Track-Based Aerodynamic Testing of a Two-Truck Platoon
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Bibliographic record
Abstract
<div class="section abstract"><div class="htmlview paragraph">Fuel savings from truck platooning are generally attributed to an aerodynamic drag-reduction phenomena associated with close-proximity driving. The current paper is the third in a series of papers documenting track testing of a two-truck platoon with a Cooperative Adaptive Cruise Control (CACC) system where fuel savings and aerodynamics measurements were performed simultaneously. Constant-speed road-load measurements from instrumented driveshafts and on-board wind anemometry were combined with vehicle measurements to calculate the aerodynamic drag-area of the vehicles.</div><div class="htmlview paragraph">The drag-area results are presented for each vehicle in the two-truck platoon, and the corresponding drag-area reductions are shown for a variety of conditions: gap separation distances (9 m to 87 m), lateral offsets (up to 1.3 m), dry-van and flatbed trailers, and in the presence of surrounding traffic. For the standard aligned platoon, the results demonstrate up to 8% drag reduction for the lead vehicle, with drag reductions exceeding 20% for the trailing vehicle at some yaw angles. Wind-velocity measurements on the following truck suggest that the drag-area reductions are due to a combined effect of reduced apparent wind speed and reduced effective yaw angle in the wake of the lead truck. In the presence of a three-vehicle traffic pattern forward of a single truck, drag-area reductions on the order of 10% were observed relative to the same truck travelling in isolation. When platooning with this surrounding-traffic pattern, the trends and magnitudes of aerodynamic drag reduction are shown to be retained, relative to the platoon in the absence of other traffic, corroborating observed trends in of fuel-savings performed simultaneously.</div><div class="htmlview paragraph">As a supplement to the current study, a first-of-its-kind coast-down test was undertaken with the two-truck platoon where the CACC system was used to maintain a constant distance between the vehicles during each coast. The CACC system was used on the following vehicle when the lead vehicle was coasting and on the lead vehicle when the follower was coasting. Despite some scatter in the data from this proof-of-concept study, the results are consistent with those of the principal constant-speed measurement technique of this paper. This preliminary study demonstrates that the coast-down test method, which previously was only applied for single vehicles, is also applicable to vehicle platoons.</div></div>
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it