Impact of speed limit strategies on the coupling between drivers' approaching and lane-changing behavior in work zones considering human heterogeneity.

Objectives

Speeding while approaching highway work zones reduces the time available for drivers to identify hazards, adjust speed, and prepare for lane changes. However, the extent to which alternative speed-limit configurations affect approach and lane-changing behaviors, the coordination between these behavioral domains, and response heterogeneity across driver groups remains insufficiently quantified. This study compared driver responses across five speed-limit schemes.

Methods

A driving-simulator experiment was conducted to collect behavioral data from 37 licensed drivers. Approach behavior was characterized by average approach speed and maximum deceleration, whereas lane-changing behavior was characterized by lane-change decision distance and minimum conflict distance. A coupling coordination degree model was used to quantify the relative coordination between the two behavioral domains. Generalized estimating equations (GEE) were used to examine the main effects of speed-limit scheme, gender, and professional driving status, as well as the interactions of speed-limit scheme with gender and professional driving status, on the four behavioral measures.

Results

Average approach speed, maximum deceleration, lane-change decision distance, and minimum conflict distance differed significantly across speed-limit schemes, with the relative rankings of the five schemes varying among the four behavioral measures. The 300-m graded scheme was associated with a lower approach speed, earlier lane-change initiation, and a larger post-lane-change spatial margin and yielded the highest coupling coordination degree (0.995). The GEE models identified significant speed-limit scheme × gender and speed-limit scheme × professional driving status interactions for all four behavioral measures. Female drivers generally approached at higher speeds than male drivers but initiated lane changes earlier and maintained larger post-lane-change spatial margins. The effects of professional driving status varied across speed-limit schemes; under the non-graded schemes, drivers without professional driving experience exhibited stronger braking responses and later lane-change initiation.

Conclusions

The proposed framework integrates the relative coordination between approach and lane-changing behaviors with heterogeneity in driver responses, providing a quantitative reference for the comparative evaluation of work-zone speed-limit schemes and the subsequent design and validation of behavior-responsive speed-management measures.