Improvement of unsignalized intersections faced with poor visibility weather conditions on South African regional routes

Hunter, Jonathan Douglas (2022-04)

Thesis (MEng)--Stellenbosch University, 2022.

Thesis

ENGLISH ABSTRACT: When faced with poor visibility weather conditions such as thick fog and heavy rain, a driver may experience the feeling of uncertainty and discomfort when waiting to pull off to either cross or join a highspeed through road from a stationary position at a stop-controlled intersection. Poor visibility weather conditions have the ability to reduce the ability to correctly perceive speed and distance which proves difficult during pull off decision making, especially when vehicles approaching at highspeed become visible a lot closer to an intersection. This study has a focus on the improvement of unsignalized intersections faced with poor visibility weather conditions on South African regional routes. The study aimed to find an acceptable and implementable solution that would improve safety of road users by reducing the chance of collision. The solution should also improve the comfortability and certainty at an intersection when driving under poor visibility weather conditions while also maintaining the flow of through traffic and allowing the stationary vehicle to safely join the traffic. The study achieved the aims by collecting data for a solutions proposal. The data collection was carried out by selecting a study area from a fog and rain weather data analysis, performing a crash data analysis to validate the study problem and select intersections for traffic data observations that were later completed while also circulating a questionnaire for local residents that provided further validation of the existing study problem and provided insight into what local residents would view as an acceptable solution at dangerous intersections faced with poor visibility weather conditions in their area. The study concluded with a proposal that could be applied to any area that faces similar issues with poor visibility weather conditions and not just for the study area that was observed. The proposal acknowledged the challenges faced by regional route intersections (such as no access to a power supply, unlit, often poorly maintained and possibly budget constrained after the recent pandemic) and provided a range of solutions that could improve an intersection but ultimately, with further research, the proposed solution that would meet all aims of the included a hybrid model of a warning stop sign and an interactive stop sign that would be able to sense approaching vehicles and indicate to a stationary vehicle when it is safe to turn in a particular direction. Other key findings included the conclusion that drivers feel more discomfort and uncertainty at intersections under fog conditions compared to rain conditions and intersection approach speeds of vehicles are significantly decreased if a vehicle is waiting at a stop sign compared to when no vehicle is waiting at a stop sign.

AFRIKAANSE OPSOMMING: Wanneer 'n bestuurder met swak sig weerstoestande soos digte mis en swaar reën gekonfronteer word, kan 'n bestuurder die gevoel van onsekerheid en ongemak ervaar wanneer daar gewag wordom weg te trek om óf oor te steek óf by 'n hoëspoed-deurpad aan te sluit vanaf 'n stilstaande posisie by 'n stop-beheerde kruising. Weerstoestande met swak sigbaarheid lei tot die verminderde vermoë om spoed en afstand korrek waar te neem, wat moeilik is tydens aftrekbesluitneming, veral wanneer voertuie wat teen hoë spoedbeweeg , baie nader aan 'n kruising sigbaar word. Hierdie studie fokus op die verbetering van ongeseinde kruisings wat gekonfronteer word met swak sigbaarheid weerstoestande op Suid-Afrikaanse streekroetes. Die studie het ten doel gehad om 'n aanvaarbare en implementeerbare oplossing te vind wat die veiligheid van padgebruikers sal verbeter deur die kans op botsing te verminder. Die oplossing moet ook die gemak en sekerheid by 'n kruising verbeter wanneer daar onder swak sigweerstoestande gery word, terwyl dit ook die vloei van deurgaande verkeer behou en die stilstaande voertuig toelaat om veilig by die verkeer aan te sluit. Die studie het die doelwitte bereik deur data vir 'n oplossingsvoorstel in te samel. Die data-insameling is uitgevoer deur 'n studiegebied uit 'n mis- en reënweerdata- analise te kies, 'n ongelukdata-analise uit te voer om die studieprobleem te valideer en kruisings te kies vir verkeersdatawaarnemings wat later voltooi is, terwyl 'n vraelys vir plaaslike inwoners gesirkuleer is om verdere validering van die bestaande studieprobleem te verskaf asook insig in wat plaaslike inwoners as 'n aanvaarbare oplossing sal beskou by gevaarlike kruisings wat gekonfronteer word met swak sigbaarheidsweerstoestande. Die studie is afgesluit met 'n voorstel wat toegepas kan word op enige gebied wat soortgelyke probleme ondervind met swak sigbaarheid weerstoestande en nie net vir die studie area wat waargeneem is nie. Die voorstel erken die uitdagings wat streekroete-kruisings in die gesig staar (soos geen toegang tot 'n kragtoevoer, onverligte, dikwels swak onderhou en moontlik begroting beperk na die onlangse pandemie) en het 'n reeks oplossings verskaf wat 'n kruising kan verbeter, maar uiteindelik, met verdere navorsing, die voorgestelde oplossing wat aan alle doelwitte van die sal voldoen insluitend 'n hibriede model van 'n waarskuwing- stopteken en 'n interaktiewe-stopteken wat in staat sal wees om naderende voertuie waar te neemen aan stilstaande voertuiguie aandui te dui wanneer dit veilig is om in 'n bepaalde rigting te draai. . Ander sleutelbevindinge sluit die gevolgtrekking in dat bestuurders meer ongemak en onsekerheid by kruisings onder mistoestande ervaar, in vergelyking met reëntoestande, en kruisingsbenaderingspoed van voertuie word aansienlik verminder wanneer 'n voertuig by 'n stopteken wag in vergelyking met wanneer geen voertuig by 'n stilhouplek wag nie.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/124891
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