Heavy vehicle driver workload assessment. Task 7B, in-cab text message system and cellular phone use by heavy vehicle drivers in a part-task driving simulator

Hanowski, Richard; Kantowitz, Barry; Tijerina, Louis · 1996 · ROSA P / United States. Joint Program Office for Intelligent Transportation Systems

archive: archived pipeline: cataloged verified

Get this paper ↗ (full text — opens at the source; we link to it, we don't host it)

Summary

This study evaluates the impact of in-cab secondary tasks on heavy vehicle driver workload and vehicle performance. Motivated by the increasing integration of Intelligent Transportation Systems (ITS) and high-technology devices in commercial vehicles, the research aims to assess the safety implications of concurrent task execution. Specifically, it examines how cellular phone use and text message display systems compete with the primary driving task. The study serves as a supplement to a prior on-the-road field study, utilizing a part-task driving simulator to provide controlled conditions for measuring object detection and lanekeeping under specific road curvatures and traffic densities. Fourteen male commercial driver license (CDL) certified truck drivers participated in the experiment using a STISIM driving simulator equipped with a Kenworth truck cab mock-up. The experimental design involved six driving scenarios varying by traffic density (high vs. low) and the presence of secondary tasks. Drivers performed three types of cellular phone dialing tasks (auto-dial, local, long-distance), two cognitive dialogue tasks (biographic questions and mental arithmetic), and seven CRT text message reading tasks (including tachometer checking, time checking, radio tuning, and multi-line reading). Performance was measured through lanekeeping metrics (mean lane position, standard deviation, lane exceedence), vehicle speed, steering wheel rate, and object detection latency for pedestrians. Results indicated that driver-vehicle performance varied significantly depending on the type of in-cab task and traffic density. CRT text message reading tasks had a more noticeable negative impact on performance than dialing or cognitive tasks. Specifically, drivers maintained a lane position closer to the center line during radio tuning, 4-line reading, and local-dialing tasks compared to time reading. Manual tasks, particularly radio tuning, resulted in lane positions significantly closer to the center line than other manual conditions. High traffic density caused drivers to keep their lane position closer to the center of the lane compared to low density conditions. The study also found that performance was differentiated by traffic density, though to a lesser extent than by task type. The findings suggest that visual-manual tasks involving text displays and radio tuning impose greater workload and degrade lanekeeping performance more than cognitive or simple dialing tasks. The study concludes that part-task simulators can effectively replicate trends observed in field studies, offering a viable alternative for assessing driver workload. These results provide a basis for establishing "good ergonomic evaluation practices" for ITS devices, highlighting the need to carefully evaluate the safety implications of in-cab technologies that demand visual and manual attention from heavy vehicle operators.

Key finding

CRT reading tasks had a relatively more noticeable impact on driver-vehicle performance than did either the dialing or cognitive tasks.

Methodology

simulator

Sample size: 14

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.

• visual manual
• mental demand
• mobile phones
• manual
• workload measurement
• traffic density

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).

• Empirical Findings: observational prevalence, behavioral performance data
• Methodological Resource: validation psychometrics