Display formats and commercial vehicle operator (CVO) workload

Carney, Cher; Dingus, Thomas A; Hankey, Jonathan M; Mollenhauer, Michael A; Neale, Vicki L · 1997 · ROSA P / United States. Federal Highway Administration

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Summary

This study, conducted by the Federal Highway Administration, investigates the impact of Advanced Traveler Information Systems (ATIS) on the workload and driving performance of Commercial Vehicle Operators (CVOs). The research was motivated by the increasing integration of Intelligent Transportation Systems into commercial vehicles and the need to determine if interacting with these systems while driving compromises safety. Specifically, the study aimed to identify the threshold at which ATIS task demand degrades driving performance to unsafe levels and to evaluate how display modality, interaction level, and information volume affect driver workload. The researchers employed a within-subjects experimental design using the Iowa Driving Simulator. Two distinct groups of ten drivers each were tested: over-the-road truck drivers, who are formally trained and operate complex equipment, and taxi drivers, who typically lack formal training and operate passenger vehicles. The independent variables were the sensory mode of display (visual-only versus combination visual and auditory) and ATIS task difficulty, categorized into baseline, low, medium, high, and super-high levels. Task difficulty varied by the number of required interactions and the amount of visual information presented. Dependent variables included objective driving performance measures (steering variability, speed variability, lane deviations), eye glance behavior, system operation errors, and subjective workload assessments. The results revealed distinct patterns for the two driver groups. Truck drivers demonstrated effective self-regulation, maintaining safe driving performance until task demands reached the "super high" level, which required a high number of interactions. For truck drivers, the number of control activations had a greater impact on workload than the amount of information displayed; doubling the information between medium and high tasks did not significantly alter performance. Conversely, taxi drivers showed a significant increase in workload and degraded driving performance (increased steering and lane variability) when moving from low to medium task levels, which introduced manual interaction via steering wheel buttons. Notably, adding auditory cues to the visual display provided no significant benefit for truck drivers but reduced lane deviations for taxi drivers. The study concludes that interaction complexity, rather than information volume, is the primary driver of increased workload. Based on these findings, specific design guidelines were established. For truck drivers, systems should minimize control manipulations to fewer than four, as redundant auditory cues offer no advantage. For taxi drivers and those with minimal training, interaction should be minimized, particularly for time-dependent tasks, and systems should prioritize navigation and communication information. The research underscores that while experienced drivers can manage higher cognitive loads, any interaction with ATIS increases workload, necessitating careful design to prevent safety degradation.

Key finding

For truck drivers, driving performance degradation occurred only at the highest task difficulty levels, indicating that the number of manual interactions affects workload more than the amount of information presented, while for taxi drivers, adding auditory cues to visual displays significantly reduced lane deviations.

Methodology

simulator

Sample size: 20

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via bulk_ingest_rosap on 2026-05-23 (6 acquisition events logged).

Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

Topics

Ranked by relevance to this paper. Hover a topic for its definition.

• mental demand
• road complexity
• workload measurement
• feedback modes
• temporal
• hud ar windshield

Information type

What kind of knowledge this paper contributes, grouped by family — independent of topic (what it is about) and method (how it was studied).

• Applied Guidance: design guidelines
• Empirical Findings: behavioral performance data
• Theoretical Contribution: theory or model