The evaluation and testing of mobile ITS interventions on speed compliance in the minibus taxi industry of South Africa

Akoku Ebot Eno Akpa, Nelson (2015-12)

Thesis (MEng)--Stellenbosch University, 2015.

Thesis

ENGLISH ABSTRACT: Informal public transport in South Africa, dominated by minibus taxis is noted for poor compliance, and has been shown to disregard posted speed limits on long-distance trips. They go as far as driving over the di erentiated speed limit of the lighter passenger vehicles used for private transport. This work compares and evaluates improvements in their speed compliance using two renowned interventions: automated Average Speed Enforcement (ASE), and auditory Intelligent Speed Adaptation (ISA). The feasibility of fuel economy existing as a self-regulatory incentive for speed compliant driving is investigated, together with the impact of each intervention on fuel consumption rates. The main ndings were that with minibus taxis, ASE is not well understood and needs ISA as a complementary intervention, and safe driving can increase driver remuneration from fuel costs. Average Speed Enforcement is an emergent alternative to instantaneous speed enforcement to improve road safety. This study involves a mixed methods approach in understanding driver response to the system on the R61 Between Beaufort West and Aberdeen in South Africa. A spatio-temporal quantitative study of speed compliance is conducted. Various speed metrics are measured prior to, and during enforcement, and ASE impact on crash risk and injury severity is also examined. These measurements are taken on the enforcement route and on control routes having similar characteristics. Two main modes of transport in the region are considered, namely minibus taxis and passenger vehicles. A qualitative study is also conducted to evaluate the relationship between speed compliance and understanding of the system. Results show that for passenger vehicles, the ASE system led to a reduction in mean speed on the enforcement and adjacent control routes. However, ASE appears to have no in uence on minibus taxis, which could be linked to limited understanding on ASE operation. This study also tests and evaluates the impact of an auditory ISA intervention, applied at various levels, on the speeding behaviour of the seemingly intransigent minibus taxi industry. The experiment evaluates the same ASE section on the R61, to which the minibus taxi drivers were seemingly impervious. Various speed metrics, as well as their statistical relevance and the e ect sizes are evaluated. Results show that the auditory ISA intervention has a clear impact on speeding behaviour, both when applied at an audible level that can be drowned out by a radio, and even more so at a loud level. The impact on speeding is signi cant, with speeding frequency (both time and distance) reducing by over 20 percentage points. Also, although the drivers showed little or no behavioural change when driving on the ASE route, introduction of the ISA system resulted in signi cant changes bringing violation frequencies down to 47.4% from 81.2% on the enforcement route. These changes brought about lower fuel consumption rates especially with the ISA system, and drivers can increase their remuneration by a minimum of about 120% and by up to 214% from the fuel budget if they drive safely.

AFRIKAANSE OPSOMMING: Informele publieke vervoer in Suid-Afrika, gedomineer deur minibus taxi's is bekend vir slegte gehoorsaamheid, veral met betrekking tot spoed beperkinge op lang afstand reise. Hulle gaan so ver as om oor die gedi erensieerde spoedlimiet van ligter passasiersvoertuie te gaan, wat gebruik word vir private vervoer. Hierdie werk vergelyk en evalueer verbeterings in hulle spoed nakoming deur gebruik te maak van twee bekende intervensies: outomatiese Gemiddelde Spoed Handhawing (GSH), en ouditiewe Intellegente Spoed Aanpassing (ISA). Die lewensvatbaarheid van ekonomiese branstof gebruik as 'n self-regulerende aansporing vir spoedlimiet handhaving word ondersoek, tesame met die impak van elke intervensie op brandstofgebruik. Die hoof bevindinge vir minibus taxi's was dat GSH nie goed verstaan is nie en benodig ISA as 'n kompliment^ere intervensie, sowel as die feit dat veilige bestuur die drywer se vergoeding deur middel van laer brandstof kostes kan verhoog. Gemiddelde Spoed Handhawing is 'n opkomende alternatief tot Intellegente Spoed Aanpassing met die hoop om padveiligheid te verbeter. Hierdie studie bevat 'n gekombineerdemetodes benadering om die bestuurders se reaksie met betrekking tot die sisteem op die R61 tussen BeaufortWes en Aberdeen in Suid-Afrika te bekom. 'n Tydruimtelike kwantitatiewe studie van spoed gehoorsaamheid is gedoen. 'n Verskeidenheid spoed statistieke is gemeet, voor, sowel as gedurende implimentering. Daar is ook gekyk na GSH se impak op botsingrisiko en beseringsintensiteit. Hierdie metings is geneem op die implimenteringsroete sowel as die beheerroete, elk met ooreenstemmende eienskappe. Die twee hoof vervoermiddels in die omgewing is oorweeg, naamlik minibus taxi's en passasiersmotors. 'n Kwalitatiewe studie is gedoen om die verhouding tussen spoed gehoorsaamheid en begrip van die sisteem te evalueer. Resultate wys dat vir passasiersmotors, lei die GSH na 'n vermindering in gemiddelde spoed op die ge mplimeenteerde sowel as die ooreenstemmende beheer roete. Egter, blyk dit asof die GSH geen invloed het op minibus taxi's, wat gekoppel kan wees aan min/geen begrip oor die gebruik van die GSH sisteem. Hierdie studie toets en evalueer ook die implak van 'n ouditiewe ISA intervensie, geimplimenteer op verskeie vlakke op die spoed gedrag van die onversetlike minibus taxi bedryf. Die eksperimente evalueer dieselfde GSH roete op die R61, waaraan minibus taxi bestuurders blyk om min aandag aan te gee. Verskeie spoed statistieke, sowel as hulle statistiese relevansie en die inpak van hul e ekgroottes is ge evalueer. Resultate wys dat die ouditiewe ISA intervensie 'n duidelike impak het op spoed gedrag, beide wanneer dit ge mplimeenteer word op 'n hoorbare vlak wat sagter is as die radio, sowel as, en self beter wanneer, dit harder is as die radio. Die impak op die spoed is merkwaardig; die spoed frekwensie (beide spoed en afstand) verminder met meer as 20 persentasiepunte. Alhoewel die bestuurders min of geen gedragsverandering gewys het indien hulle op die GSH roete gery het nie, met die implimentering van die ISA sisteem het dit gelei tot merkwaardige veranderings in oortredings frekwensie; 'n daling na 47.4% vanaf 81.2% is opgemerk. Hierdie veranderinge het laer brandstofverbruik na gebring, veral met die ISA stelsel, en bestuurders kan hul vergoeding verhoog met 'n minimum van ongeveer 120% tot en met 214% van die brandstof begroting as hulle veilig ry.

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