The handbrake on vehicles is not only intended to secure the vehicle when parked, but must also be able to function as an emergency brake and hold the vehicle against an incline.
In modern vehicles with stability control and electric handbrakes, the emergency and incline functions are no longer as important as they once were, but roadworthiness standards still require the handbrake to provide acceptable levels of braking force.
The majority of handbrakes are selfadjusting, but if you find your handbrake is no longer as effective as it was, consider that the adjusters may be faulty or, in the case of handbrakes which have separate shoes and drums to the main wheel brakes, these may have worn out.
If the handbrake fails to hold the vehicle while parked and it rolls away, you could be held liable for damage or injury if investigation shows there were any faults with the handbrake. Consult a mechanic to ensure the handbrake is always able to do its job.
Tip courtesy of Bridgestone