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Powered Two-wheelers (PTW) Integrated Safety

Final Report Summary - PISA (Powered Two-wheelers (PTW) Integrated Safety)

The aim of the PISA project was to develop and use new technologies to provide integrated safety systems for a range of powered two wheelers (PTWs). The systems were developed, in order to improve primary safety and so that they could be linked to secondary safety devices. The project aimed to develop reliable and fail-safe systems which offer improved safety.

The rationale for the PISA project was that the research would contribute to the general EU target of 50 % reduction in road accident fatalities; the PISA objectives were aligned with this ambition. PISA also contributed to India's automotive policy by enhancing the safety of PTW designs.

The quantified objectives for the integrated system were to combine sensors and an advanced braking and suspension system to:
a) avoid 50 % of accidents where a collision was not inevitable;
b) reduce the impact speed, and hence reduce the injury severity by one MAIS integer for 50 % of accidents where a collision was inevitable;
c) prevent 50 % of the single vehicle loss of control accidents.

The scientific and technical objectives were to:
- identify the most frequent causes - precipitating factors and contributory factors of PTW accidents and how the rider interacted with the PTW during the pre-crash phase by analysing PTW accident data and video tapes recorded at dangerous junctions;
- examine rider and bike interaction when riding along known accident sites using an instrumented PTW;
- assess and measure rider behaviour in dangerous manoeuvres identified from the accident analysis and instrumented PTW by using computer models, including human muscle activity, that replicate the interaction between a rider and a PTW;
- assess and measure the PTW behaviour and response in dangerous manoeuvres, identify potential areas for improvement by use of triggered control mechanisms on for instance suspension, brakes, steering;
- identify existing technologies and safety systems in passenger cars and assess their usability in PTWs;
- develop a PTW safety system that integrates sensors, warning devices - visual, acoustic, and / or mechanical - an intelligent braking system and automatically variable suspension that will reduce the incidence and severity of PTW accidents;
- assess the costs of the PTW safety system and the benefits in terms of reduction in accidents and injuries;
- fit the prototype integrated safety system to at least two PTWs and evaluate the PTWs on a test track and road using a range of subjects (riders);
- invite various dignitaries to observe the behaviour and hence the benefits of the integrated system during track and road tests.

The project was structured into the following work packages (WPs):

WP 2: User needs and requirements
The activities proposed in WP2 were planned to make efficient use of existing data and information and, only where needed, collect new information. WP2 therefore used the outputs of other projects to provide in-depth accident cases and analysis of motorcycle publishable final activity report accident statistical data in order to both understand all of the relevant issues and to determine and prioritise the potential for active and integrated safety solutions. The intention of WP2 was that real-world information would form the basis of the recommendations for the subsequent development and implementation of the PISA systems within WPs 3, 4 and 5. The work done under WP2 involved work on accident statistics, literature review about the state of the art, in-depth accident cases, in-depth video, user information, scenario interventions and priorities, and estimate of impact of deriver driver assistance functions.

WP 3: System specifications
The objective of WP3 was to define the specification of the components, which form part of the integrated safety system installed onto the PTW which aim to detect dangerous situations and prevent potential accidents. The integrated safety system included a module to determine the dynamic state of a motorcycle in real-time, during both normal driving conditions and emergency situations.

WP 4: System development
The central work package objective was the development of a motor driver assistance system (MDAS) for motorcycles. The outputs of WP2 and WP3 formed the framework parameters of the MDAS. The MDAS was comprised of the set of sensors and actuators which are mainly provided by the project partners. The system development included the development of a warning strategy / collision mitigation strategy, which operated, based on the sensor system data and the development of an appropriate HMI. Simulations of the MDAS including HMI were performed at TNO automotive / TNO human factors in order to determine the performance of the PISA system (benefit with respect to the bike without the system) during accidents, and the influence on the tuning parameters on the behaviour / performance.

WP 5: System integration
The objective of WP5 was to produce and implement the integrated safety systems, developed in WP4 (system development) into a range of full-scale PTWs (at least one scooter and one motorcycle) from the participating PTWs manufacturers, to be able to test the integrated systems in WP6 (validation and evaluation). During the project, given the different safety systems considered within the project, it was decided to build two full-scale PTWs.

WP5 was divided into three tasks:
- preparation of the PTWs and realisation of the safety devices for implementation;
- validation of the sensors / actuators;
- implementation of the integrated safety systems developed in WP4.

In WP 5, the systems (sensors and actuators) designed and adapted were implemented in two full participating motorcycle manufacturers (MAL, TVSM) provided the PTWs. Before integration of the systems in the PTWs, prototypes of the selected safety devices were developed and tests were performed in laboratory conditions. After integration of the safety devices in the PTWs, functional tests were performed to prepare the PTWs for WP6.

WP 6: Evaluation and validation
The objective of WP 6 was to test and evaluate the integrated safety system, according to the requirements developed in the packages. A test plan and road / track tests were devised. A comprehensive system validation test programme comprising many thousands of test runs was carried out by TRL and the WP6 partners which validated the performance of the following PISA systems:
- Active braking (AB) - Low level autonomous braking at 0,25 g with pre-warning.
Results showed that for AB, the mean triggering reliability decreased with test speed, from 91 % at 35 km/h to 58 % at 55 km/h. Reliability increased with increasing AB trigger setting (range 58 % to 89 %). This showed that the system was more reliable when set to activate very close to impact (mitigation system).
- Enhanced braking (EB) - Additional braking effort applied (brake assist) in an emergency.
For the tests on the EB system, results showed that, on average, and with EB on, a rear brake application by the rider delivered a stopping distance between 2.1 % and 6.8 % better than a test rider applying both front and rear brakes.
- Combined braking (CB) - Distribution of brake forces between the front and rear wheels.
For the CB system, results showed that the addition on CB had a significant (P < 0.001) positive effect on stopping distances, with average distances decreasing by 18,5 %.
- Distance support (DS) - Automatic throttle inhibition for critical time headways.
For the DS system, results showed that there was no clear improvement of the car-following task.

The results showed that the PISA system was predicted to deliver significant casualty reductions although the extent to which these address the accident and casualty reduction targets set by the PISA project was difficult to assess. The tests within the PISA project focussed on system validation with consideration of system evaluation. Although these tests showed that the system had the potential to function as intended and demonstrated good performance improvements in specific, 'uncluttered' test conditions, the test results could not be related to real-world system effectiveness. This was because insufficient information exists with which to robustly define the system effectiveness at the level required to perform a full cost benefit analysis.

Technological developments have been made in parallel to PISA by vehicle manufacturers and other EC and national funded projects, such as ABS, combined and traction control. The PISA project has made a good contribution to industry and policy makers as it has provided a demonstration that the integrated safety technologies can be combined and integrated successfully. Furthermore, the PISA project has defined a range of PTW accident countermeasures based on a sample of European accidents. This provides important accident causation information and could be used by the research community or by policy makers to target the most effective strategies to reduce European PTW accidents.

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