Lessons from INDOT’s Leadership on Positive Work Zone Protection
By Mary Lou Jay
Closing off work lanes in construction zones with concrete barriers is best practice for protecting the people working on our roads, but such closures can inconvenience drivers. The loss of a lane or two at peak travel hours can make commuters late to work, delay childcare pickups and wreak havoc with people’s schedules.
To relieve the stress on both motorists and workers, the Indiana Department of Transportation (INDOT) has implemented a positive work zone protection solution, a moveable concrete barrier system that enables road contractors to keep major commuting arteries open during rush hours. With the advanced movable barrier technology, INDOT can quickly move concrete walls within a relatively short amount of time, opening travel lanes as needed, and keep traffic moving freely.
The Road Zipper ® system, from Lindsay, includes one-meter sections of highly reinforced concrete barriers and a transfer machine that can relocate the barriers from one spot to the next. The barrier-transfer machine picks up the barrier sections from one location and then its internal conveyor system transfers them to an opening on the other side of the machine where they are placed in their new position.
While INDOT has, in the past, used Road Zipper in rural areas, the system has been particularly helpful for urban area projects.
“We may need the extra lanes during the work week’s peak hours, but we may not need the same number of lanes at night or on weekends. So we can move that wall to allow more work activity to be done on nights and weekends without creating extra congestion,” said INDOT’s Senior Director of Engineering and Research, Jim Poturalski. “It gives us a lot more flexibility than having a permanent type of wall that’s there 24/7 for several weeks at a time, which would disrupt the weekday traffic needs.”
Maintaining peak traffic flow
INDOT’s first major deployment of the technology came in 2008-2009, when it helped alleviate traffic backups on I-70 coming into downtown Indianapolis from the east side. “We used it to separate traffic in two directions where we had a morning peak with everyone coming downtown and the afternoon peak when everyone was departing. We were able to allow that extra lane in the peak, depending on time of day,” said Poturalski.
Since that time, INDOT has used the movable barrier technology on many other construction jobs, usually those that involve road repairs, patch work and shoulder widening. However, there are some narrower roadways where the movable barrier technology does not work well. The system requires an ample amount of space to park the transfer machine.
INDOT uses movable barrier technology on interstate projects, because there are no intersections that require making a break in the concrete walls, stated Poturalski. These highways, which consist of three or more travel lanes that extend four to six miles in each direction, typically require several months of work. As a result, this spreads out the cost of the barrier-transfer machine rental.
There are instances when this type of technology makes sense for smaller jobs as well. In 2020, INDOT deployed the work zone protection in Indianapolis to keep travel lanes available during peak hours for a half-mile construction project on the Keystone Bridge and I-65.
“In the right application, when you have projects that you need a concrete wall to protect the work zone, the fact that you can move it in and out daily with this equipment is really a powerful business case for leveraging that technology,” Poturalski added.
Providing positive work zone protection
2021 was a dangerous year for motorists across the U.S. with traffic deaths hitting a 16-year high. However, despite Indiana’s 7.5% increase in traffic fatalities from 2020 to 2021, the number of work zone crashes during that same period remained about the same. (INDOT’s goal is to reduce that number to zero.)
INDOT is committed to using positive work zone protection, like Road Zipper, to help keep work zone accidents to a minimum. The agency chooses the positive protection solutions it uses carefully. For example, before deploying Road Zipper, they tested the system’s temporary concrete barrier walls to ensure that they met all crashworthiness requirements.
Today, INDOT has a standard specification that allows for the use of a temporary movable traffic barrier. “It becomes a pay item within the contract. It is up to the contractor to procure the specific solution of the moveable wall, but we would dictate that we want that temporary traffic barrier on specific projects,” said Jeremy Hunter, Chief Engineer of Design at INDOT.
The department plans to require movable barrier technology even more often over the next several years.
“Having the ability to restore active travel lanes when there’s no active construction certainly has a benefit to the motoring public, limiting congestion,” said Hunter, “That’s always been INDOT’s goal.”
This is Part Two in an ongoing series on Positive Work Zone Protection. In Part 1, we explored the benefits and challenges to wider implementation of positive work zone protection technologies.
