Three major factors combine to determine a vehicle’s fuel consumption and emissions:

• The design and capabilities of the powertrain system and vehicle itself (e.g., diesel, hybrid, aerodynamic profile, etc.)

• The type and quality of the fuel used (e.g., low-sulfur, synthetic, biofuel)

• The operation and handling of the vehicle (e.g., speed, stop-and-go traffic, idling, etc.)

Even if the first two are constant, improvements in the third can provide some non-trivial savings. (Or, on the flip side, can result in fuel consumption and emissions higher than the design point of the vehicle.)

Nikkei News reports that major Japanese trucking companies are introducing Global Positioning System (GPS) devices in their fleets to measure emissions accurately and to optimize truck routes, with the goal of reducing CO₂ emissions.

• Nippon Express has installed such systems in all of its 17,500 trucks at a cost of ¥2.5 billion ($23.8 million, or $1,360 per truck). The trucking firm estimates that using the new system will help slash CO₂ emissions by nearly 10%, and plans to use it in another 10,000 trucks owned by group companies.

• Hitachi Transport System and its group firms will introduce similar systems  by next spring in all 250 trucks operating in the greater Osaka area. The costs, including those for software development, are estimated at ¥400 million ($3.8 million, or $15,200 per truck).

  Hitachi Transport (which began introducing hybrid trucks in 2004) operates its truck transport service on a regular time schedule on more or less fixed routes in the Osaka area, which the company believes makes it easier to monitor the results of its emission-reduction initiative. The group also aims to have its subcontractors use the GPS system for their 750 trucks within two years.

• Meiji Dairies Corp. will rely on GPS systems to keep tabs on 1,300 trucks, or just under 70% of the fleet it and its business partners operate, with a view to reducing carbon dioxide emissions by 2% within two to three years, according to the company.

Transport accounts for 20% of Japan’s total CO₂ emissions. The sector’s emissions are increasing—the amount emitted in fiscal 2003 was nearly 20% higher than the fiscal 1990 level.

The government is targeting a five percentage-point reduction of transport sector emissions by 2010 to a level 15% higher than in fiscal 1990. The government is requiring transport companies and their clients to submit their reduction plans and also report on their progress.

Automakers and researchers have been working with the notion of using a GPS system and telematics in general in transport fleets in a variety of applications to reduce fuel consumption and emissions for a number of years.

DaimlerChrysler researchers, for example, began working with an experimental cruise control system in 2002. The result is “Predictive Cruise Control” (PCC), a cruise control system that not only maintains a preset speed, but also regulates the engine by assessing driving conditions ahead (via GPS) and adjusting speed accordingly, delivering significant fuel savings.

At the beginning of an upgrade, for example, a conventional cruise control system would try to compensate for the truck’s deceleration by boosting engine output to the maximum. Then, on the downgrade the system would have to shift down drastically to prevent the truck from rolling too fast.

PCC instead makes optimum use of the truck’s kinetic energy by allowing it to build up momentum before the hill and then, at the top, gearing down even further in anticipation of the truck’s rapid acceleration as it moves downhill. The PCC computer can do all this because it has been fed the topographical data for the route and, thanks to the GPS navigation system, also knows the truck’s precise position.

There have been numerous research projects related to estimating and analyzing vehicle emissions based on driving activity The plot to the right is from some work done by GeoStats in developing methodologies being used to study the impacts of trip-level activity patterns on sub-trip level emissions rates and total emissions per trip and household.

As another example, Sensors, Inc. offers communications and GPS modules for its SEMTECH measurement systems that can report on NO, NO₂, CO, CO₂ and THC. Data can be provided over cellular or internet links in addition to on-board collection and storage. Location and gradient can also be provided as part of the data file for further processing and analysis.

Initial tests confirmed the estimates: depending on the specific route, PCC can deliver fuel savings of 2% or more.

The city of San Diego, California has already implemented GPS technology to optimize the routes of more than 100 refuse trucks. That, combined with using LNG derived from landfill methane gas, has cut some 3,000 tons of CO₂ each year (300 tons per year per truck— an average car in the US generates approximately 7 tons per year). The size of the reduction is due more to the LNG than the GPS, I’m sure, but every contribution helps.