I believe the park brake will only engage up to like 6mph. Those of us with the manual brake can use it as it is foot operated cabled to the rear brake. The downshift using engine compression to get you slowed down is the first step getting to rougher road like shoulder also will slow you and if there is a turnoffs with uphill angles go for them. You could add a manual operated rear park brake for such emergencies but only after you have slowed down considerably.