Advanced Driver Assistance System (ADAS) for buses

An Advanced Driver Assistance System (ADAS), also referred to as a Collision Warning System (CWS), is an onboard system installed on vehicles to assist drivers while driving. In the automotive industry, the individual features of ADAS systems (such as collision warning, lane departure warnings and other features) are collectively called Vehicle Safety Technology. ADAS improves driving safety by tackling human error, the leading cause of vehicle accidents.

On Singapore buses, ADAS systems are usually a suite of sensors installed around the bus paired with a display unit. Acting as an ‘extra pair of eyes’, the system alerting Bus Captains to vehicles, pedestrians and cyclists on the roads with visual and audible alerts, helping to reinforce safe driving behaviour and reduce the chance of accidents. Different ADAS systems offer different degrees of functionality, and some offer telematics capabilities as well.

The Land Transport Authority (LTA) is responsible for bus procurement and their specifications since the start of the Bus Contracting Model (BCM). While several types of ADAS systems have been trialled in the mid-2010s, the LTA made ADAS a mandatory requirement for buses procured starting from late-2017.

Anti-Fatigue Systems, which detect and counter driver fatigue, are covered under a separate article.

History

SBS Transit was the first Public Bus Operator to introduce ADAS systems on its fleet in November 2014 starting with the Mobileye 560 installed on 30 buses. It has since embraced the technology and equipped nearly 3,000 buses with the technology by end-2018.

Under the BCM, operators have also proposed ADAS installation on their fleet, such as SBS Transit when it clinched the Seletar and Bukit Merah bus packages. However, all buses are LTA-owned assets leased to operators. Should buses be transferred between operators, the uninstallation and reinstallation of ADAS systems represent an unnecessary burden.

From the standpoint of the LTA, it is hypothesized that the merits of the technology were accepted and eventually adopted into its requirements for its bus procurement. As a result, ADAS systems are a mandatory requirement for buses procured starting from late-2017. By making ADAS systems a part of the bus (and hence an LTA-owned asset), the burden of system maintenance could be streamlined and passed from individual bus operators to appointed contractors under warranty or other forms of contractual agreement, if any.

Furthermore, LTA and ST Kinetics have jointly developed an ADAS system (I-SAW-U) currently undergoing trials.


ADAS Systems in use

Mobileye 560 / Mobileye 630

Model Mobileye 560 (older) / Mobileye 630 (newer)
Functionality Headway measurement, Pedestrian & Vehicle collision alert, Lane Departure Warning
Speed alert (Mobileye 630)
Buses Most SBS Transit Buses, SMRT Training Buses, some Go-Ahead Singapore buses, SG5999Z, SG4002G

The Mobileye 560 and Mobileye 630 Advanced Driver Assistance System (ADAS) alerts drivers to vehicles, pedestrians and cyclists on the roads, while also featuring a lane departure warning. It is the basic Mobileye system installed across many buses. In addition, the system offers Fleet Management System (FMS) integration allowing for Intelligent Event Data Recording (EDR), and connectivity abilities with other external devices using Bluetooth wireless technology.

The system comprises a windshield-mounted Vision Sensor Unit (containing a camera and an image processor), a buzzer and a dashboard-mounted EyeWatch Display Unit for visual directional warnings and numerical headway measurement display.

The newer Mobileye 630 offers similar functionalities but elements on the Display Unit are indicated differently.

In a May 2016 press release, SBS Transit announced that 750 buses would be installed with Mobileye 560 system by that year, and more than 3,000 buses would be equipped with it by the end of Year 2018, with the eventual goal of fleet-wide implementation. Starting from 2018, a newer model (Mobileye 630) was installed instead of the Mobileye 560.

Background Data collection

In addition to real-time alerts presented to BCs, the Mobileye system also records additional parameters that are logged and uploaded to a cloud server. This enables SBS Transit to monitor every instance of dangerous driving behaviour across all buses installed with the system. As such, Mobileye also functions as a telematics system.

Main Article: Mobileye collision alert system


Mobileye Shield+

Model Mobileye Shield+
Functionality Pedestrian & Vehicle sideswipe collision alert (As an add-on to the Mobileye 560 / 630)
Buses Mercedes-Benz Citaro (SBS6650K), Volvo B8L (SG4003D), MAN A95 3-Door Concept Bus (SG5999Z)
The detection range of the Mobileye Shield+'s three cameras. Camera 4 in this diagram is not installed.
The detection range of the Mobileye Shield+’s three cameras. Camera 4 in this diagram is not installed.

The Mobileye Shield+ Collision Avoidance System is an improvement of the existing Mobileye 560 and Mobileye 630, with two additional cameras installed at the rear of the bus. Covering both the left and right sides of the vehicle, drivers are alerted to cyclists, pedestrians and motorcyclists within their blind spot while making a turn. These are connected to two additional large-sized display units mounted near the left and right rearview mirrors, easily seen by Bus Captains when they glance at their mirrors.

The Mobileye 560 as described in the above section is also a part of the Mobileye Shield+ system. Using a windscreen-mounted camera and dashboard display unit, it alerts drivers to vehicles, pedestrians and cyclists on the roads, while also featuring a lane departure warning. As such, the Mobileye Shield+ system utilises a total of 3 cameras.

The system was first installed on an SBS Transit Mercedes-Benz Citaro (SBS6650K) in January 2017 for a six-month trial and has since been also installed on SG4003D and SG5999Z.

The Mobileye 560, Mobileye 630 and Mobileye Shield+ systems are developed by Mobileye, an Israeli technology company founded in 1999.

Main Article: Mobileye collision alert system


ST Kinetics I-SAW-U Driver Warning System

Model ST Kinetics I-SAW-U Driver Warning System
Functionality Pedestrian & Vehicle collision alert (all sides), Overhead collision alert, blinker lights and buzzers
Buses MAN NL323F (SBS Transit & Tower Transit – 5 units each), MAN A95 (SMRT & Go-Ahead – 5 units each)

The I-SAW-U 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. 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.

 

I-SAW-U: Driver Display mounted next to Trapeze CFMS
I-SAW-U: Driver Display mounted next to Trapeze CFMS

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 I-SAW-U 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.

Main Article: ST Kinetics I-SAW-U Driver Warning System


Surround View Camera System

Model Model Unknown  (Cameras + Display unit)
Functionality Real-time display with Proximity alert
Buses 3-door MAN Lion’s City SD (SG4002G)

Four cameras mounted on the bus (front, rear, left and right sides) generate a top-down view of the vehicle in real time, with visual and audio alerts if the bus approaches too close to other road objects. The system enhances the driver’s situational awareness on the roads.


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