The development and evaluation of a performance-based standards approach for regulating the use of heavy vehicles in South Africa.
Loading...
Date
2013
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The regulation of the use of vehicles on the road network is aimed at ensuring acceptable
safety and recovery of road maintenance costs, as well as minimising congestion, road
wear, excessive noise and air pollution. The traditional approach of regulating heavy
vehicles is prescriptive, i.e. enforcing regulations that primarily limit the mass and
dimensions of these vehicles. This approach is generally favoured because such regulations
are easy to understand and enforce. However, an underlying disadvantage is that the
prescriptive approach does not always adequately safeguard the dynamic performance of
heavy vehicles while travelling on the road. Principle-based and performance-based
standards are primarily aimed at specifying desired outcomes, rather than how these
outcomes should be achieved.
Under a performance-based standards (PBS) approach, performance measures (such as
low-speed swept path, rearward amplification, load transfer ratio and high-speed
offtracking) are utilised to specify the performance required from vehicles. Although more
complex to regulate, a PBS approach has a number of potential benefits such as: (a)
improved vehicle safety, (b) improved productivity, (c) reduced infrastructure wear and
emissions, (d) a more optimal use of the existing road network, and (e) the encouragement
of innovation in vehicle design.
The aim of this research was to apply, refine and demonstrate an alternative approach to the
design and operation of heavy vehicles in South Africa with improved outcomes in terms
of road transport productivity, vehicle safety performance, emissions, congestion and
preservation of road infrastructure. The research included the development and
implementation of a PBS demonstration project in South Africa and the monitoring and
evaluation of PBS demonstration vehicles operating in the forestry industry in the
provinces of KwaZulu-Natal and Mpumalanga. Evaluation focused on improvements in
productivity (fuel efficiency and trip reduction) and load control with reference to initial
results regarding road wear and safety performance.
Results show a significant improvement in payload control and fuel efficiency of the PBS
vehicles compared with the baseline vehicles. This also resulted in a reduction in CO2
emissions per ton.km. Road wear assessments of PBS and baseline vehicles showed that in
some cases a reduction in road wear of up to 200% per ton of payload can be achieved
through the use of PBS vehicles. Safety assessment results of four PBS vehicle designs
showed various shortcomings of prescriptive baseline vehicles in terms of the performance
standards.
Description
Ph. D. University of KwaZulu-Natal, Durban 2013.
Keywords
Trucks--Performance--South Africa., Trucks--Standards--South Africa., Trucks--Sizes--South Africa., Trucks--Safety regulations--South Africa., Trucks--South Africa--Weight., Roads--South Africa--Maintenance and repair., Theses--Bioresources engineering.