For people who are blind and low vision (BLV), ridesharing provides an important means of independence and mobility. However, a common challenge relates to finding the vehicle when it arrives to an unanticipated location. Although coordinating with the driver for assistance is serviceable in the near term, new solutions are necessary when a human is no longer available in future automated vehicles. Therefore, this paper presents and evaluates a multisensory smartphone-based map system designed to enable nonvisual tracking of summoned vehicles. Results from a user study with (N=12) BLV users suggest that vibro-audio maps (VAMs) promote superior spatial confidence and reasoning compared to current nonvisual audio interfaces in ridesharing apps, while also being desirable and easy to use. A subsequent expert evaluation based on improvements suggested during the user study indicate the practical utility of VAMs to address both current and future wayfinding challenges for BLV travelers.