In a recent survey by JD Power, 35% of new car owners equipped with advanced safety systems reported that the automatic braking system prevented a collision within the first 90 days of ownership. This is an interesting statistic because there is no way to track accidents that never happened. But if 35% of drivers say an automatic braking system prevented a crash in 90 days, the other 65% will probably use it within the next 12 months.
The next question is how will the brakes be working in the three or four years when the brake pads need to be replaced? Also, will the owner make sure the replacement brake pads meet or exceed the specifications of the original pads? Automatic braking systems and many autonomous safety systems are only as effective as the brake pads they use to make corrections. These systems need predictable friction levels from the brake pads to produce the intended result. If a brake pad does not match the friction levels or has poor construction, it will require more hydraulic pressure or time to perform an automatic emergency correction. Both defects equal greater stopping distances. But what can really impact the original and replacement brake pads is corrosion.
In a field study by the Global Brake Safety Council (GBSC), 11.2% of the pads recovered from the field showed signs of edge lift or rust jacking due to corrosion with a partial gap to the full-width gap of the backing plate. This condition can cause the friction material to separate from the backing plate leading to loss of braking power and vehicle instability. In 5.3% of the cases, a substantial part of friction was separated from the pad or backing plate. This means that the vehicle the brake pads came off had a compromised brake system with significant increases in stopping distance and possible stability issues under heavy braking, like during automatic braking events.
The life of a brake pad is tough. Brake pads are exposed to corrosive elements and heat over thousands of miles. Many economy OE and replacement pads use a layer of paint or powder coating to protect the backing plate. This is applied after the friction material is mated with the backing plate. Paints and coatings protect only the exposed metal surfaces and not the interface between the backing plate and friction material.
Some OE brake pads and premium replacement brake pads use a galvanized backing plate that protects against corrosion. Galvanization is a plating process where an outer layer of zinc is applied to the backing plate by electroplating. Galvanization is performed before the friction material is attached to the backing plate. By galvanizing the surface between the backing plate and friction material, the possibility of corrosion that can cause edge lift and delamination is reduced. This means that the automatic braking system performance will not be compromised by delaminated friction material.
In another survey by JD Power, 22% of potential new car buyers surveyed say they will consider a “highly automated” vehicle for their next purchase. But, are they willing to pay for it when it comes to service the brakes? They better be ready if they plan for the automatic braking to work as the vehicle ages.