About Green Light Lincoln (GL2)
“Green Light Lincoln” is an initiative being undertaken by the City of Lincoln Traffic Engineering Division to improve traffic flow and traffic safety city wide. The focus of the effort is improvement of the overall traffic management system. Through prioritization and implementation of several key components of the Traffic Management Master Plan the impact of this initiative will be realized by motorists in every corner of the community.
GL2 will require many upgrades to our existing system and equipment. Some will need complete replacement. Key components include:
New Signal System Management Software and Hardware
The City’s current traffic management software was installed in 1999. As of 2011 the developer no longer offers software support. The program can only run on a Windows XP computer, which is also no longer supported.
New Intersection Detection Systems
The majority of traffic signals have equipment (“detectors”) that tells a computer when traffic arrives at the intersection, so that traffic can be given a green light. Detecting arriving vehicles can be achieved in a variety of ways, but some are more reliable than others. Some previous practices are not necessarily the most cost effective or reliable means of providing detection over the life of the traffic signal. The current standard detection practice in the city is using inductive loops. Inductive loops require a ‘coil’ of wire to be placed in a sawcut or under the concrete. When a vehicle enters the magnetic field of the loop, it places a “call” into the computer telling the intersection that a car is present. Potholes, pavement damage and even seasonal changes where the concrete or asphalt contract and expand can cause the loop wires to be broken. When the coil of wire is cut or broken, it tells the computer that there is always a vehicle present even if it is not. This results in the intersection calling up the green or holding it too long for no reason.
The City has begun using more advanced technology in replacing these inductive loops, using cameras and radar detection equipment, along with placing all inductive loops under newly poured concrete and no longer allowing them to be sawcut into the concrete.
New Signal Displays and Signal Phasing Alternatives
The City will reevaluate the use and installation of protected left turn movements, and when those movements will be served to better accommodate flow for oncoming traffic. Cycle lengths (the time from the start of green on your street until your green starts again) will be evaluated to better clear the left turn movements. Flashing Yellow Arrows, which are becoming the new nationwide standard, will be used more frequently.
Intelligent Transportation Systems (ITS) Deployment
ITS equipment is extremely helpful for making adjustments to the signal system. Installing more Pan-Tilt-Zoom (PTZ) cameras, Bluetooth devices, Wi-Fi devices, and Dynamic Message Signs (DMS) lend support to making quicker and more efficient changes to the system as traffic conditions warrant.
Corridor Signal Optimization (re-timing) Program
Every signalized intersection will be reevaluated for proper timing. The starting focus will be to improve timing along major corridors to minimize stop and go traffic along arterial streets.
Multiple phases are planned for Green Light Lincoln. Phase 1, which was completed in December 2017, included improving traffic signal timings along the following corridors:
- Nebraska Highway 2 (Van Dorn Street to S. 91st Street)
- N. 84th Street (Cornhusker Hwy to “O” Street)
- S. 84th Street (“O” Street to Nebraska Hwy 2)
- S. 70th Street (“O” Street to Pine Lake Road)
- “O” Street (25th Street to Skyway Road)
- Vine Street (N. 14th Street to N. 70th Street)
- Capitol Parkway/Normal Boulevard (Antelope Valley Parkway to S. 56th Street)
- Antelope Valley Parkway (Military Road to “K” Street)
- Cornhusker Highway (N. 11st Street to L-55X)
Traffic Monitoring and Incident Management Capability Improvements
The city is constructing a new Operation Center to better facilitate this new technology and provide quicker and more efficient responses to various incidents throughout the city.
The continued deployment of Green Light Lincoln will result in vast improvements to the overall traffic signal system, and numerous projects with high benefit/cost ratios. Key benefits of this initiative are wide-reaching and include:
- Reduce travel times, delays and stops
- Reduce vehicle emissions and pollutants
- Reduce fuel consumption for savings at the pump
- Reduce the number and severity of crashes
- Smooth traffic flow and reduce driver frustration
- Delay the need for major street widening projects
Frequently Asked Questions
- When did this project start?
GL2 kicked off January 1, 2016. Phase 1 implementation began in October 2016 and concluded in December 2017. Phase II implementation is now underway.
- When will I see any improvements?
It all depends on the route you drive. Improvements will be made city wide. Over 120 intersections are planned for improvement in 2017-2018.
- Why can’t we flash the lights at night like Omaha or other cities?
As it currently stands, Lincoln does not implement late night (off peak) flashing schedules for the signals. The industry has leaned away from this in years past, based upon recommendations from Federal Highway Administration (FHWA) regarding safety concerns. It comes down to a benefit/cost issue. There are certainly select intersection locations that could likely benefit from some off-peak flashing implementation. We are going to be re-evaluating this procedure as part of the upcoming Signal Optimization Project efforts where we will be updating signal timing settings as part of formal corridor-wide traffic signal timing with consultant support contracts. The bottom line is there will be many updates, but they will be data driven, and based upon best practices, and latest industry standards. If we formally move forward with changes such as flashing schedules, there will need to be public stakeholder outreach and further education.
- Will you adjust the signal timing during road construction projects?
With the use of the new ITS devices, we will be better equipped to monitor and make any needed adjustments to the signal timing. Being able to control the signals from the new Operations Center will make many different adjustments possible.
- Why are we changing to flashing yellow arrows?
These signals are being introduced nationwide and ultimately will be required at all intersections where there is a separate left-turn arrow signal. This change is the result of a national study conducted by the Federal Highway Administration which demonstrated that the flashing yellow arrow helps prevent crashes, moves traffic through an intersection more efficiently, and provides more flexibility in traffic management.
- Why don’t all the pedestrian lights count down?
Lighting the pedestrian Walk and countdown Flashing Don't Walk signals every time has impacts on the ability to move traffic through an intersection. Depending on the width of the intersection and the number of pedestrians that cross, lights must typically stay on longer when the pedestrian signals are in use. By installing pedestrian pushbuttons and not bringing up the Walk and the Flashing Don’t Walk every time, we can more efficiently give the green time to the majority of the traffic and still serve pedestrian crossing needs when they are present.
- Are lights timed with other lights on intersecting corridors so a driver turning off one road does not immediately get stopped at a nearby red light on the other road?
It depends on the situation and traffic volumes. Most times we set coordination plans for the mainline or through movements on each street. When both streets are coordinated, turning onto a new street puts you in the non-coordinated portion of that street. You would typically get a red light at the next signal, but would then be back in coordination when it turns green. At certain locations where there are very high left or right turn volumes off a side street, we will time cross-street signals to account for that.
- Are the detection cameras used for automated enforcement?
Automated enforcement is not allowed under Nebraska law and the cameras being employed for traffic detection do not have this capability. They can identify vehicles of various sizes and pedestrians, but do not monitor red lights or speeding. The cameras are also not regularly recorded, so the City cannot provide video as evidence when crashes occur.
Lonnie Burklund, Project Engineer
City of Lincoln, Traffic Engineering
Mark Lutjeharms, Sr. Engineer
City of Lincoln, Traffic Engineering
David Young, Fiber Infrastructure & ROW Manager
City of Lincoln
Benjamin Cosier, Project Manager
City of Lincoln, Traffic Engineering
It’s GO Time!