In this composite Indus sign, the verb to brake is followed by the verb to drive. Hence, Mahadevan's sign number 2311 is the adjective stop-start or stop-and-start.
Illustrative Text References:
Lothal: Seal: L-5 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 239: Collections in India: Suomalainen Tiedeakatemia.
Mohenjo-daro: Seal: M-198 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 53: Collections in India: Suomalainen Tiedeakatemia.
Image Credit:
Indus Script Sign Number 2311: List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.