Although light rail is rightfully regarded as a safe mode of transport (in 2009 a UITP report* showed that accidents per kilometre were four times lower for trams than for cars), all operators still seek opportunities to improve safety standards wherever practical.
For example, driving a tram 'on sight' for a whole shift in all conditions can prove a challenging task and so Advanced Driver Assistance Systems (ADAS) have often been considered as a means of providing additional support for driver teams.
Until recently, progress on ADAS has been slow: though common in the automotive industry, adapting the technology for light rail has often proven too costly due to the relatively low volumes involved. However, technological advances mean operators are now looking at ADAS as a viable option.
HTM tram system fitment of ADAS
Following a successful testing programme, the public transport operator for the Dutch city of The Hague, HTM, announced plans to install a smart braking aid across its fleet of Avenio city trams.
As the first ADAS to be installed onboard a tram fleet in the Netherlands, there was no pre-defined admission approach that could be used. So HTM reached out to Ricardo for technical support in determining the approach for admission of the ADAS add-on and developing the supporting documentation.
Ricardo developed an admission approach according to the EN 50126 standard, combining the accepted Railway standard with our experience of automotive sensor technology and the comparable ISO 26262 standard for Functional Safety.
Our added value consisted of:
- Developing the system description in close cooperation with the supplier, describing exactly how the system will function and how it will be integrated in the existing vehicles.
- Performing the risk assessment and compiling the hazard log, agreed by all relevant stakeholders, including tram drivers, maintenance personnel, safety personnel and the system manufacturer.
- Defining a testing & monitoring plan for the high risk items that were identified, to guide the trial period of the system.
The results of the tests – which involved driving 500,000 km over the course of a year – proved most drivers could quickly adjust to driving with the braking aid.
The opinions of the driver teams would be crucial in determining the system's long term potential and, as reported by HTM, feedback was mostly positive about the use of ADAS. For example, some drivers did indicate that it was difficult to deal with the occasional false positives generated in specific driving conditions, such as tunnels, but the feedback in general stated that the more time they spent with the system, the easier it became to operate.
Ricardo’s ambition in Connected & Automated Vehicles leads us to offer added value across all transportation domains, leveraging our Automotive knowledge in Railway applications and vice versa. Through our involvement in cutting edge technology projects such as Autonomous Shuttle buses, Automatic Train Operation and Truck Platooning, we aim to provide valuable insights for our clients, helping them improve the safety and reliability of their operations.