NREL/Volpe Cooperation • IVBSS and Safety Pilot data tables show total time in bins of following speed and distance - IVBSS split P&D versus line-haul shifts – focus of NREL investigation is line-haul shifts - Safety Pilot is only P&D operation, less value for “background platooning” • Volpe report is the best evaluation of driver following behavior available - Study of larger population would be valuable • Answer goes against perception that “background platooning” is prevalent - Only 2.2% of driving time >60 mph had a lead vehicle detected within 300 ft • < 0.2% background “savings” possible • Lead vehicle was at a distance greater than 130 ft for bulk of time detected • Video-validated sample, showed 57% of events were LDV not HDV - Likely much less aerodynamic savings

50 ft and 75 ft; still slight increases at 30 ft and 40 ft, but greatly 

reduced from 2014

• Independent test data show significant fuel and emissions savings

for all platooning scenarios being considered for near-term 

deployments

• In the longer term, platooning fuel savings can be enhanced by 

addressing barriers to closer platoon formation—such as reduced

engine cooling—and more vehicles in platoon

• Significant correlation was observed between multiple track studies, 

wind tunnel testing, and CFD, but there is more to learn regarding 

behavior under close formation and longer following distances

• Naturalistic study shows that existing “background platooning” is

minimal and does not significantly impact fuel savings

• Early measurements of increased NOx emissions appear to have 

been addressed through control strategy adjustments—latest data 

show decreased NOx emissions for platooned vehicles

This work was sponsored by the U.S. Department of Energy (DOE) Vehicle Technologies Office 

under the Vehicle Systems Program’s Advanced Vehicle Testing Activity. The authors wish to 

thank DOE’s Lee Slezak and David Anderson. The authors also wish to acknowledge Peloton, 

Inc.; Auburn University; the North American Council for Freight Efficiency; and DENSO’s 

Michael Bima, who produced and provided some of the data presented in this poster.

“Big data” fleet platooning opportunity analysis from highresolution fleet telematics data (planned NREL activity): • Large multi-fleet aggregate geospatial analysis • Currently looking for fleet/telematics provider partners • Define fuel savings for large fleets that adopt platooning 

technology - Geospatial analysis of current platooning opportunity - Fuel savings based on fuel rates when platooning available - % of miles platooning capable for a large fleet acting 

independently

• Estimate fuel savings potential if all applicable long-distance 

trucking fleets adopted platooning (operating independently)

• Define maximum possible fuel savings from the case in which 

all commercial highway vehicles are equipped with compatible 

platooning technology (i.e., any truck has ability to communicate 

and operate under controlled platooning, regardless of ownership)

• Define gallons saved versus adoption curve with cooperative

platooning systems - Unique relationship means greater savings with greater 

adoption—non-linear savings rate

• Define curve between individual independent fleet adoption and 

maximum possible case - Quantify the value (fuel savings) of developing competing 

systems with the ability to function together

- Identify how much assistance is needed to become selfsustaining technology - Provide scale of fuel savings possible from cooperative fleets and 

national perspectives

DENSO CFD results presented with permission from Michael Bima

NACFE testing used a different method of calculating fuel savings of lead and trailing vehicles

Photos courtesy of LLNL, NREL 38965 and 38966

Photos courtesy of LLNL, NREL 38961, 38964, and 38963

Photo courtesy of Peloton, NREL 31237

Evaluation results pertaining to 

trailing vehicle: • Significant fuel savings for the 

trailing vehicle at most distances

• Trailing vehicle trends match well 

for magnitude and slope: - Reduced savings in 30–50 ft range 

(note: net savings for both vehicles 

combined was still achieved)

- Cause of reduced savings at these 

distances is not fully understood

, g

• Wind tunnel results at less than 

30 ft following distance show 

likely trend departure, though

limited road/track data exists for 

comparison

Evaluation results pertaining to 

lead vehicle: • Larger fuel savings at distances 

less than 50 ft, with very modest 

savings at longer distances

• Lead vehicle trends match well for 

following distance at knee in the 

curve (50–60 ft) as well as slope 

before and after the knee

KEY TAKEAWAYS

ACKNOWLEDGMENTS

This presentation does not contain any proprietary, confidential, or otherwise restricted information

-20% 

-15% 

-10% 

-5% 

0% 

5% 

10% 

15% 

20% 

25% 

30% 

20' 30' 40' 50' 75' 150' 

Increase Over Baseline 

Distance Behind Lead Vehicle 

SCR Inlet NOx (g/bhp-hr) 

NOx Corrected for Temperature and Humidity 

-30% 

-20% 

-10% 

0% 

10% 

20% 

20' 30' 40' 50' 75' 150' 

Increase Over Baseline 

Distance Behind Lead Vehicle 

SCR Inlet Total NOx (g) 

Corrected for Temperature and Humidity 

2015 Trailing Vehicle 

2014 Trailing Vehicle 

2015 Trailing Vehicle 

2014 Trailing Vehicle 

0.0 

0.5 

1.0 

1.5 

2.0 

2.5 

20' 30' 40' 50' 75' 150' 

Dither Rate (Average Change 

 in % Torque/0.2 seconds) 

Distance Behind Lead Vehicle 

Dither Rate 

(Average Delta % Torque/0.2 s) 

Pressure Probe

Lead Vehicle

Trailing Vehicle

Configurations for SAE Procedures