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oa Civil Engineer in South Africa - Comprehensive traffic observations in South Africa : technical paper

 

Abstract

A pilot study on Comprehensive Traffic Observations (CTO) was carried out on a 600 km long route between Johannesburg and Durban from October 1983 to January 1985. Traffic was observed at seven CTO stations placed on different types of road comprising this route. Electronic observation equipment of the Traffic Engineering Logger (TEL) type was used supplemented by, in one instance, a Traffic Axle Weight Classifier (TAWC) for a more accurate estimation of axle load. The observations were carried out in week-long blocks, repeatedly, for 12 consecutive months, on a 24-hours a day basis.


The pilot study concluded that CTO are capable of yielding accurate estimates of the average annual daily traffic (AADT) - the maximum likely error of the AADT near Alberton being about 1,2 per cent. If the TEL measurements are supplemented by a sample of TAWC axle measurements, the accuracy of E80 estimation can also be improved considerably. Speed measurements on individual vehicles - an instrinsic feature of CTO - opens a new dimension in establishing the degree to which service may be appreciated by road users. This is done by the evaluation not only of average speeds, but also of traffic densities, the extent of dose following and platooning of vehicles.
Remote monitoring of traffic through the instant transfer of data from certain stations to a central computer has been implemented on a routine basis. The supporting software has been developed or modified, from programs residing in TEL units to the main-frame computer programs required for smooth operation of a Traffic Data Bank. An information dissemination system has been introduced. According to the pilot study, the CTO system is regarded as a success and an extension of CTO into a network of national roads is considered to be not only a viable proposition but also desirable for effective national road management.

'n Loodsstudie van Omvattende Verkeerswaarnemings (OV) is op 'n 600 km roete tussen Johannesburg en Durban vanaf Oktober 1983 tot Januarie 1985 uitgevoer. Verkeer is by sewe verteenwoordigende OV-punte waargeneem. Traffic Engineering Logger (TEL)'-tipe elektroniese waarnemingsapparaat is gebruik en is, in een geval, aangevul deur 'n Traffic Axle Weight Classifier (TAWC), 'n instrument vir die raming van aslaste. Die waarnemings is uitgevoer in week-tydperke, herhaaldelik vir 12 opeenvolgende maande, op die basis van 'n 24-uur dag.


Met die loodsstudie is bevind dat OV in staat is om noukeurige ramings van die jaarlikse gemiddelde daaglikse verkeer (JGDV) te lewer; die maksimum waarskynlike fout van die JGDV naby Alberton is ongeveer 1,2 persent. Indien die TEL-waarneming aangevul word deur 'n monster van TAWC-aslaswaarnemings, kan die noukeurigheid van 'n E8O-raming ook aansienlik verbeter word. Waarnemings van individuele voertuie - 'n inherente eienskap van OV - verleen 'n nuwe dimensie aan die bepaling van die mate waartoe dienspeil deur padgebruikers waargeneem word.
Afstandswaarneming van verkeer, deur middel van onmiddellike oorsein van data van sekere stasies na 'n sentrale rekenaar per telefoon, is op 'n roetinegrondslag in werking gestel. Programmatuur is ontwikkel en aangepas vir 'n reeks wat strek van programme wat in die TEL-eenhede gesetel is tot by dié wat nodig is vir die daarstelling van 'n Verkeersdatabank. 'n lnligtingverspreidingstelsel is ook in werking gestel. Die resultate van die loodsstudie het getoon dat die OV-stelsel suksesvol funksioneer. Uitbreiding van die OV-netwerk op alle nasionale paaie word tans oorweeg, nie alleen as 'n lewensvatbare onderneming nie, maar ook as noodsaaklik vir die doeltreffende bedryf van nasionale paaie.

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/content/civeng1/27/10/EJC24968
1985-10-01
2016-12-05
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