An Agency Guide on Overcoming Unique Challenges to Localized Congestion Reduction Projects

APPENDIX A
CASE STUDY FACT SHEETS

Arkansas: Operation Bottleneck Program “Ask & They Will Tell”

Location:

Little Rock, Arkansas

Primary Agency:

Metroplan

Contact:

Jim McKenzie, Executive Director
mckenzie@metroplan.org
(501) 372-3300

Case Study Overview

What was the problem?

The federal government requires that metropolitan planning organizations (MPOs) report every 5 years on long-term traffic solutions. The Metroplan MPO determined that federal dollars available for transportation were not meeting local needs and they needed to look into cost-efficient solutions to improving traffic.  They also wanted to get a better idea of how bad the regional mobility problems were based on community input.

How was it solved?

A comprehensive public outreach effort – Operation Bottleneck – was launched in October 2008 to identify traffic bottlenecks as well as auto, bike, and pedestrian safety issues throughout the region. Public input was solicited via newspapers, public meetings, and the internet.

What was the outcome?

The Operation Bottleneck program received 3,000 responses in 1 ½ months, with on-line submissions constituting the highest return.  Metroplan is currently reviewing, classifying, and analyzing the feedback, and the next step will be to coordinate with local jurisdictions. This effort might also help make the case to adopt a Regional Mobility Authority to local agencies that can raise local taxes for public improvements. Other foreseeable activities include: a half-dozen corridor upgrades, an Operation Roundabout program to investigate potential intersections, two to three dozen minor spot location projects, hiring a signal timing expert to assist regional agencies with needed adjustments, and consideration of a new traffic management center. One project that has already been implemented is a $1.5 million project for intersection improvements at the Dave Ward Drive/Donaghey Avenue intersection in Conway, Arkansas.

Overcoming Key Challenges & Barriers

What were the barriers & challenges?

1. Disposition towards major projects
2. Lack of confidence in proposed solutions
3. Low-cost solution may blur the need for larger project
4. Lack of understanding of funding possibilities
5. Lack of available resources for implementation

How were they overcome?

The mindset of the MPO is now more focused on operations and management and trying to implement solutions that reduce congestion and improve air quality. The region is also pursuing a local tax dedicated to transportation improvements and believes the intense public involvement engendered during the Operation Bottleneck program will help to outline specific projects that would be received well by the community.

For more information – http://www.metroplan.org/

I-580/US-101 Connector Ramp Restriping “It’s Amazing What Some White Paint Can Do”

Location:

Marin County, California: I-580 WB to US-101 SB

Primary Agency:

Caltrans

Contact:

Bob Haus, Public Information Officer
robert_haus@dot.ca.gov
(510) 286-5576

Case Study Overview

What was the problem?

For years, the one-lane exit ramp between I-580 westbound and US-101 northbound was a daily headache for commuters. First opened in 1956, the connector operated with only one lane for more than half a century, causing one of the most infamous bottlenecks in the Bay Area. It was so notorious that the traffic monitoring company Inrix ranked it as the fourth worst bottleneck in the United States in its 2008 National Traffic Scorecard Report. The company determined that the backed-up exit ramp caused traffic to be congested for 69 hours a week. Cars passed through during peak commute hours at a puttering average of 7.6 miles per hour (mph) due to the abrupt contraction of two lanes to one lane.

How was it solved?

In the Spring of 2009, Caltrans – urged by the community – restriped the ramp, temporarily changing the shoulder into a second lane to ease the flow of traffic.

What was the outcome?

Positive results from the restriping were almost instantaneous. For 2009, the 580-101 connector ramp plummeted to the inconspicuous position of 491st on Inrix’s national bottleneck rankings as drivers experienced only 19 hours of congestion a week and averaged a speed of 14 mph during peak hours.

Overcoming Key Challenges & Barriers

What were the barriers & challenges?

1. Project champion
2. Lack of confidence in proposed solution
3. Low-cost spot solution may blur the need for larger project
4. Lack of shoulders takes away necessary refuge areas

How were they overcome?

Caltrans had a significant capital project ($10 million) to improve the ramp to a permanent dual-lane configuration as part of a bigger US-101 project. There was reluctance to implement the project; however, the public basically became the project champion for the interim restriping with their persistent outcry. The lack of shoulders was only going to be a temporary condition because of the already funded project to widen the ramp to two lanes with full shoulders.

For more information – http://bayarea.blogs.nytimes.com/2010/05/21/unclogging-a-traffic-bottleneck-in-marin/

US-90 Near Louisiana Superdome in New Orleans “Sometimes Less Is More: Creating Exit-Only Lanes”

Location:

US-90 Ponchartrain Expressway at I-10/Claiborne

Primary Agency:

Louisiana Department of Transportation

Contact:

Chris Morvant, Transportation Engineer
chris.morvant@la.gov
(504) 437-3109

Case Study Overview

What was the problem?

A section of the US-90 elevated expressway in New Orleans near the Louisiana Superdome was a chronic bottleneck, primarily due to several ramps in close proximity and one ramp (South Claiborne Avenue) that had an abrupt merge known to commonly cause driver anxiety.

How was it solved?

In a less-is-more strategy to improve traffic flow near the Superdome, state officials eliminated some through-lanes on US-90 to create exit-only lanes designed to reduce last-second merging and improve flow.  The striping changes implemented in December 2010 converted sections of two lanes into shoulders, creating exit-only lanes for I-10 East and Claiborne Avenue.

What was the outcome?

Anecdotal reports based on relatively light holiday traffic suggest that the striping changes are working. A formal study is being conducted to supplement the preliminary findings.

Overcoming Key Challenges & Barriers

What were the barriers & challenges?

1. Lack of confidence in proposed solution
2. Spot treatment will move the problem and not fix it

How were they overcome?

The proposed solution of reducing the number of travel lanes in certain areas seemed counterintuitive. The idea was to separate traffic according to where people want to go and try and eliminate the need to try and merge over, which slows things down, especially in heavier traffic. A before study showed that reducing the traffic bound for I-10 West from three lanes to two should not create a new bottleneck because more than a third of motorists exit at I-10 East.

For more information – http://www.nola.com/traffic/index.ssf/2011/01/pontchartrain_expressway_restr.html

Gateway Signal Optimization in Baltimore City “Removing Stops Means More Gos”

Location:

Baltimore City, Maryland

Primary Agencies:

Baltimore City and Sabra, Wang & Associates

Contact:

Ziad Sabra
zsabra@sabra-wang.com
(410) 737-6564

Case Study Overview

What was the problem?

Motorists commuting to and from downtown Baltimore City, Maryland along key arterials faced significant delays at closely-spaced signals. A need was identified to develop optimized signal timing plans to serve both the directional commuter peak as well as local traffic patterns and to reduce travel times, delays, stops and environmental impacts for all users.

How was it solved?

A project known as Baltimore City Gateways Signal Optimization developed optimized signal timing plans for approximately 175-signals along nine corridors. The City hired a consultant to perform all major components, including data collection, existing conditions evaluation, modeling, timing plan development, field implementation and fine tuning, and travel time studies and recommendations.

What was the outcome?

The project had a total cost of $402,500, approximately $2,300 per intersection. The net benefits from retiming the 175 gateway signals alone resulted in significant savings in reduced stops and delays, and fuel consumption; equivalent to a monetary benefit of approximately $20.4 million in the first year (see table below for performance measures).

Benefits of Optimized Gateway Timing Plans

	Vehicle Delay (hr)	Number of Stops	Fuel Consumption (gal)	CO Emissions (kg)	NO Emissions (kg)
“Before”	6,963	499,066	15,827	1,106	215
“After”	4,938	455,807	14,042	982	191
Improvement	2,025	53,259	1,785	125	24
% Improvement	29%	11%	11%	11%	11%
Annual Benefit	$16,221,490	$372,813	$3,213,000	$436,785	$171,936
Total Benefit	$20,416,524
Approximate Cost	$402,500
Benefit-Cost Ratio	51:1

Baltimore City Signal Timing Optimization – Gateway Corridors, May 2008.

Overcoming Key Challenges & Barriers

Barriers/Challenges	How They Were Overcome
Lack of training	Hired a consultant with experience in corridor signal timing projects.
Culture of historical practices	Prior to the project the signal shop had a lot of control over signal timings; however majority control was switched to engineering.
No dedicated funding category	City obtained funding using the Congestion, Mitigation and Air Quality (CMAQ) program in addition to local funds.
Lack of available resources	Hiring a consultant supplemented available City staff.

For more information – http://sabra-wang.com/media/BaltimoreSignalTimingOptimizationITEJournalJune08RinikerSilbermanSabra.pdf

I-75/M-81 Interchange Reconfiguration “Michigan Roundabout Proves Golden”

Location:

Saginaw County, Michigan: I-75/M-81 interchange

Primary Agency:

Michigan Department of Transportation

Contact:

Louie Taylor, Delivery Engineer
TaylorLo@michigan.gov
(517) 322-6092

Case Study Overview

What was the problem?

Multiple problems existed at this tight diamond interchange. It suffered from heavy truck traffic on M-81, inefficient signal control at the ramp terminals, and safety problems as a result of sharp left turns to and from the ramps that contributed to frequent truck overturns. Backups routinely occurred and the bridge for M-81 over I-75 was in “critical condition.”

How was it solved?

Given limited resources, the state chose an innovative design approach with roundabouts replacing the tight diamond. The project included reconstruction of the bridge, roundabouts (which include bypass lanes) at the ramp terminals, and removal of the traffic signals. At $5.1 million, this solution represented a cost savings of $6 to $7 million over typical reconstruction, primarily because right-of-way needs were considerably smaller compared to other proposed alternatives.

What was the outcome?

The installation of modern roundabouts significantly reduced delay and fuel consumption, with no visible traffic backups. Ultimately, the initially lukewarm reception of the design concept was replaced by public acceptance and accolades for the completed project – including being selected as a Gold Level Winner of the 2007 National Achievement Awards sponsored by the National Partnership for Highway Quality.

Overcoming Key Challenges & Barriers

Barriers/Challenges	How They Were Overcome
Culture of historical practices	Focused discussion with management on design concept – cost savings
Lack of confidence in solution	Simulation models showing level-of-service improvement from D to A.
Getting stakeholder buy-in	Presentations to stakeholders and aggressive public involvement and education campaign including the use of special brochures, videos and newspaper editorials.

For more information – http://www.nphq.org/doc/awardnominations/2007/Michigan.doc

I-94 Lane Modification Near Lowry Tunnel “Providing Options Can Smooth Flow”

Location:

Minneapolis, Minnesota: I-94 approaching I-394

Primary Agency:

Minnesota Department of Transportation

Contact:

John Griffith
John.Griffith@state.mn.us
(651) 234-7728

Case Study Overview

What was the problem?

Congestion regularly occurred in the right lane of westbound I-94 prior to the westbound I-394 exit. This was caused by the high amount of weaving from vehicles that tended to occur from motorists trying to avoid the right lane congestion and merge just north of the Lowry tunnel where there was a lane added.

How was it solved?

The $300,000 project reconfigured the westbound lanes so that the right lane through the tunnel became an exit-only lane to I-394, the left lane became exclusively for westbound I-94 and the middle lane was split into two lanes at the tunnel exit with the left lane designated for westbound I-94 and the right lane an “option” lane between either I-94 or I-394. The lane modification was designed to provide better access to I-394, reduce congestion in the right lane, and improve safety in the area by eliminating the last-minute weaving into the right lane.

What was the outcome?

Minnesota DOT is gathering data from traffic detectors to regularly assess the performance of this project which was completed in September 2010. Preliminary results show positive increases in throughput during the AM peak and no significant effect in the PM. The safety effects will be evaluated at a later date.

Overcoming Key Challenges & Barriers

Barriers/Challenges	How They Were Overcome
Culture of historical practices	Education on benefits in short-term goals.
Lack of confidence in solution	Review of traffic analysis and other data supports the solution.
Spot treatment won’t fix the problem	Commitment to monitor for one year and make necessary changes with future programmed project one year out.
Hesitancy to implement non-standard solution	Review of standards and how project does not violate driver expectation and, where design exception needed, determine likely outcomes.

For more information – http://www.dot.state.mn.us/metro/projects/cmsp/pastprojects.html

TH-100 at St. Louis Park Project “Smaller can Sometimes Equal Bigger”

Location:

Minneapolis, Minnesota: TH-100 from 36th St. to I-394

Primary Agency:

Minnesota Department of Transportation

Contact:

Lars Impola, Metro District Traffic Engineer
Lars.Impola@state.mn.us
(651) 234-7820

Case Study Overview

What was the problem?

The section of TH-100 from 36th Street to I-394 was the last remaining segment of original 1937 construction. A bottleneck existed with a four-lane section of freeway sandwiched between two six-lane segments. This bottleneck caused congestion during both the AM and PM peak periods in both directions. MnDOT found that this part of TH-100 was exposed to congestion for the longest amount of time per day of the Minneapolis/St. Paul metro area. Additionally, recent crash studies indicated that several of the substandard ramps were causing an unacceptable number of correctable crashes. Urgency was added to this project because it could act as a reliever to the upcoming I-35W/MN-62 reconstruction.

How was it solved?

MnDOT converted the shoulders of TH-100 to a general purpose through lane northbound and a collector-distributor lane southbound. These lanes were designed to increase the existing capacity and throughput. The existing interchanges were also reconfigured to correct substandard ramp entrances. Construction was completed in 2006 at a cost of $7.1 million.

What was the outcome?

The table below shows that significant mobility benefits were realized; however, due to downstream bottlenecks and a substandard ramp, crashes have increased within the area of influence of this project. This project won an award in Minnesota for public project of the year and provided a greater level of mobility benefit than a parallel design-build project on I-494 that cost $138 million to construct.

Project Cost (millions)	Reduction (Annual Hrs of Delay)	Increase in Traffic Flow (vehicles)	Decrease in Peak Period Congestion	Peak Period Travel Speed1	Crash Reduction	Benefit-Cost Ratio2
$7.1	1,063,500	AM peak: 8,770	AM: 5 miles	AM: 45-50 mph	49% increase-SB	13:1
		PM peak: 11,918	PM: 6 miles	PM: 45-50 mph	17% increase-NB

¹ The daily peak period is 10 hours, AM peak from 6:00 to 10:00AM and the PM peak from 2:00 to 7:00PM ↑
² Based on 7 year congestion savings ↑

Overcoming Key Challenges & Barriers

Barriers/Challenges	How They Were Overcome
Culture of historical practices	Education on benefits in short-term goals.
Lack of confidence in solution	Review of traffic analysis and other data supports the solution.
Spot treatment won’t fix the problem	Commitment to monitor for one year and make necessary changes with future projects.
Hesitancy to implement non-standard solution	Review of standards and how project does not violate driver expectation and, where design exception needed, determine likely outcomes.

For more information – http://www.dot.state.mn.us/metro/programmanagement/pdf/beforeafter.pdf

I-44/Route 13 Diverging Diamond Interchange “The Early Bird Gets the Worm”

Location:

Springfield, Missouri: I-44 at Route 13

Primary Agency:

Missouri Department of Transportation

Contact:

Don Saiko, Project Manager
Donald.Saiko@modot.mo.gov
(417) 895-7692

Case Study Overview

What was the problem?

The I-44/Route 13 interchange had a number of issues including: traffic congestion, left-turns backing up and blocking thru traffic, and 73% of crashes are rear-end and left-turn right angle. MoDOT had limited funds to improve this location and considered three options: (1) widen the bridge with dual lefts; (2) replace bridge with a Single-Point Urban Interchange (SPUI); or (3) convert the existing interchange to a Diverging Diamond Interchange (DDI), which would be the first in the United States.

How was it solved?

MoDOT chose to build the first DDI because it was cheaper to build ($3.2 million vs. $9 million for a SPUI) and maintain. The DDI option also was quicker to build (6 months vs. 1½-2 years) primarily because it utilized the existing bridge and required no additional ROW.

What was the outcome?

MoDOT evaluated the DDI on traffic operations, safety & public perception

Traffic Operations	Safety	Public Perception
Left-turn movements within the DDI had a noticeable decrease in delay & queuing Through movements within the DDI had a slight increase in travel time Over-dimension loads up to 18 ft wide and 200 ft long have successful moved Overall traffic flow is better and typical 1 mile backups during the AM and PM and 2-3 mile backups during weekends and holidays have been eliminated	Total crashes down by 46% in the first year of operation Left turn type crashes were eliminated and left turn right angle crashes were down 72% Rear-end type crashes were down slightly The DDI’s post-construction crash types are similar to any other signalized intersection	A very high percentage (80+) expressed that traffic flow had improved and delay had decreased A very high percentage (87%) said that crash were more likely to occur at the previous diamond than the new DDI A very high percentage (80%) expressed that larger vehicles and pedestrian/bike movements through the DDI were better or similar to a standard diamond

Overcoming Key Challenges & Barriers

Barriers/Challenges	How They Were Overcome
Project champion	The project engineer became champion and garnered by internal (upper MoDOT management) and external (business) support.
Project planning and programming requirements	The FHWA required that a modified Interstate Access Justification (IAJ) be done 2 weeks before the project was let; however, project staff was able to finish the new analysis prior to the deadline.
Lack of confidence in the proposed solution	Project staff utilized an enhanced level of traffic analysis and public outreach (particularly with Wal-Mart) including a simulation model and project video designed to showcase how a DDI operates.
Hesitancy to implement solution that does not follow standards	The project engineer had to convince MoDOT Central Design staff that the pedestrian access would work well through the middle of the DDI instead of on the outside like traditional diamonds.

For more information – http://library.modot.mo.gov/RDT/reports/TRyy1013/or11012.pdf

Freeway Bottleneck Removal in Texas “Championing Low-Cost Projects”

Location:

Dallas-Fort Worth, Texas: 17 projects

Primary Agency:

Texas Department of Transportation

Contact:

Stan Hall, Advance Planning Engineer
Stan.hall@txdot.gov
(214) 320-6155

Case Study Overview

What was the problem?

The DFW area has the most extensive freeway system on a per-capita basis when considering lane-miles and interchanges. Over the last 20 years, recurrent congestion appeared at many locations and in areas with no major capital improvements in the long-range plan. TxDOT developed a number of low-cost projects to address these localized congestion areas, also commonly called bottlenecks. Most improvements were implemented with discretionary funds and project champions were a key to success.

How was it solved?

Some of the typical low-cost solutions implemented in the DFW region included: restriping, reducing lane widths and converting shoulders in order to provide additional travel lane(s) for a short section, auxiliary lanes, and ramp modifications (e.g., closure, reversal and/or metering).

What was the outcome?

See Transportation Research Record No. 1925, 2005, pp. 66-75.

Evaluations of the 17 case study projects revealed benefit-cost ratios from 3 to 400:1, based on measured travel time savings. Typical project costs ranged from $5,000 to $2.7 million dollars with most under $1 million. The project also improved safety with an average 35% reduction in injury crash rates after congestion mitigation from the bottleneck improvement. Since TxDOT took the time to evaluate the project outcomes, positive media attention and public feedback from commuters often followed.

Overcoming Key Challenges & Barriers

Barriers/Challenges	How They Were Overcome
Project Champion	Support for low-cost bottleneck projects was at a high level, including the District Engineer and MPO Director.
Project planning and programming requirements	Most solutions were over a short distance where air quality and environmental requirements were not necessary.
Lack of training	The Texas Transportation Institute developed a Freeway Bottleneck workshop that taught TxDOT about successful bottleneck removal.
Lack of incentives/recognition	TxDOT leadership formalized recognition for successful projects, rewarding Area Engineers during annual performance evaluations.
Design exception process is difficult	Over time, TxDOT gained the trust of FHWA staff by evaluating projects and showing the positive operational and safety benefits.

For more information – http://www.bottleneckworkshop.org/