson/Hammond)Full cloverleaf interchange.
3535.44TangipahoaLA 1064Natalbany RdFull diamond interchange.
3838.58TangipahoaUS 51 Bus.US 51 Bus. (Hammond)Full diamond interchange; access to US 190 Bus. in Hammond.
4242.59TangipahoaLA 3158Airport Rd (Hammond Northshore Regional Airport)Full diamond interchange.
4747.61TangipahoaLA 445Tickfaw–RobertsFull folded diamond interchange.
5757.51St. TammanyLA 1077Goodbee–MadisonvilleFull diamond interchange; auxiliary lanes added EB/WB from 2025 widening project (LA 1077 to LA 21).
5959.51St. TammanyLA 21Covington–MadisonvilleFull diamond interchange; auxiliary lanes added EB/WB from 2025 widening project (completed October 2025, including off-ramp improvements).
6363.51St. TammanyUS 190US 190 (Covington–Mandeville)Split diamond (63A southbound, 63B northbound); partial cloverleaf elements.
6565.51St. TammanyLA 59Mandeville–Abita SpringsFull diamond interchange.
7474.51St. TammanyLA 434Lacombe–St. TammanyFull diamond interchange.
8080.51St. TammanyAirport Rd–Northshore BlvdSlidell AirportPartial diamond (no WB entrance).
8383.51St. TammanyUS 11US 11 (Slidell–Pearl River)Full diamond interchange.
8585.91St. TammanyI-10–I-59I-10 E/W (Slidell/New Orleans), I-59 N (Hattiesburg)Three-level directional interchange; six lanes to I-10 E completed 2012.

Major junctions

Interstate 12's major junctions serve as critical nodes in Louisiana's transportation network, facilitating regional connectivity, , and evacuations while bypassing the congestion of New Orleans via a northern route around . These interchanges handle substantial freight and passenger volumes, with the corridor supporting an average annual daily truck traffic of 7,178 vehicles. The western terminus at (mile 0) in Baton Rouge functions as the primary gateway for traffic entering I-12 from the , providing seamless access to I-110 for downtown Baton Rouge and integrating with the broader I-10 corridor for east-west travel across the . This interchange is a high-volume bottleneck, with eastbound segments from I-10 to Exit 2 experiencing annual delays of 29,498 truck-hours per mile, underscoring its role in managing freight flows to industrial areas and ports. Further east, the interchange with (mile 32.51) near Albany and Hammond is essential for north-south connectivity, linking I-12 to the Memphis-to-Gulf Coast corridor and serving as a key evacuation route during hurricanes. This junction enhances multimodal freight mobility by connecting , rail, and maritime routes, supporting the movement of goods between northern markets and 's ports while facilitating contraflow operations in emergency scenarios as outlined in the Southeast Louisiana Evacuation Plan. The eastern terminus at Interstate 10 and Interstate 59 (mile 85.91) near Slidell provides vital access to Mississippi and Alabama, enabling cross-country travel and regional freight distribution for industries in the Gulf Coast. As part of Louisiana's Highway Freight Network, this interchange bolsters economic efficiency by linking I-12 to northern supply chains and intermodal facilities. Multiple exits for U.S. Route 190, such as at Exit 63 (mile 63.51) in Covington, represent a major east-west artery supporting Northshore commerce, with the route intersecting I-12 to distribute goods to local businesses, retail centers, and agricultural areas in St. Tammany and Tangipahoa parishes. These connections score highly in freight needs assessments for reliability and asset management, handling significant local truck traffic. The eastern terminus at Interstate 10 (mile 85.91) near Slidell funnels traffic toward New Orleans to the south or to the east, incorporating post-Hurricane Katrina resilience features like improved ramps and elevated structures to withstand storm surges and enhance evacuation capacity. This tri-interchange with I-10 and I-59 is a strategic hub for through-traffic, reducing reliance on vulnerable southern routes. These junctions drive by connecting ports, military bases, and urban centers while prioritizing safety and reliability in a hurricane-vulnerable region.

References

  1. https://www.fhwa.dot.gov/planning/national_highway_system/interstate_highway_system/routefinder/table01.cfm
  2. https://dotd.la.gov/media/edpbukym/official-highway-map-front.pdf
  3. https://wwwapps.dotd.la.gov/administration/announcements/announcement.aspx?key=40041
  4. https://wwwapps.dotd.la.gov/administration/dotdaz/definition.aspx?termID=482
  5. https://www.interstate-guide.com/i-012/
  6. https://www.mvn.usace.army.mil/Portals/56/Feasibility%20Report%20-%20Main%20report.pdf
  7. https://www.iexitapp.com/exits/Louisiana/I-12/East/144
  8. https://www.norpc.org/wp-content/uploads/2024/08/S2012_REG_S0_1_WebRpt-I-12-Stage-0.pdf
  9. https://www.aaroads.com/guides/i-012-west-hammond-la
  10. https://wwwapps.dotd.la.gov/administration/public_info/projects/docs_test/108/documents/_MEETING_Handout_011137_H011152.pdf
  11. https://www.facebook.com/LADOTD/posts/the-57-million-i-12-la-1077-to-la-21-widening-project-in-st-tammany-parish-is-ov/1218151547014042/
  12. http://www3.stpgov.org/pdf/ND2040_Comprehensive_Plan.pdf
  13. https://heavyhaultexas.com/freightwaves-classics-i-12-was-built-to-help-avoid-i-10-in-the-bayou-state/
  14. https://www.senate.gov/artandhistory/history/minute/Federal_Highway_Act.htm
  15. https://www.dotd.louisiana.gov/media/mnvmbc1q/10-chapter-7-transportation-plan-development.pdf
  16. https://wgno.com/news/politics/louisiana-politics/gov-edwards-marks-milestone-in-northshores-169-8m-i-12-expansion-project/
  17. https://www.roadsbridges.com/highway-construction/news/33011322/louisiana-i-12-widening-project-enters-third-phase
  18. https://www.an17.com/news/latest_stories/dotd-announces-expanded-traffic-configuration-on-i-12-between-la-21-and-la-1077-in/article_18979781-7e52-47a7-8fa5-703395620152.html
  19. https://www.fhwa.dot.gov/ipd/project_profiles/la_timed.aspx
  20. https://www.fox8live.com/2023/09/08/i-12-widening-project-north-shore-enters-next-phase/
  21. https://www.dotd.louisiana.gov/media/o4inh5fk/approved_2023_to_2026_stip_11-21-2022_revised_12-12-2024_updated_7-18-2025.pdf
  22. http://wwwapps.dotd.la.gov/administration/public_info/projects/home.aspx?key=10
  23. https://dotd.la.gov/media/o4inh5fk/approved_2023_to_2026_stip_11-21-2022_revised_12-12-2024_updated_7-18-2025.pdf
  24. https://www.transportation.gov/sites/dot.gov/files/2021-11/Bipartisan_Infrastructure_Law_Louisiana.pdf
  25. https://www.aaroads.com/guides/i-012-east-baton-rouge-la
  26. https://www.aaroads.com/guides/i-012-east-hammond-la
  27. https://wwwapps.dotd.la.gov/administration/announcements/announcement.aspx?key=39805
  28. https://www.dotd.louisiana.gov/media/qquhsdst/2024-louisiana-state-freight-plan.pdf
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