Comparison of USA and Australian Mobility Device Users’ and Ambulant Bus Users’ Views of Restraints on Public Buses

Many older people use powered wheelchairs and mobility scooters to access the community on buses but have increased injury risk if the mobility device tips or slides. Wheelchair tie-down and occupant restraint systems (WTORS) are mandated on USA transit buses, and their introduction investigated in Australia. This study examined the views of mobility device and ambulant bus users in the USA and Australia on WTORS. A Qualtrics survey with 448 respondents showed strong support for WTORS use and found the most important factors underpinning use were Safety, Comfort, and Transit time. US research indicates dwell time while fitting WTORS is 4 minutes, and participants reported 5.65(SD3.06) minutes is acceptable. There was no difference in USA and Australian participants who have slid or tipped in their device, despite being restrained in the USA: X2(1,n=220)=.053,p=.53,phi-.016). This research suggests all bus users are supportive of WTORs, but their effectiveness requires investigation.

A validation sensor based on carbon-fiber-reinforced plastic for early activation of automotive occupant restraint systems

In the automotive industry, sensors and sensor systems are one of the most important components in upcoming challenges like highly automated and autonomous driving. Forward-looking sensors (radar, lidar and cameras) have the technical capability to already provide important (pre-)crash information, such as the position of contact, relative crash velocity and overlap (width of contact) before the crash occurs. Future safety systems can improve crash mitigation with sophisticated vehicle safety strategies based on this information. One such strategy is an early activation of restraint systems compared with conventional passive safety systems. These integrated safety systems consist of a combination of predictive forward-looking sensors and occupant restraint systems (airbags, belt tensioners, etc.) to provide the best occupant safety in inevitable crash situations. The activation of the restraint systems is the most critical decision process and requires a very robust validation system to avoid false activation. Hence, the information provided by the forward-looking sensor needs to be highly reliable. A validation sensor is required to check the plausibility of crucial information from forward-looking sensors used in integrated safety systems for safe automated and autonomous driving. This work presents a CFRP-based (carbon-fiber-reinforced plastic) validation sensor working on the principle of change in electrical resistance when a contact occurs. This sensor detects the first contact, gives information on impact position (where the contact occurs) and provides information on the overlap. The aim is to activate the vehicle restraint systems at near T0 (time of first contact). Prototypes of the sensor were manufactured in house and manually and were evaluated. At first, the sensor and its working principle were tested with a pendulum apparatus. In the next stage, the sensor was tested in a real crash test. The comparison of the signals from the CFRP-based sensor with presently used crash sensors in the vehicle highlights its advantages. The crash event can be identified at 0.1 ms after the initial contact. The sensor also provides information on impact position at 1.2 ms and enables a validation of the overlap development. Finally, a possible algorithm for the vehicle safety system using forward-looking sensors with a validation sensor is described.