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Risk-Based Freeway Merging And Lane-Changing Decisions For Autonomous Vehicles, Weimin Jin

All Dissertations

The safe freeway merging and lane-changing operation for fully Autonomous Vehicles (AVs) in mixed traffic (i.e., the presence of AVs and non-AVs in the traffic stream) is a challenging task. The AV merging and lane-changing operation could increase crash risks and reduce operational efficiency significantly in mixed traffic.

This dissertation quantifies the freeway merging crash risk and develops a freeway merging decision strategy based on crash risk assessment for an AV attempting to merge in the target lane with non-AVs. The performance of the risk-based merging decision strategy is evaluated in uncongested, near-congested, and congested traffic conditions. The analyses show …

Shining Light On Retroreflectivity: Perceived Brightness Of Surfaces With Varying Reflective Properties, Savana King

All Theses

Typical road users appear not to understand retroreflectivity despite nightly exposure to retroreflective materials such as road signs. While retroreflective surfaces have been engineered to reflect light back in the direction of its source, retroreflectors appear to be diffuse reflectors in most viewing conditions. This may lead road users to underestimate its value in nighttime roadway applications and contribute to vulnerable road users’ under-use of retroreflective markings to enhance their own conspicuity at night. In this context, a critical benefit of retroreflective materials is a robustness to changes in entrance angle, the angle at which the light strikes the material.This …