Ghosts in the machine

A car I was test-driving once came to a stop without me pressing the brake pedal. Traffic was barely moving, and a woman was walking between cars, crossing from one opening to the next. As she appeared to head toward the side of my vehicle, the collision-avoidance system suddenly applied the brakes.

Some new cars can brake even when there is no apparent danger ahead, a phenomenon known as phantom braking.

Depending on the vehicle, automatic emergency braking uses cameras, radar or both to detect pedestrians and other vehicles ahead. It calculates how close they are and how quickly the distance is closing, then applies the brakes if a collision appears likely, even before the driver can react.

Pedestrians crossing between slow-moving cars are a common sight on Metro Manila streets. They can suddenly change direction, prompting the automatic braking system to intervene even in crawling traffic.

At low speeds, the sudden stop startled me enough to think I had hit something. However, on a highway, the same unexpected braking could put the car’s occupants as well as the motorists following close behind at risk.

In the US, road safety regulators have investigated complaints of vehicles slowing unexpectedly while driver-assistance features were in use. Other cases involved automatic braking systems reacting unnecessarily near railroad crossings and overpasses, prompting manufacturers to issue software updates.

Research by the Insurance Institute for Highway Safety found that vehicles equipped with pedestrian-detecting automatic braking had 27 percent lower pedestrian crash rates and 30 percent lower pedestrian injury crash rates than those without the feature.

The same research found no statistically significant reduction in pedestrian crashes on unlit roads at night, something worth remembering during today’s All Souls’ Day cemetery visits and throughout the year.

Heavy rain or dirt on the camera can make it harder for the car to detect hazards. If it keeps braking for no apparent reason, have the system checked at the dealership, including any available software updates, rather than simply switching off the feature.

I still don’t know whether the car correctly anticipated a collision or was simply being overly cautious. Or something else.

As for the woman, I doubt she realized she had stopped a car with her mere presence. I’m quite certain she wasn’t the white lady of Balete Drive. It was broad daylight, after all.

Then again, this happened along Kalayaan Avenue, right beside Manila South Cemetery.