Faster? Shorter? Try Cheaper, Greener: Program Gives Drivers the Most Fuel-Efficient Route

By Tracy Cozzens

Most GPS devices in cars today give the driver two choices: shortest route or fastest route. GreenGPS provides a third option: most fuel-efficient route.

With gas prices skyrocketing, many drivers would be happy to spend a few more minutes on the road, or take a different route, if it meant burning less gas.

The answer could be the GreenGPS navigation service, now being developed by researchers at the University of Illinois at Urbana Champaign (UIUC), which finds the most fuel-efficient route for your vehicle.

“The most fuel-efficient route may be different from the shortest route because the latter may pass through downtown stop-and-go traffic,” explained Tarek Abdelzaher, project lead and computer science professor. “It may also be different from the fastest route because vehicles are not as fuel efficient at higher speeds.”

All cars manufactured in the U.S. since 1996 come with a standard interface to their internal gauges and engine measurements called the On-Board Diagnostics Interface, or OBD-II. GreenGPS runs on the driver’s GPS-enabled cell phone and uses an off-the-shelf wireless adaptor plugged into the vehicle’s OBD-II port to receive engine readings via Bluetooth.

The cell phone collects the readings and connects to a server that models the engine’s fuel efficiency and customizes navigation advice to the particular vehicle, Abdelzaher explained.

The best route computed by GreenGPS to the same destination may differ from one vehicle to another. “For example, my vehicle uses about 20-25 percent more gas in stop-and-go traffic compared to free-flowing traffic, whereas my wife’s car uses closer to 40 percent more,” Abdelzaher said. “GreenGPS may recommend to her a path that is longer but has no traffic, whereas it might recommend to me a path that incurs some traffic but is shorter.”

To users, GreenGPS looks like a regular navigation service. The driver specifies a destination, then ask the service to find a route. “It runs on your cell phone, except that in addition to the fastest and shortest route options, it offers the ‘least-fuel route’ option,” Abdelzaher said. “If the driver chooses that option, they receive the GreenGPS-recommended fuel-efficient route.”

The program works best with a small hardware addition to collect readings specific to the vehicle. “In order for the advice to be customized to the performance of your specific vehicle, the driver should invest in buying the OBD-II adaptor. It costs about $50 and is a one-time investment,” Abdelzaher said.

“If the driver does not wish to buy the adaptor, they can still use GreenGPS and supply the make, model, and year of their vehicle. In this case, GreenGPS will use data from other vehicles of the same make, model, and year, or vehicles as close to them as possible to compute the navigation advice,” Abdelzaher said. This social networking component is also being developed as part of the project.

The system pulls the GPS data from the driver’s cellphone. “If you use a GPS phone (and most smartphones have GPS), the system simply finds out your current location from your phone. Otherwise, you would need to supply both source and destination addresses (like you would when you get directions from Google Maps) and the system will show you the route on a map.”

Gas-Saving Pilots. In the first stage of testing, the team solicited volunteers to drive in the area of their university, in Urbana-Champaign, a city of 170,000. In all, 1,000 miles were driven by 16 different cars. Results demonstrated that following the fuel-efficient route saves on average 6 percent over the shortest route, and 13 percent over the fastest. “This was done on flat terrain and in the absence of significant congestion,” Abdelzaher said. “We expect that testing in higher traffic and richer topology will increase the variability in fuel consumption among different routes, resulting in even more potential savings when following the most fuel-efficient route. Verifying this conjecture is currently a topic of investigation for our ongoing research project.”

Abdelzaher said his team has just started the second stage. “In the second stage of testing, we will deploy GreenGPS on the UIUC Facilities and Services fleet (about 100 cars) and monitor performance over a longer period of time. Preparations for this deployment are currently under way. We also expect to offer GreenGPS publicly to any other volunteers who wish to help with testing.”

Impressed by early findings of gas savings, the second phase is being funded in part by a $300,000 grant from the National Science Foundation. Abdelzaher and Robin Kravets, another UIUC computer science faculty member, were awarded the grant this spring. It will help deploy GreenGPS among the campus fleet cars, and track and analyze the results.

“By sharing data on speed, fuel efficiency, and location of vehicles, better real-time navigation services can be developed that guide drivers to routes that are maximally fuel-efficient for their cars, hence reducing transportation carbon footprint,” the grant reads. “This project helps usher in a new era of sensing applications with more integration of humans, networks, and the physical world, which may have a significant impact on the economy, energy, and the environment by reducing transportation energy cost and carbon footprint.”

Other grant providers are the Office of Naval Research, which is funding research on the technology’s networking component, and IBM through its Smarter Planet initiative. As a part of this project, 200 or more cars in the Urbana-Champaign area of various makes and models will be fitted with GreenGPS. Through a social network of drivers, data and routes collected can be shared and used by those who don’t have the OBM-II adaptor installed.

Fuel consumptions for the various roundtrips between different landmarks.

The landmarks and corresponding shortest and fastest routes.