ROAD DESIGN


Road design includes a broad scope of activities from road network planning through to detail geometric design, tender documentation and construction supervision. It incorporates specialised fields such as pavement design, stormwater design, traffic signal design and street light design. ITS Engineers has been involved in all of the above fields on projects ranging from freeway interchanges to local access roads for township development. This includes work for both the public and private sector.

Key focus areas are:

Road network planning

Road networks are developed over time and implementation is largely influenced by changes in land use. Land use planning affects trip generation which in turn affects the need for roads. The hierarchy of roads is a key component of road network planning as freeways and major arterials have an exclusive mobility function while residential streets primarily provide access. Provincial and local authorities need Road Master Plans to ensure that road networks are developed to optimally support existing and new developments in terms of both mobility and access. ITS Engineers has developed Road Hierarchy and Road Master Plans for various municipalities.

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Geometric design

Geometric design not only includes the horizontal and vertical alignment of roads, but also the design of interchanges and intersections. It also incorporates the design of road markings and traffic signs in accordance with the relevant design manuals and statutory requirements. High order roads such as freeways and major arterials require route determination and preliminary design to be done in advance. Some road authorities have specific geometric design standards as well as standard specifications and/or tender documentation. Geometric design standards are dependant on design speeds and the various authorities have specific requirements in this regard. Adherence to EIA requirements also affects most road designs. ITS Engineers has experience in route determination, preliminary designs as well as detail designs for the various road catagories.


Stormwater design

Stormwater design forms an integral part of road design. Effective drainage is not only a road safety requirement but also ensures that properties adjacent to roads are not damaged as a result of stormwater being concentrated at certain locations. As is the case with geometric design, some authorities have specific guidelines regarding stormwater management and design. Due to the high cost of stormwater infrastructure as well as the high cost of repairing damage in case of flooding, it is essential that specific attention be paid to stormwater design. ITS engineers has been involved with the design of various stormwater systems including channels, culverts and urban stormwater systems.


Tender documentation and evaluation

ITS Engineers has been responsible for all aspects of tendering procedures which includes:

Preparation of Tender and Contract Documents

  • Chairing and conducting site inspections
  • Evaluation of tenders and preparing tender evaluation reports

Working with clients in both the private and public sector has given ITS Engineers exposure to preparing tender documents based on various Conditions of Contract (FIDIC, GCC) and technical specifications (COLTO, SABS 1200). Tender documents are prepared according to the latest CIDB requirements. Site inspections are held to ensure that tenders are fully informed on the contractual and technical specifications as well as site conditions. On receipt of tenders, an evaluation report is prepared in accordance with the client’s guidelines. The report includes a full assessment of the tenders which includes financial risk assessment, technical ability and experience and cost analysis.


Construction supervision

Over the years ITS Engineers has been responsible for monitoring the construction of projects ranging from traffic signals, road upgrades, new roads, street lighting, intelligent transport infrastructure to interchange upgrades. To ensure that the highest standards are achieved, procedures and quality control systems have been established which conform to the highest industry standards. All aspects of construction monitoring from site handover, quality control and monitoring, measurement and payment and dispute resolution are dealt with.

Traffic signals

Apart from the operating speed and the amount of lanes, the capacity of a road is affected by the type of intersection control. Road capacity can be significantly increased by providing signalised intersections or roundabouts. Signalised intersections take less space and the construction cost is usually less expensive than roundabouts. Traffic signals are designed by taking into account the lane configuration and the amount of peak hour trips for each movement through an intersection. It is a specialised field and experience is essential to effectively use the design software that is available. ITS Engineers has vast experience in the design and implementation of traffic signals.

Access management

Access management must be applied on all roads which have a function of providing for both mobility and access. These include major arterials, minor arterials, activity arterials and activity streets. Ineffective access management leads to road congestion, accidents and ultimately the stagnation of business-areas because of businesses moving out as a result of traffic congestion. Access management addresses issues such as speed limits, lines of no access and measures to enforce it, intersection/access spacing as well as the type of intersections/accesses to be used. It is a way of balancing the need for access with the need for mobility and is especially important where new developments take place along existing roads. ITS Engineers has experience in the compilation of access management plans for local authorities.

Road light design

Road lighting design includes the determination of mast and pole layouts, mounting heights and luminaire type in order to provide lighting levels to international standards. Consideration is also given to the depreciation of lamps, lamp replacement cycles and frequency of maintenance. ITS has experience in the design and implementation of several road lighting projects, and in particular is involved with the deployment of the first intelligent lighting systems in South Africa. These systems use telemanagement to remotely control the lighting levels or switch the lighting from a central point, such as a transport management centre. Lighting levels required are dependent on the actual traffic volumes, and can therefore be reduced after the evening peak and increased before the winter morning peak, resulting in energy savings of up to 20%. Intelligence in lighting extends to remote monitoring of luminaires for faults, which is of great assistance in proper maintenance. Examples of such intelligent lighting installations are the R300 and N1 (T9-1) in Cape Town.

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