Mazda 3 Owner's Manual page 226

When Driving
Radar Sensor
NOTE
In the following cases, the radar sensor may not be able to detect vehicles ahead or
obstructions.
The rear surface of a vehicle ahead does not refl ect radio waves effectively, such as
an unloaded trailer or an automobile with a loading platform covered by a soft top,
vehicles with a hard plastic tailgate, and round-shaped vehicles.
Vehicles ahead with low vehicle height and thus less area for refl ecting radio waves.
Visibility is reduced due to a vehicle ahead casting off water, snow, or sand from its
tyres and onto your windscreen.
The boot/luggage compartment is loaded with heavy objects or the rear passenger
seats are occupied.
Ice, snow, or soiling is on the front surface of the front emblem.
During inclement weather such as rain, snow, or sand storms.
When driving near facilities or objects emitting strong radio waves.
In the following cases, the radar sensor may detect vehicles in the opposite lane or
surrounding obstructions, or it may not be able to detect vehicles ahead or obstructions.
The beginning and end of a curve.
Roads with continuous curves.
Narrow lane roads due to road construction or lane closures.
The vehicle ahead enters the radar sensor's blind spot.
The vehicle ahead is running abnormally due to accident or vehicle damage.
Roads with repeated up and down slopes
Driving on poor roads or unpaved roads.
The distance between your vehicle and the vehicle ahead is extremely short.
A vehicle suddenly comes close such as by cutting into the lane.
To prevent incorrect operation of the system, use tyres of the same specifi ed size,
manufacturer, brand, and tread pattern on all four wheels. In addition, do not use
tyres with signifi cantly different wear patterns or tyre pressures on the same vehicle.
(Including the temporary spare tyre)
If the battery power is weak, the system may not operate correctly.
When driving on roads with little traffi c and few vehicles ahead or obstructions for the
radar sensor to detect, Smart Brake Support/Smart City Brake Support (SBS/SCBS)
indicator light temporarily illuminates, however, this does not indicate a problem.
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