A two-truck platoon based on a prototype cooperative adaptive cruise control
(CACC) system was tested on a closed test track in a variety of realistic
traffic and transient operating scenarios - conditions that truck platoons are
likely to face on real highways. The fuel consumption for both trucks in the
platoon was measured using the SAE J1321 gravimetric procedure as well as
calibrated J1939 instantaneous fuel rate, serving as proxies to evaluate the
impact of aerodynamic drag reduction under constant-speed conditions. These
measurements demonstrate the effects of: the presence of a
multiple-passenger-vehicle pattern ahead of and adjacent to the platoon, cut-in
and cut-out manoeuvres by other vehicles, transient traffic, the use of
mismatched platooned vehicles (van trailer mixed with flatbed trailer), and the
platoon following another truck with adaptive cruise control (ACC). These
scenarios are intended to address the possibility of “background aerodynamic
platooning” impacting realized savings on public roads. Using calibrated J1939
fuel rate analysis, fuel savings for curved track sections versus straight track
sections were also evaluated for these scenarios, highlighting differences in
the implementation of the CACC control strategies compared to a stock ACC
implementation. The use of different trailer types and the presence of
passenger-vehicle traffic patterns showed a measurable impact on platoon
performance in some conditions, but the basic fuel savings trends were
retained.
