Interstate 12 functions as a bypass route for Interstate 10 north of Lake Pontchartrain and the New Orleans metropolitan area. Although an intrastate route, the freeway provides a significant role in cross-country travel.
The freeway splits with Interstate 10 in Baton Rouge as a busy commuter route through suburban areas east to Denham Springs. Continuing east, I-12 becomes more rural through areas of pine forest, but still with moderate traffic given it accommodates just four overall lanes.
Interstate 55 crosses paths with Interstate 12 outside Hammond, the largest city between Baton Rouge and Slidell. The freeway passes south of the city street grid and quickly exits the area toward Covington and the Lake Pontchartrain North Shore communities of Madisonville and Mandeville. There U.S. 190 ties in from the north end of Lake Pontchartrain Causeway, a lengthy toll bridge leading south to Metairie and Jefferson Parish west of New Orleans.
The remainder of Interstate 12 leads east through St. Tammany Parish to Slidell and the junction with Interstate 10 and 59 north. The freeway passes through North Slidell and suburban areas before defaulting onto I-10 east across Pearl River Wildlife Management Area into Mississippi.
Parallel U.S. Routes
Interstate 12 replaced U.S. 190 as the through route north of Lake Pontchartrain. U.S. 190 parallels I-12 to the north from Baton Rouge east to Covington and to the south between Mandeville and Slidell.
According to the journal Roads and Bridges, the I-12 corridor should be extended westward. They describe it as follows: "Interstate 12 Houston to Austin: These metropolitan areas have grown rapidly. Less than 100 miles, this route would require upgrading from Austin to Interstate 10 along the state route 71 corridor." SH 71 is a four-lane roadway for its entire length, with portions already upgraded to expressway standard.
One upgrade along the SH 71 corridor is the SH 71 Express Project in Austin. Construction between early 2015 and late 2016 upgrades 3.9-miles of the highway, from Presidential Boulevard at AUS Airport to SH 130 near Onion Creek, to a limited access toll road. Work will add two new toll lane overpasses at FM 973 and SH 130.
Interstate 12 was completed between U.S. 61 (Airline Highway) at Baton Rouge and Interstate 55 at Hammond in 1969. The western most two miles of Interstate 12 opened in conjunction with Interstate 10 east from College Drive in 1965.2 Interstate 10 southeast from I-12 would not be completed until 1974, resulting in traffic defaulting from I-10 east onto I-12 and U.S. 61 until 1969.
In 1993, the Louisiana State Legislature passed a resolution declaring Interstate 12 the West Florida Republic Parkway. This name stems from the 74 day West Florida Republic existence that occurred between an 1810 revolt against Spain and the forced annexation of the eight parishes into the Louisiana Purchase by the United States. During mid-November of 2003, signs were installed proclaiming the highway the West Florida Republic Parkway.1
Western Terminus - Interstate 10 - Baton Rouge, Louisiana
Perspective from Interstate 12 west
Entering the half diamond interchange (Exit 1C) with Louisiana 1068 (Drusilla Lane) and 73 (Jefferson Highway), Interstate 12 makes the final approach to Interstate 10. Photo taken 05/19/14.
Four lanes of Interstate 12 proceed west from the Essen Lane on-ramp to the three-wye interchange (Exit 1A) with Interstate 10. A lane drop occurs for the eastbound ramp back to New Orleans. Photo taken 05/19/14.
The westbound mainline of I-12 defaults onto Interstate 10 west ahead of the commercialized interchange with College Drive. Downtown Baton Rouge lies five miles to the northwest. Photo taken 05/19/14.
Historical Perspective from Interstate 12 west
Interstate 12 west at the off-ramp to LA 1068 (Drusilla Lane), 1.5 miles from the terminus. Most signs for Interstate 12 in Baton Rouge were changed to Clearview font based signs by 2013. Photo taken 01/04/09.
This set of signs for Interstate 10 and Exit 1A was carbon copied by 2013. There are no end Interstate 12 assemblies posted otherwise. Photo taken 01/04/09.
A sweeping flyover ramp (Exit 1A) carries motorists back southeast onto Interstate 10 as the mainline advances onto I-10 west with three lanes. Photo taken 01/04/09.
Older signs displayed at Exit 1A from before expansion of I-12 west to three lanes for I-10 west. Vidcap taken 01/18/96.
Perspective from Interstate 10 east
Interstate 10 advances east from the parclo interchange (Exit 158) with College Drive 1.5 miles to split with Interstate 12 at Exit 159. Photo taken 05/19/14.
A fourth eastbound lane emerges from the College Drive on-ramp as Exit 159 prepares to depart with three lanes for Interstate 12 east to east Baton Rouge, Denham Springs and Hammond. Photo taken 05/19/14.
Interstate 12 progresses east from Baton Rouge as a busy commuter route to Walker and the default through route for points east along the Gulf Coast. Interstate 10 remains busy with commuter traffic through to Gonzalez. Photo taken 05/19/14.
Interstate 12 east separates from Interstate 10 east. Hammond lies 40 miles to the east via I-12 while I-10 east reaches LaPlace in 47 miles and New Orleans in 71 miles. Photo taken 05/19/14.
The first eastbound Interstate 12 reassurance shield appears immediately east of the Exit 159 gore point from I-10 east. Drivers reach a half diamond interchange (Exit 1B) with LA 3064 (Essen Lane) in one mile. Photo taken 05/19/14.
Historical Perspective from Interstate 10 east
Interstate 10 east at Exit 158 for College Drive, which is named for Baton Rouge Community College. The split with Interstate 12 eastbound lies 1.50 miles ahead. Photo taken by Eric Stuve (12/17/02).
Diagrammatic sign formerly posted along Interstate 10 east for the impending split with Interstate 12. Sound walls were erected along this stretch in 2002.
All signs for I-12 along eastbound were replaced by 2013. Photo taken by Eric Stuve (12/17/02).
A sign replacement project underway during the spring 2000 coincided with expansion of Exit 159 to three lanes. Photo taken by Jeff Royston (05/27/00).
Previous placed diagrammatic overhead for the Interstate 10 and 12 split showing just two lanes for Exit 159 instead of three. Vidcap taken 01/22/96.
Interstate 12 begins as Interstate 10 turned southeastward toward Gonzales, La Place and New Orleans. Suburban expansion of Baton Rouge spread eastward along the Interstate 12 corridor through to Exit 10 / Louisiana 3002 at Denham Springs. Photo taken by Eric Stuve (12/17/02).
Perspective from Interstate 10 west
Interstate 10 sees a lane drop for Interstate 12 east (Exit 159) beyond the diamond interchange (Exit 160) with Louisiana 3064 (Essen Lane). Photo taken 05/19/14.
Interstate 10 bisects a wooded area proceeding the three-wye interchange (Exit 159) with Interstate 12 east. I-10 through traffic reduces to two lanes in each direction through the exchange. Photo taken 05/19/14.
Interstate 12 east serves a bevy of commuter traffic through the Southmoor, Cedarcrest and Sherwood neighborhoods areas of the city through to Denham Springs. Photo taken 05/19/14.
Exit 159 leaves Interstate 10 west for Interstate 12 east to Hammond and the Northshore of Lake Pontchartrain. Photo taken 05/19/14.
Historical Perspective from Interstate 10 west
A look at I-10 west at LA 3064 (Exit 160) before expansion of both the freeway to six lanes and off-ramp to two lanes. LA 3064 comprises a 1.86-mile state highway connecting LA 73 and 427. Photo taken by Chris Patriarca (04/13/03).
This sign bridge was removed in 2011 when I-10 was expanded to incorporate a concrete barrier median. Photo taken by Chris Patriarca (04/13/03).
Interstate 10 west at Interstate 12 was upgraded to urban design standards here in 2011. Photo taken by Chris Patriarca (04/13/03).
The first of in a series of Exits 85A/B/C guide signs on Interstate 12 stands beside the U.S. 11 underpass at Exit 83. Photo taken 05/09/15.
Construction along Interstate 12 completed in 2012 added a lane in each direction between U.S. 11 and Exit 85 with Interstates 10 and 59. The third eastbound lane added defaults onto I-10 west leading south to New Orleans. Photo taken 05/09/15.
Interstate 10 angles southwest from Slidell across Lake Pontchartrain into New Orleans East. The route doubles for commuters between the Northshore and city center. Photo taken 05/09/15.
Eastbound I-12 at the departure of Exit 85A for I-10 west. Interstate 10 overtakes the ending I-59 ahead of four interchanges for the Northshore city of Slidell. Photo taken 05/09/15.
Interstate 59 stems north from the eastern turn of Interstate 10 to leave the Slidell area ahead of Picayune, Mississippi. I-59 travels 11.48 miles to the state line near Nicholson and reaches Hattiesburg in 73 miles. Photo taken 05/09/15.
Historical Perspective from Interstate 12 east
This sign was one of several installed during a spring 2000 replacement project at Interstates 10, 12 and 59. It was replaced with a new overhead when I-12 was widened on the north side of Slidell. Photo taken by Eric Stuve (12/17/02).
Approaching the Louisiana 1091 overpass, I-12 entered its final half mile ahead of Interstate 10 and 59. Louisiana 1090 and 1091 parallel the Interstate 10/59 north-south alignment through Slidell between U.S. 11 and 190. Photo taken by Eric Stuve (12/17/02).
The grassy median at Exit 85A was replaced with a concrete barrier to accommodate six-laning of Interstate 12 through to Exit 85A. The original concrete here was also paved over with asphalt. Photo taken by Eric Stuve (12/17/02).
Motorists looped away from I-12 east via Exit 85B for the northbound beginning of Interstate 59. Photo taken 10/04/01.
Perspective from Interstate 10 west
Interstate 10 spans the West Pearl River on the two mile approach to the joint terminus of Interstates 12 and 59. Photo taken 05/09/15.
The one mile guide sign for Exits 267A/B resides just west of the Louisiana Welcome Center. The Slidell welcome center reopened on June 29, 2009 after two years of reconstruction. The new facility replaced the 1978-opened center at the same location at a cost of $12 million.2 Photo taken 05/09/15.
The left-hand lane of Interstate 10 opens to allow for two lanes to New Orleans and the westbound mainline. Traffic to the right defaults onto Interstate 12 westbound (Exit 267B) in one half mile. Exit 267A departs shortly after the split of Interstate 10 from 12 for Interstate 59 north. Photo taken 05/09/15.
Interstate 12 splits and begins from Interstate 10 west. Both highways serve the immediate Slidell area with interchanges. Otherwise Interstate 12 reaches Hammond in 45 miles while Interstate 10 enters the heart of New Orleans in 38 miles. Exit 267A, the northbound ramp for Interstate 59, departs in 0.25 miles. Photo taken 05/09/15.
Historical Perspective from Interstate 10 westbound
A resigning project of Exit 267 resulted in new guide signage for all perspectives during the Spring of 2000. The product of this project saw the replacement of the original sign bridges and faded reflective signage. This photograph shows the sign bridge at the Interstate 10/12 split.
The overheads preceding the Interstate 10 and 12 split were replaced again by 2012 with Clearview-font based signs. Photo taken by Adam Froehlig (03/99).
Perspective from Interstate 12 west
The first westbound shield for Interstate 12 appears beyond the Louisiana 1091 (Robert Boulevard) overpass. Photo taken 05/19/14.
Perspective from Interstate 59 south
The first sign for Interstates 10 and 12 west (Exits 1A/B/C) posted along Interstate 59 south is this nondescript junction panel situated north of the Louisiana welcome center. Photo taken 05/09/15.
Exit 1A to the westbound beginning of Interstate 12 departs Interstate 59 southbound as it enters a directional cloverleaf interchange with Interstate 10. Interstate 12 travels west from the outskirts of Slidell to Covington and Baton Rouge. Photo taken 04/20/12.
Historical Perspective from Interstate 59 southbound
A sign bridge, gone as of April 2012, was the first to display control cities for Interstates 10 and 12 west for southbound travelers of I-59. Interstate 59 south defaults onto Interstate 10 west to New Orleans as ramps (Exit 1A) connect with Interstates 12 west and 10 (Exit 1B) east to Bay St. Louis, Mississippi. Photo taken 08/20/01.
A resigning project during Spring 2000 resulted in the removal of this overhead Exit 1B guide sign assembly. The replacement, attached to the Brown Switch Road overpass in the background, was already replaced by 2012. Photo taken 11/06/99.
Exit 267B facilitates traffic to the westbound beginning of Interstate 12.
Interstate 59 will not encounter another Interstate highway until it merges onto Interstate 20 in 160 miles near the city of Meridian, Mississippi. Photo taken 04/20/12.
Yellow and black Left Exit tabs were included in 2012 sign replacements for Interstates 12 west and 59 north. The first interchange of Interstate 12 west lies two miles away at U.S. 11 (Exit 83). I-59 also next meets U.S. 11, with the US highway joining the freeway northward to Picayune, Mississippi. Photo taken 04/20/12.