Conference Proceedings (Civil Engineering)

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Browsing Conference Proceedings (Civil Engineering) by browse.metadata.advisor "Bruwer, Megan"

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    A study to measure the accuracy of speed data reported by floating car data in rural areas
    (Stellenbosch : Stellenbosch University, 2023-03) Kiautha, Antony Mugambi; Bruwer, Megan; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Intelligent Transportation Systems (ITS) technologies are becoming routine worldwide, offering newer methods of obtaining traffic data. Recently, on-board vehicle navigation devices have offered Global Positioning System (GPS) data spanning an entire road network referred to as Floating Car Data (FCD). The accuracy of FCD is critical to evaluate traffic information and inform stakeholders involved in transportation planning in different regions. This study was conducted to measure the accuracy of speed data reported by commercial FCD in rural areas. The study compared benchmark speed data and TomTom historical speeds on 12 rural routes and 7 urban routes in the Western Cape in South Africa. The benchmark data was provided by the Western Cape Department of Transport, collected through loop inductance. Data collected was analysed for weekdays (Monday to Friday) in the month of February 2019 and aggregated over 1-hour time intervals. This was done to give a true representation of traffic patterns and analyse traffic patterns before the COVID-19 pandemic. To evaluate accuracy, probe penetration rate, signed error bias (SEB), average absolute (AASE) and signed error were determined. The minimum probe penetration rate considered for accuracy measurements was 4% and the maximum allowable errors for SEB, AASE and signed error were ±7.5 km/hr, ±10 km/hr and ±10 % respectively. The SEB and AASE accuracy measures showed that FCD reported speeds were consistently lower in the urban areas while some routes in the rural areas recorded higher FCD speed estimate than the benchmark data. Probe penetration rates for both urban and rural areas indicated that a high probe penetration rate is not directly proportional to a high level of speed data accuracy. This study is relevant because evaluation of commercial FCD accuracy has not been examined in rural areas and it is an informative research to assist in improving the transportation industry across the globe and especially in developing countries.