Columbia’s HOV Future – Part 2 (I-20 Northeastern Richland County)

This is the second in a series of looking at the various stretches of highway in Central South Carolina that the SC Dept of Transportation wants to look at for traffic improvements.

Today’s area of interest is Interstate 20 from I-77 to Spears Creek Road. Here’s some stats on the stretch of highway:
Start: Exit 76 A and B (I-77 and Alpine Roads)
End: Exit 82 (Spears Creek Rd)
Length: 6 miles (per the AP)
Interchanges:

• Exit 76 A – I-77
• Exit 76 B – Alpine Rd.
• Exit 80 – Clemson Rd.
• Exit 82 – Spears Creek Church Rd.

Lanes:

• 2 Lanes in Both Directions

Notes:

• This section of I-20 leads to one fastest growing areas in the region, Northeast Columbia.
• Northeast Columbia has numerous traffic issues, due to a lack of planning and insufficient capacity. The existing roads are overburdened by any stretch of the imagination.

Map

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Biggest Problem:
Massive undercapacity. I-20 being two lanes for this area of the state makes it woefully unable to deal with the commuter traffic and regional/national traffic that uses this highway as the main east-west route in South Carolina. This stretch of road starts with the bottleneck of 3 lanes merging to two along with traffic merging from I-77.

Possible Solutions:
Additional Lanes: Extremely Likely. This stretch of road has plenty of land on both sides of the road in addition to plenty of median space to add lanes in the middle of the road as well.
Converting Current Lanes to Carpool Lanes: Not Happening. Because there are only two lanes each way, there’s no way that there’s only going to be one lane each way for trucks/non-commuters and one lane for commuters. But then there would be strong incentive to carpool, but the road would not be interstate standard at that point.
Converting Current Lanes to HOT Lanes: Unlikely. This would toll the road, but you run into the same problem of having only one lane in each direction. However, you could toll the entire road, but they’re trying to avoid this and this would be rather politically unpopular.

Most Likely Solution: Expand to three lanes each direction, with one lane designated HOV. HOT would not have the political clout to stand on its own (there are few other potential areas for HOT lanes in the region, so you wouldn’t have any economies of scale). However, HOT lanes would allow for financing the lanes much easier.
Best Solution: Northern Virginia-style HOT lanes and an additional lane each way. There’s plenty of room to do this, as there’s enough space on each side AND in the median to add both another lane of mainline traffic with a NoVA style reversible two-lane HOV/HOT lane. Making it HOT would enable the project to get additional money to expedite construction and financing.

This is a short stretch of road, compared to the other areas that are looked at, but has really really been used beyond the scope of what it was intended to do. The SCDOT did not anticipate the growth in Northeast Richland, and as a result, this area of I-20 suffers from daily congestion. Exit 80 (Clemson Rd.) is also situated at the top of a hill, so traffic will back up here, both in the morning and at night. The nice thing is that there is enough space and clearance at this exit that it could easily accommodate two lanes of reversible traffic.

Columbia’s HOV Future – Part 1 (I-26 Lexington County)

As an update, The State has posted a somewhat more in-depth article on the proposal for HOV lanes in the Central SC area. They didn’t go into any more specifics than what you could get from the wire service article I posted yesterday, except they interviewed one person, someone who works for local governments. Not exactly an expert on transportation issues, but this is a newspaper. Yet, Keven Cohen thinks this is a good article. Not exactly Kevin.

But onto what I want to, which is what The State should be doing, a more in-depth look at what the situation currently is and what can be done.

The first area I want to discuss is the stretch of I-26 in Lexington County. Here’s some stats on the stretch of highway:
Start: Exit 108 (I-126 into downtown Columbia)
End: Exit 116 (I-77, US 21, 321 and 176 exits)
Length: 7.22 miles (per the AP)
Interchanges:

• Exit 108 A – Bush River Road (Part of Malfunction Junction)
• Exit 108 B – I-126 (Part of Malfunction Junction, also a left exit)
• Exit 110 – US 378 (Exit terminates at one of the few SPUI interchanges in South Carolina, leading to some… interesting driving maneuvers.)
• Exit 111 A & B – US 1 (Cloverleaf interchange with VERY short merge lanes)
• Exit 113 – SC 302 (Exit to Columbia Metro Airport, mingles with frontage roads)
• Exit 115 – US 21, 321 and 176
• Exit 116 – I-77 (Another left exit with two lanes)

Lanes:

• 3 in both directions between Exits 110 and 113.
• 4 Lanes westbound (northbound) between Exits 110 and 108.
• 4 Lanes Eastbound (southbound) at mile 114 to Exits 115/116

Notes:

• This stretch of highway never goes into Lexington (as The State article says), it’s stays well to the east of Lexington city, while remaining the whole time in Lexington County, which is a big difference)
• This stretch of highway was widened to three lanes already, very much limiting the ability to expand or even shift the alignment to accommodate any changes.
• Originally, at Exit 108, it was two lanes into Columbia (via I-126) and ONE lane through for I-26. This suggests that the original alignment was to continue closer to Columbia or for I-26 to move straight and I-126 to exit left, but the geography of the area, in particular the Saluda River, prevented that from happening.
• The cheapest gas in Columbia can be found at the Bush River Exit.

Map

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Biggest Problem:
Old Interchanges with Poor Alignment. Most problems on this stretch of highway occur at the exits, in particular, the US 378 exit (traffic will back up on the ramp and to the highway due to poor clearance for right-hand turns onto US 378 ) and the US 1 Exit (sharp turns and a very short merge between the first on-ramp and the second off-ramp for this cloverleaf style interchange).

Malfunction Junction (I-20/26/126/Bush River Rd./St. Andrews Rd.) is a completely different story and requires an entry by itself.

Possible Solutions:
Additional Lanes: Not likely. This is due to the expansion already completed in the area and the quasi-urban surroundings on I-26 especially between US 378 and SC 302. However, this wouldn’t solve the interchange problems without dedicated lanes for each exit. This is possible for US 378, unlikely for US 1 or SC 302. However, past I-77 to the south, an additional lane can and should be added as this becomes a bottleneck for traffic to Charleston and I-95 (Florida and Georgia coast).
Converting Current Lanes to Carpool Lanes: Most Likely, but still difficult. There would need to be some realignment of the road to accommodate separating the carpool lanes from mainline traffic. It helps here that traffic is not too bad that the loss of a lane would seriously tie up traffic. But due to the proximity of the exits, it would be difficult to allow for traffic to get off at multiple exits. There may have to be limits on which exits HOV vehicles would be allowed to enter or exit at.
Converting Current Lanes to HOT Lanes: Unlikely. The proximity of the exits would make putting tolls in a problem, requiring a station every mile or so. Also exacerbates the entrance, exit areas problems with additional merges and lane changes. The other problem with HOV/HOT lanes is that it wouldn’t allow for traffic to stay separated past I-77 (east/southbound) due to the left exit. Traffic would have to blend or merge before that point or result in a much more costly fly-over and touchdown on the other side of the 26/77 interchange.

Most Likely Solution: Convert left lane to Atlanta-style HOV lane.
Best Solution: Realign US 378 and US 1 exits to allow for better flow of traffic. No HOT/HOV lanes.

Outside of the merges with exits, there are not problems with traffic flow itself. It also helps that I-77 takes a good portion of northbound traffic on the other side of the city, allowing for traffic to by-pass the city to the east. While there is some commuting from this area to other parts of the city, most commuting in this area is east-west, while this stretch of I-26 is primarily north-south. This is area of I-26 in the area with the least problems.

South Carolina Considers Carpool Lanes

From The State:

Lanes that will encourage carpooling on Interstate 26, Interstate 126 and Interstate 20 in the Midlands are being studied by the S.C. Department of Transportation as an option to relieve growing road congestion.

Less traveled HOV lanes — or High Occupancy Vehicle Lanes — would be set aside for vehicles traveling with at least one passenger. The quicker access those lanes provide have encouraged carpooling in states that have HOV lanes.

If such lanes are created, SCDOT is also studying whether to give drivers without passengers an option to pay a toll and use the less traveled lanes.

Last month, SCDOT began exploring this idea on a 22-mile stretch between Charleston and Summerville on I-26.

HOV lanes are being considered in the Midlands because of the growing suburban population in Lexington County, Northeast Richand and Irmo.

Sections of I-126 and I-20 cannot be widened. SCDOT says traffic will double by 2030.

SCDOT is studying HOV lanes for these four commutes:

• IRMO to DOWNTOWN. A 9.22 mile section of I-126 between Irmo and the Huger Street exit. This is one of the two most heavily traveled interstate highways in S.C.

• I-126 to I-26. A 7.22 mile section of I-26 starting at the I-126 interchange near Bush River Road and headed east toward Orangeburg

• I-20 to I-126. A 6-mile section of I-20, east of Interstate 77.

• NORTHEAST RICHLAND to LEXINGTON. A 14.45-mile section of I-20, west of the I-77 exchange in northeast Richland and stretching to west to U.S. 378 in Lexington County. SCDOT says this section of highway is heavily graveled and cannot be widened.

Ignoring the poor formatting of the article there are three areas they are studying:

1. I-26 to I-126 into downtown Columbia
2. I-26 from I-126 east toward Charleston
3. I-20 from Spears Creek Rd to US 378 in Lexington, a 20 mile stretch of road.

The next three days I’ll look at these three areas and see what it looks like now and what should be done. Here’s a general guideline:

• Increasing capacity is good
• Decreasing capacity is bad
• Market-based tolls are good
• Revenue-based tolls are bad
• Simplifying traffic patterns is good

We’ll start tomorrow off easy with I-26 Eastbound between I-126 and Gaston. It’ll be easy because it’s really simple to look at and critique.