Vulnerable road users (VRU) are those users who are at great risk because of insufficient physical protection or because of relative high speed difference with potential conflicting modes (Vulnerable road users diagnose of design and operational safety problems and potential countermeasures, PIARC, 2016).
Through this definition a specific attention is given to four main categories of road users, i.e:
Although there are few standards and guidelines concerning human factors of ITS for these groups of people, vulnerable road users are likely to benefit from a range of safety-enhancing ITS and supporting standards and guidelines on their design and implementation. (See Road Safety)
Accessibility or "ability to access" often focuses on people with disabilities or special needs and their right of access, enabling the use of assistive technology.
This technology can include ITS to improve the capabilities of individuals with disabilities in the road context. Few standards or guidelines exist but ITS which is implemented via web applications can take advantage of published guidelines for accessibility. The Web Accessibility Initiative (WAI) has developed the Web Content Accessibility Guidelines (WCAG) which explains how to make Web content accessible to everyone, including people with disabilities.
Accessibility legislation in some countries has prompted the development of guidelines for disabled persons to access public transport (such as those published by the National Disability Authority in Ireland in 2005). This includes human factors issues.
With an increasing number of older drivers, automotive technology that helps keep older drivers safe is expected to grow in importance. Technology including ITS may help to prolong safe mobility particularly in suburban and rural areas, where public transportation options are limited. Many ITS devices may be developed to assist older drivers with aspects of their driving task. “Design for all” is an important concept as designs benefitting the least fit, older person, are likely to help drivers of all ages and skill levels. The Massachusetts Institute of Technology’s (MIT) Age-Lab, is for example, doing work in this area. Older road users include pedestrians and cyclists. Specific designs for older road users are being developed – although standards and guidelines on HMI are yet to emerge.
A range of technology is emerging based on ITS and cooperative systems that can potentially alert a driver to the presence of a cyclist or pedestrian (for example, in their blind spot). General ITS and human factors guidelines will apply to these situations although little specific guidance is currently available.
As with other vulnerable road users, riders of powered two wheelers (PTW) are likely to benefit from a range of safety-enhancing ITS for drivers and supporting standards and guidelines for their design and implementation.
ITS for PTW and other light vehicles is largely in the research and development phase and many ITS applications could be used to improve rider safety including Adaptive Cruise Control, Incident Warning, Blind Spot Monitoring, Forward Collision Warning, Obstacle Warning, Automatic eCall.