Automated vehicles are an emerging technology in which consumers have low levels of trust. Researchers and designers can understand and improve consumer trust through research but doing so effectively requires the reliable measurement of trust. Although general trust-in-automation measures exist, a psychometrically well-developed measure specific to self-driving vehicles would be a substantial improvement. The purpose of this dissertation was to address that need. Candidate items were created after a thorough literature review and then refined through expert feedback in two steps. Preliminary item groups were identified via an open card sort; the resulting relationship between items and groups were used to initially refine the item pool. A closed sort was then conducted to follow up on the results from the first study and further refine the item pool. Based on the results of the closed sort, a final item pool was generated by rewording items and generating content for facets of trust that were identified as having too few items. This final group of items were given to 400 participants who rated their trust in riding in a self-driving vehicle, as portrayed in a narrative. The Trust in Self-driving Vehicles Scale (TSDV) was created by analyzing participants’ responses via psychometric methods. Four reliable and interpretable factors were extracted from participants’ responses. Five items were retained for each factor to create the TSDV. The validity of the instrument is evidenced by the TSDV’s ability to discriminate between a trustworthy and non-trustworthy vehicle, as portrayed in scenarios in the scale development sample, a replication sample, and a video-based validity study. Application of the TSDV was demonstrated by comparing how presentation modalities (VR headset versus computer monitor) may affect trust ratings. Additionally, the TSDV was used in an exploratory vignette study to evaluate how knowledge that a cyberattack was carried out on an AV impacts users’ trust in the vehicle. Future directions and applications of the TSDV are discussed.