The routing protocol in connected vehicles (CVs) is vulnerable to wormhole attacks where attackers can deceive legitimate nodes and purport them as if they are immediate or close neighbors. The Ad hoc On-Demand Distance Vector (AODV) protocol is a routing packet protocol designed for mobile nodes. However, AODV may not have been explicitly developed with security issues, specifically wormhole attacks, in mind, thereby requiring a detection algorithm to secure route establishment. This paper introduces the Wormhole-Protocol-Detector ( WPD ), a lightweight protocol for detecting and mitigating wormhole attacks. WPD is designed to work on a highway that is clustered into equal segments and equipped with road side units (RSUs) in predefined locations to monitor each segment. WPD consists of three phases: monitoring and detection of out-of-range packets, estimating the hop count between source and destination nodes, and identification of nodes participating in a wormhole connection. Together, these phases enable legitimate nodes to avoid the wormhole link and obtain secure routing paths between CVs. To validate our approach, we apply WPD to a CVs simulation where different types and lengths of wormhole, including a new wormhole attack method, can be applied to the CV network. Our experimental results suggest that WPD can detect wormhole attacks with a high detection rate and minimum false positives.