See also:

Limitations
Strong sunlight, reflections, extreme light contrasts, the use of sunglasses, or if the driver is not looking straight ahead may make the visual warning signal in the windshield difficult to see ...

When does BLIS function
The system functions when your vehicle is moving at speeds above 6 mph (10 km/h). When you pass another vehicle: The system reacts when you pass another vehicle at a speed of up to 6 mph (10 km/h) ...

Severe strain on the brake system
The brakes will be subject to severe strain when driving in mountains or hilly areas, or when towing a trailer. Vehicle speed is usually slower, which means that the cooling of the brakes is less ...