Search Results

This paper discusses the values that Adaptive Cruise Control (ACC) systems can provide to the consumer now and in the future. It contains results from research applicable to understanding ACC behavior in traffic streams. The paper includes findings on (1) non-intrusive means for characterizing ACC behavior, (2) the influence of ACC behavior on the microscopic properties of traffic flow, and (3) prospects for the use of ACC systems to relieve driver frustration in heavy traffic as well as contributing to smoother traffic flow.

This paper describes control system and psychological concepts enabling the development of a simulation model suitable for use in emulating driver performance in situations involving the longitudinal control of the distance and headway-time to a preceding vehicle. The developed model has mathematical expressions and relationships pertaining to the driver's skill in operating the brake and accelerator (“inverse dynamics”) and the driver's perceptual and decision-making capabilities (“desired dynamics”). Simulation results for driving situations involving braking and accelerating are presented to aid in understanding the research work.

Physical prototypes of two forms of intelligent subsystems for increasing a truck driver’s ability to maintain stable operations with an articulated heavy-duty vehicle have been designed, constructed, and demonstrated. The two systems deal, respectively, with (1) quasi-steady-state rollover and (2) rearward amplification of lateral acceleration (especially in multi-articulated trailer combinations). Both forms of instability have been documented through prior research and both are known to influence the crash record. Results from testing show that both systems are viable from a technical point of view.

The results from this field operational test (FOT) show differences in the longitudinal control of headway between manual driving and driving with an adaptive cruise control (ACC) system. Based on measurements made during naturalistic driving by laypersons, it is found that the ACC mode of driver assistance contributes to longer following distances and is perceived to improve driver comfort and convenience. Observations on desirable improvements for ACC systems are presented.

The tests described here have been used to provide a preliminary checkout of the control functionality of a prototype adaptive cruise control (ACC) system being used in a field operational test of intelligent cruise control. The results presented provide an initial characterization of the headway control performance of the ACC system. The inputs to these tests are the speed of the preceding vehicle. The results of the tests are based upon measurements of range, range rate, velocity, transmission shift commands, and velocity commands resident within the ACC system. Numerical performance measures are derived from these data and used to characterize system performance quantitatively. Results from these types of tests could be used in assessing differences in headway control characteristics associated with various ACC systems.

A linear mathematical model is developed for studying the directional response and yaw stability of many-axled, multi-articulated tanker trucks. Analytical results obtained from the model provide an understanding of (1) the factors leading to unstable lateral responses of double tankers when only the rear compartment of the rear (pup) trailer is loaded and (2) the likelihood of rollover of the pup trailer in obstacle-avoidance maneuvers on the highway. Rigidizing the connection at the pintle hook is found to improve the directional performance of the double tanker.