"手制动杆" can be translated into English as "handbrake lever" or "parking brake lever".
"Handbrake lever" is a more general and commonly used term in many contexts, especially in everyday language or when referring to the lever used to engage the handbrake in vehicles.
"Parking brake lever" is a more specific term that clearly indicates the lever's purpose, which is to engage the parking brake. This term might be more commonly used in technical or automotive contexts.
Both terms are acceptable, and the choice between them may depend on the specific context or the level of formality required.