Bus captains will have an extra pair of "eyes" to look out for cyclists and pedestrians in their blind spots, and to warn them to take preventive action.

As part of a six-month trial, 20 public buses have been fitted with smart camera sensors which can analyse and detect objects in front and at the sides of the vehicles.

They are linked to a display panel on the bus driver's dashboard, which gives different audio and visual warnings based on how close the pedestrians, cyclists or motorcyclist may be.

Deployment of the system, called the Integrated Smart Advance Warning Unit (I-SAW-U), was announced yesterday.

Jointly developed by the Land Transport Authority (LTA) and Singapore Technologies Kinetics (ST Kinetics), I-SAW-U will be evaluated before the authorities decide whether to extend it to the more than 5,000 buses across the island.

ST Kinetics principal engineer Lewis Tan said: "Currently, bus captains use mirrors to check their blind spots... With our systems, we are able to capture, in advance, the possible obstacles that are in front or at the side of the vehicles, to allow them (the drivers) to stop, or slow down in time."

Mr Tan said the system uses algorithms to filter out inanimate objects and focus on relevant subjects, such as pedestrians and cyclists.

ADVANCE WARNING SYSTEM Currently, bus captains use mirrors to check their blind spots... With our systems, we are able to capture, in advance, the possible obstacles that are in front or at the side of the vehicles, to allow them (the drivers) to stop, or slow down in time. MR LEWIS TAN, principal engineer of ST Kinetics, which jointly developed the driver-assistance system with LTA.

I-SAW-U also provides alerts if the bus is travelling too close to a vehicle in front, if a pedestrian steps in front of the bus or if the bus captain strays off his lane.

In addition to the four camera sensors, there are two ultrasonic sensors mounted on the roof of the bus to warn drivers if they are about to hit an overhead obstacle.

Advanced driver-assistance systems such as I-SAW-U are not new in the market - SBS Transit, for example, has fitted its bus fleet with the Israeli-designed Mobileye.

The Straits Times understands that I-SAW-U also comes with additional features, such as blinker lights and buzzers mounted outside the bus, which can warn other road users, such as cyclists, if they are riding too close to it. These will be activated later during the trial.

When asked, Mr Tan declined to reveal how much the I-SAW-U system costs.

An industry source estimates that the Mobileye Shield+ system, which is designed for buses, costs about $8,000 to install.

An LTA spokesman said it will review the results of the trial, which involves all four bus operators - SBS Transit, SMRT, Go-Ahead Singapore and Tower Transit Singapore - before deciding on the next course of action.

Go-Ahead bus captain Md Ahzman Tumin said I-SAW-U can provide him with an extra pair of "eyes" to look out for cyclists who veer into his blind spot when he is making a turn. "We are still focused on the road, and have to check our side mirrors and turn our heads to check, but it is an additional form of help," said the 52-year-old driver.