Eco-Lane and Speed Harmonization simulation results in up to 6.3 percent reduction in fuel consumption and 4.6 percent reduction in CO2 emissions.

Simulation on I-66 in Northern Virginia

Date Posted

Eco-Lanes Applications: Preliminary Testing and Evaluation

Summary Information

This paper explores the concept of Eco-Lanes along with several other concepts, in particular eco-speed harmonization applications. In an eco-lane, drivers would be required to operate their vehicles at a recommended or variable speed limit that is focused on reducing transportation energy consumption and improve mobility. The paper also looks at predicted and dynamic eco-lanes that can be opened at varying times by a Traffic Management Center (TMC), 15 or 30 minutes before the traffic begins based on historical data. The speed harmonization algorithm (SPD-HARM) had an objective of dynamically adjusting and coordinating maximum appropriate vehicle speeds in response to downstream congestion, incidents, and weather conditions to maximize throughput and reduce emissions and fuel consumption. The speed harmonization application was studied for all traffic in all lanes, as opposed to the eco-lanes scenarios that were focused only in one lane. The study demonstrated that an eco-lane system and speed harmonization can significantly reduce fuel consumption, travel time, delay, while improving air quality.


This simulation study was conducted on a heavily congested 15 mile section of Interstate 66 eastbound in Northern Virginia. The simulation was constructed using traffic data from the a.m. peak period May 1 to May 3, 2012. With this simulation several scenarios were run. First, the eco-lanes application was modeled for the entire period (6:00 a.m. to 9:00 a.m.) with drivers in the eco-lanes required to drive with mild acceleration levels. For this case, drivers could only use up to 50 percent of the maximum throttle level and 5.6 percent of vehicles were permitted to use the eco-lane. The next scenario looked at predictive eco-lanes, where the TMC is predicting severe congestion to begin at 6:30 a.m. Two cases were looked at; if the eco-lane was opened 15 minutes or 30 minutes before the severe congestion began. The 15 minute prediction case had 6.1 percent of vehicles use the eco-lanes and the 30 minute case had 6.5 percent of vehicles using the eco-lane. The last case was using the speed harmonization applications. For this case all drivers received speed recommendations.

  • The eco-lane application by itself showed reduction in fuel consumption, HC, CO, and CO2 emissions by 4.5%, 3.1%, 3.4%, and 4.6%, respectively, compared to the base case scenario.
  • For predictive eco-lanes the 15 minute case showed reductions in travel time, delay, fuel consumption, HC, CO, and CO2 emissions by 8.6%, 23.0%, 4.7%, 3.4%, 3.7%, and 4.8%, respectively, compared to the base case scenario.
  • The 30 minute predictive case showed reductions in travel time, delay, fuel consumption, HC, CO, and CO2 emissions by 10.7%, 28.7%, 5.3%, 3.4%, 3.7%, and 5.4%, respectively, compared with the base case scenario.
  • The SPD-HARM case showed reductions in total delay, fuel consumption, HC, CO, NOx, and CO2 emissions by 7.6%, 6.3%, 23.9%, 26.1%, 17.2%, and 4.4%, respectively, compared with the base case scenario.
It is noted that the savings of HC, CO, and NOx emissions for SPD-HARM operation are relatively greater than the typical emission reductions of the Eco-Lanes system. The low emission results of the SPD-HARM system are triggered by the relatively low average speeds of SPD-HARM vehicles compared with the Eco-Lanes applications.
Deployment Locations