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Redesign of the I-95/I-695 interchange in Maryland uses managed express toll lanes to improve access, mobility, and safety.
| Project I-95 Express Toll Lane Mega Project, Baltimore Civil engineer Johnson, Mirmiran & Thompson, Sparks, Md. Project highlights A four-level, full-directional interchange with express toll lanes will replace left lane exits and entrances within an existing, braided interchange design. |
Barriers will separate general purpose lanes from express toll lanes, but both sets of lanes will provide all interchange options. This essentially results in a full-directional interchange for express toll lanes nested within another full-directional interchange for general purpose lanes.
Tom Warne, former president of the American Association of State Highway and Transportation Officials and former Utah transportation chief, told the Baltimore Sun that the project "rivals the complexity of some of the larger interchanges in Southern California, including one in Orange County known as ’Orange Crush.’"
This complex interchange will relieve severe congestion in the I-95 corridor north of Baltimore by allowing more capacity thanks to additional general purpose lanes and implementation of Maryland’s first ETLs.
Construction staging requires the project to be advertised in two contracts. Contract No. 1 for the I-95/I-695 interchange, currently under construction, is a $208 million project with a fast-tracked final design produced in only 10 months. The project was also accelerated by advance right-of-way acquisition, with JMT leading negotiations for right-of-way takes for 200 properties that were affected by Section 100.
"I don’t think we could have done it any faster using design-build," said MdTA Project Manager Dave LaBella.
The design for Contract No. 2 is now complete and awaiting advertisement.
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| A rendering shows the design of the four-level, full-directional interchange that will incorporate express toll lanes to help manage congestion. |
Plans to ease congestion
The Maryland Transportation Authority, in cooperation with the Federal Highway Administration and Maryland Department of Transportation, developed the I-95 master plan study with adoption occurring in April 2003. The plan focuses on approximately 50 miles of interstate highway from Baltimore to the Delaware state line. It cited the long-range transportation needs of this important segment of Maryland’s interstate system and identified four independent projects to address the future capacity and safety needs of I-95. Overall objectives were to improve access, mobility, and safety for local, regional, and inter-regional traffic.
Section 100 is considered to be the most urgent of these four projects. Located north of Baltimore, this is the most congested section of I-95 in Maryland. Traffic averages 166,000 vehicles per day (vpd). Its Level of Service (LOS) ranking is "F" (measure of congestion) during the morning and evening rush hours. Congestion on Section 100 is expected to worsen by 2025 with traffic volumes projected to increase to 225,000 vpd. This will lengthen morning and afternoon peak hour periods, as well as extend the failing LOS F hours on weekends.
JMT spearheaded the engineering efforts for Section 100 starting in June 2003 as part of the team that MdTA engaged to conduct the two-year Section 100 project planning study of the 8-mile portion of I-95 between I-895 in Baltimore City and MD 43 in Baltimore County.
Ultimately, the project planning team chose to unbraid the northbound and southbound I-95 roadways by realigning the northbound roadway entirely to the east side of the existing southbound roadway. The team also proposed unbraiding the eastbound and westbound I-695 roadways by realigning the westbound roadway entirely to the north side of the existing eastbound roadway.
Lane management strategy
Construction progresses on the I-95/I-695 interchange north of Baltimore.
Section 100 was the first project of the I-95 master plan to start construction. Its estimated total cost is $1 billion. Safety along I-95 was an important aspect of the study. To increase capacity without using a high number of contiguous lanes, which raised more safety concerns, the use of barriers to separate ETLs was necessary. The final design included four general purpose lanes and two managed lanes in each direction. The managed lanes will be constructed within the median and separated from the general purpose lanes by barriers.
The managed lanes will feature the ETL technology that charges tolls electronically to passing vehicles on an open road. Fees will be collected electronically at highway speed to eliminate traditional lines at tollbooths. The pricing plan will be structured to encourage motorists to travel during off-peak hours and will be adjusted based on the time of day and traffic conditions. The ETLs also provide flexibility for the lanes to be used in situations where major accidents, highway maintenance, or other incidents block or impede the movement of traffic on the general purpose lanes. This will help emergency response vehicles quickly navigate through this stretch of highway, even during peak hours.
The managed lanes alternate, and ETL management strategy is complex because of the complete barrier separation of the two types of lanes. All movements between the managed lanes and general purpose lanes will be provided through 16 proposed direct-connection ramps to the I-695 roadway.
Section 100 is the first project in Maryland to combine general purpose and managed lanes in the same facility. Section 100 provides access to the Port of Baltimore, Baltimore Washington International Airport, Amtrak rail service, and the local bus system. The ETLs are expected to create more consistent travel conditions, which will allow for higher levels of predictability and reliability for freight shippers and transit providers. ETLs will also mean shorter travel times for commuters, transit operators, truck drivers, and delivery services. For the bus transit system, the ETLs will provide buses with free-flow travel lanes. Improved transit times are expected to increase ridership by 6 percent.
| Project facts Design elements for the I-95/I-695 interchange impact the following:
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Public involvement was imperative for this project since Maryland would be introducing managed lanes on roadways. During the study phase, agencies and the public were invited to provide feedback on plans for Section 100. The project planning team realized that an unusually large number of stakeholders could impede a fast-track schedule, so the team proactively sought ways to predict and eliminate potential setbacks. The team recognized the complexity of the design could inhibit understanding and slow down establishment of a consensus among various stakeholders.
To simplify the explanations of the engineering plans for the public, the team provided renderings and animations of cars traveling along the proposed ramps that were used during focus group meetings, public workshops, and the public hearing. The early involvement allowed the planning team to adopt helpful public and agency comments in the beginning stages of design. This aided the public’s acceptance of ETLs along this section of the I-95 corridor.
Because of early involvement of agencies and the public, as well as a streamlined schedule, the planning team was able to fast-track design plans to 30-percent completion. The planning study was completed in the summer of 2005 and construction began in October 2006.
Construction and maintenance of Section 100 will be funded by revenue generated by the tolls collected from the ETLs, as well as other funds budgeted by the MdTA.
Michael J. Blair, P.E., is senior associate with Johnson, Mirmiran & Thompson (JMT) in Sparks, Md. He can be contacted at mblair@jmt.com.
