Nissan's active approach

The trend towards active cruise-control systems is clearly gathering pace, with several other manufacturers having subsequently joined the radar-guided bandwagon.

In a nutshell, these systems operate via a bumper-mounted radar sensor and clever electronic wizardry that modulate braking and throttle inputs (or provide an audible warning) to ensure you don't get end up in the boot compartment of the vehicle in front.

We should point out that real-world experience suggests these systems aren't infallible, but more on that later.

Nissan says the new system is especially useful in heavy traffic "when frequent braking is required". In these situations, if the driver releases the accelerator pedal or is not actively pressing it, the system automatically applies the brakes.

In cruising mode, if the system determines that braking is required, an indicator appears on the instrument panel and a buzzer sounds simultaneously. The accelerator pedal then automatically moves upward to assist the driver in switching to the brakes.

The technology is the latest innovation Nissan's Safety Shield 2 concept, an accident prevention and management approach that the company says is based on the idea of "vehicles that help protect people".

The company has set itself the ambitious goal of halving (by 2015) the number of fatal and serious injuries involving Nissan vehicles as compared to the 1995 level.

However, cars with overzealous "on-board nannies" have their fair share of critics, and, as mentioned earlier, they're not foolproof.

Mercedes-Benz was left red-faced a few months ago when its Distronic Plus crash-avoidance system failed to function in a televised display, resulting in a brand-new S-Class ploughing into a stationary car in front of a shocked audience.

The system had apparently performed flawlessly in earlier outdoor testing, but the steel walls of the Mercedes Safety Centre (where the televised display was conducted) are said to have bamboozled the crash-avoidance system's radar unit.