This paper reviews current specifications for clearance time and acceleration and speed characteristics of Multi-combination vehicles MCVs. It reports an in-field testing program conducted to measure trajectories of a range of MCVs and a model calibrated from the tests to describe vehicle trajectory. It then examines trajectories of MCVs based on the model, compares results with current specifications, and identifies avenues of future research. An understanding has been gained from this model on the retarding influences of mass and grade on acceleration capability and attained speed. Curves estimating clearance times for crossing widths, and speed as a function of travel distance, have been established for each MCV tested, across a range of grades. The model has been used to quantify acceleration capabilities of various MCVs. It is recognised that further calibration of the trajectory model is required for estimation of trajectories over longer distances and higher speeds, and for prime movers of varying power and gearing. (a).
Abstract