辆

Left vehicle radical - simplified 4-stroke form of 車 (Kangxi #159), originally a pictograph of a chariot or cart seen from above. The indexing radical of 辆. Carries the literal meaning: 辆 is a measure word for vehicles - one car, one bus, one truck. Same radical anchors 轮 (wheel), 转 (turn), 输 (transport), 较 (compare via two carts).

Right component supplies the sound (两 liǎng → liàng, just a tone shift) and a strong semantic echo: 两 originally pictured a yoke holding two horses to pull a cart. That makes 辆 etymologically transparent: a yoked-pair drawing a vehicle = one full cart. The yoke origin of 两 explains why this measure word and 两 'two' share the same character.