This is a pictograph of two adjacent roads or lanes. Such a road allows for two way traffic. Hence, Mahadevan's sign number 95 is an ideograph for the compound noun return trip.
Illustrative Text Reference:
Harappa: Tablet in bas-relief: H-1943 B: Asko Parpola, B. M. Pande, and Petteri Koskikallio, 2010: Corpus of Indus Seals and Inscriptions: Volume 3,1: Page 266: New material, untraced objects, and collections outside India and Pakistan: Suomalainen Tiedeakatemia.
Comment:
It is important to distinguish this symbol from the four shorter lines, of Mahadevan's sign number 1019, which depict four counting rods.
Image Credit:
Indus Script Sign Number 95: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.