Thesis (MScEng)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Capacity waste happens when right-turn vehicles have right-of-way during a
separate right-turn phase and lanes (e.g., through lanes) of the same approach of
the intersection cannot discharge vehicles during that green phase. Right-turn traffic
consumes the capacity which otherwise could be provided to through traffic
movements at an at-grade signalized intersection. Therefore, it is widely considered
that it would lower intersection capacity and increase total delay (Lin, Machemehl,
Lee & Herman, 1984).
The pre-signal strategy proposed in this research is specifically designed to improve
this problem. The following aspects of this strategy were studied in this research,
- Capacity benefits of this strategy,
- Relationships between the capacity and the length of sorting area (the area
between the two signals),
- Signal timing of both main signal and pre-signal,
- Clearance time of the sorting area,
- Main signal phasing options
- Signal coordination between the main signal and the pre-signal,
- Utilization of the sorting area, and
- Pre-signal strategy performance in a simulated environment. The results of this study showed that right-turn movement benefits significantly from
this pre-signal strategy. For example, right-turn capacity can be doubled if a presignal
is installed on one through lane of an approach with one right-turn lane.
It was also found, the maximum approach capacity benefit is not affected
significantly by the length of the sorting area for a given green period. The optimal
green time and the available pre-signal green time for right-turn movement were also
derived in this research. Different main signal phasing options were studied and
compared. Phasing options which fit the proposed pre-signal strategy were found.
Recommended values for right-turn green time of both signals were given based on
different lengths of sorting area. The case study, which compared the performance of some critical movements at the
intersection with and without the proposed pre-signal system, confirms the results
concluded in this study.
A potential problem with this strategy when applied at a real intersection is that it
may confuse drivers. Drivers need to be educated and will need time to get familiar
with this signal control method. / AFRIKAANSE OPSOMMING: Beskermde regsdraaifases vir verkeer by gelykvlak seinbeheerde kruisings gebruik
die kapasiteit wat benut kon word deur deurbewegings. Dit verlaag interseksie
kapasiteit en totale oponthoud verhoog.
Die voorseinstrategie wat in die navorsing studie voorgestel word is spesifiek
ontwikkel om die probleem op te los of te verminder. Die volgende aspekte van die
strategie is ondersoek in die navorsingsstudie:
- Kapasiteitsvoordele van die strategie.
- Die verhouding tussen die kapasiteit en die lengte van die sorteringsarea (die
area tussen die twee seine).
- Seintydstoedeling van beide die hoofseinfase en die voorseinfase.
- Ontruimingstyd van die stoorarea.
- Hoofseinfaseopsies.
- Seinkoordenasie tussen die hoofsein en die voorsein.
- Benutting van die sorterings area, en
- Voorseinstrategieprestasie in ‘n gesimuleerde omgewing. Die resultate bewys dat die regsdraaibeweging grootliks bevoordeel word nadat die
voorseinstrategie ingestel is. Byvoorbeeld, regsdraaikapasiteit kan verdubbel word
as ‘n voorseinfase ingestel word op een van die deurlane tesame met ‘n enkele
regsdraailaan.
Daar is ook gevind dat die kapasiteit nie grootliks beinvloed word deur die lengte van
die stoorgebied nie. Die optimale groentyd en die beskikbare voorsein groen tyd vir
die regsdraaibeweging is ook afgelei in die navorsing. Verskillende
hoofseinfaseopsies is bestudeer en vergelyk. Faseringsopsies vir die voorgestelde
voorseinstrategie is gevind. Voorgestelde waardes vir regsdraaigroentyd van
voorseine en hoofseine is bereken om kapasiteit te verbeter, gebasseer op
verskillende lengtes van die stoorarea.
Die gevallestudie wat die prestasie op ‘n aanloop met en sonder die voogestelde
voorseinstrategie vergelyk, bewys resultate wat ooreenstem met die bevindinge in
die studie. Die verwagte probleem met die voorseinstrategie, wanneer dit ingestel word by ‘n
werklike interseksie, is verwarring van die bestuurders. Bestuurders sal opgevoed
moet word en sal tyd nodig hê om gewoond te raak aan die voorseinmetode.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/96484 |
| Date | 03 1900 |
| Creators | Tang, Hao |
| Contributors | Andersen, Johann, Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 137 p. : ill. |
| Rights | Stellenbosch University |
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