ST Engineering DriveSafe Intelligent Warning System

The DriveSafe Intelligent Warning System is an Advanced driver assistance system (ADAS) for heavy vehicles. For buses, it is designed to alert Bus Captains of objects such as other vehicles, cyclists and pedestrians approaching and within their blind spots while on the roads.

The system is jointly developed by the Land Transport Authority (LTA) and ST Engineering Land Systems. Formerly known as the Integrated Smart Advanced Warning Unit (I-SAW-U), the system was later renamed as “Drive Safe” – Intelligent Warning System for Bus & Heavy Vehicles, and was showcased at the 26th Intelligent Transport Systems (ITS) World Congress held in Singapore.

The DriveSafe system comprises a set of four cameras sensors and two ultrasonic sensors installed around the bus. When a vehicle, cyclist or pedestrian approaches the bus, the camera sensors detect them as obstacles. An alarm will sound and the location of the obstacle will be displayed visually on a new screen installed at the Driver’s Cockpit. DriveSafe 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.

I-SAW-U: Amber proximity alert on Driver Display
DriveSafe: Amber proximity alert on Driver Display

The screen reflects two levels of alerts based on the proximity of the obstacle: an amber alert when the obstacle is 1m away, and a red alert when the obstacle is between 0.5m to 0.8m away from the bus. These thresholds can be redefined in the future. In addition, the two ultrasonic sensors mounted on the roof of the bus are able to detect and warn drivers if they are about to hit an overhead obstacle.

Finally, the DriveSafe system also comes with additional features, such as blinker lights and buzzers mounted outside the bus, which can alert other road users, such as cyclists, if they are riding too close to the buses. These will be activated later during the trial.

An initial six-month trial was conducted in April 2018, with 20 public buses being equipped with the system.

Other Driver Assistance systems

The Mobileye Shield+ Collision Avoidance System is an alternative driver assistance system which also monitors the blind spots of the front, side and rear of the bus. As of April 2018, three buses are equipped with the system: SBS6650K (as part of a trial), as well as SG5999Z and SG4003D. Three cameras installed on the bus feed information to three separate indicator displays depending on the proximity of the potential hazard. More information about the system at the dedicated article.

In addition, SG4002G features a Surround View Camera System, which uses four cameras mounted on the bus (front, rear, both left and right sides) to generate a top-down view of the vehicle in real time, with audio alerts if the bus approaches too close to other road objects.

Land Transport Authority (LTA) Trial

On Monday, 16 April 2018, a six month trial of the DriveSafe system commenced (then known as I-SAW-U).

5 buses from each of the 4 Public Transport Operators (SBS Transit, SMRT Buses, Tower Transit Singapore & Go-Ahead Singapore) were installed with the I-SAW-U system for Bus Captains to provide feedback during operations. So far, only MAN A22 & MAN A95 buses were observed to be equipped with the system.

The buses installed with the I-SAW-U system are as follows:

LTA – ST Engineering I-SAW-U Trial
Operator Bus Model Bus Registration No.
SBS Transit MAN A22 SMB3076Y
SBS Transit MAN A22 SMB3079P
SBS Transit MAN A22 SMB3096P
SBS Transit MAN A22 SMB3097L
SBS Transit MAN A22 SMB3122Y
SMRT Buses MAN A95 SG5740C
SMRT Buses MAN A95 SG5741A
SMRT Buses MAN A95 SG5745P
SMRT Buses MAN A95 SG5747J
SMRT Buses MAN A95 SG5755K
Tower Transit MAN A22 SMB3001M
Tower Transit MAN A22 SMB3002K
Tower Transit MAN A22 SMB3003H
Tower Transit MAN A22 SMB3004E
Tower Transit MAN A22 SMB3005C
Go-Ahead MAN A95 SG5904Y
Go-Ahead MAN A95 SG5905U
Go-Ahead MAN A95 SG5906S
Go-Ahead MAN A95 SG5907P
Go-Ahead MAN A95 SG5908L

Subsequent Installations

In January 2019, several MAN A95 (Euro 6) and MAN A22 (Euro 6) buses were spotted with the I-SAW-U system installed. ST Engineering eventually rolled out the I-SAW-U system to fulfill the collision warning system requirements for its newly-delivered MAN Euro 6 buses.

The system was also installed on Linkker LM312 buses.


These buses can be identified by the external side-mounted blinkers and additional cameras at the rear of the bus.


2 thoughts on “ST Engineering DriveSafe Intelligent Warning System

  • 20 April 2018 at 3:04 AM

    STK missed out A24, which might be useful.

  • 19 April 2018 at 7:48 PM

    Mobileye is better. Because of these things, buses cannot enter the automatic bus wash machine


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