Дисертації з теми "Traffic signs and signals Victoria"

Thesis (M.S.)--West Virginia University, 2009.
Title from document title page. Document formatted into pages; contains viii, 85 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 79-82).

Thesis (PhD)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: The debilitating social, economic and environmental ramifications of traffic congestion are experienced in large cities the world over. The optimisation of traffic signal timings at signalised road intersections attempts to mitigate the extent of these adverse effects of traffic congestion by reducing the delay time experienced by vehicles in a transport network. Today, traffic signal control schemes may be classiffied into one of two main classes, namely fixed-time traffic signal control strategies, which are typically cyclic in nature, and vehicle-actuated traffic signal control strategies, which are typically acyclic in nature. Generally, cyclic control strategies tend to lack exibility, and are unable to adapt to short-term uctuations in traffic ow rates, resulting in green times that are either too long or too short. On the other hand, acyclic control strategies tend to lack coordination between intersections, resulting in vehicles being required to stop at the majority of signalised intersections they encounter. Self-organising traffic signal control has been proposed as an attractive alternative form of control which both exhibits exibility and facilitates a global coordination between intersections as a result of localised signal switching policies. Two examples of existing self-organising traffic signal control algorithms from the literature include an algorithm proposed by Lammer and Helbing in 2008 and an algorithm proposed by Gershenson and Rosenblueth in 2012. These algorithms have been shown to outperform both optimised fixed-time traffc signal control techniques as well as state-of-the-art vehicle actuated trffic signal control techniques, in terms of reducing vehicle delay time in a transport network. A draw-back of both of these self-organising approaches, however, is that their effective operation relies on carefully selected parameter values; poorly selected parameter values may render these algorithms very ineffectual. In this dissertation, three novel self-organising traffic signal traffic control algorithms are proposed. These three algorithms assume the use of existing radar detection sensors mounted at the intersection to provide the necessary input data. The radar detection sensors are capable of detecting and tracking individual vehicles approaching an intersection, providing real-time information pertaining to their physical dimensions, velocities, and ranges from the intersection in terms of both time and distance. The three traffic signal control algorithms are free of any user-specialised parameters, and instead rely solely on the data provided by the radar detection sensors to inform their signal switching policies. The first of these traffic signal control algorithms is inspired by inventory control theory, and draws parallels between the monetary costs typically considered in inventory control models and the delay time costs associated with traffic control at signalised intersections, which the algorithm attempts to minimise. The second novel traffic control algorithm is inspired by the chemical process of osmosis in which solvent molecules move unaided from a region where they are highly concentrated, across a semi-permeable membrane, into a region of high solute molecule concentration. The algorithm models vehicles approaching an intersection as solvent molecules and the physical space available for the vehicles to occupy once they have passed through the intersection as solute molecules. Following this analogy, the intersection is considered to be the semi-permeable membrane. The third traffic control algorithm is a hybrid of the inventory and osmosis-inspired algorithms together with an intersection utilisation maximisation technique, which prevents unnecessary or prolonged underutilisation of an intersection. The three novel trafficc control algorithms, together with the algorithms of Lammer and Helbing, and of Gershenson and Rosenblueth, as well as a fixed-time control algorithm, are implemented in a purpose-built microscopic traffic simulation modelling framework. Several measures are employed to evaluate the relative performances of the algorithms. These measures include the usual mean and maximum resulting delay times incurred by vehicles and the saturation level of the roadways in the transport network, as well as three novel performance measure indicators which include the mean number of stops made by vehicles, their mean normalised delay time and the mean normalised number of stops made. The algorithms are compared in the context of a linear corridor road network topology as well as a grid road network topology under various traffic ow conditions. The overall performance of the novel hybrid traffic signal control algorithm is found to be superior for the corridor road network topology, while the performance of the osmosis-inspired algorithm is found to be superior for the grid road network topology.
AFRIKAANSE OPSOMMING:Die negatiewe sosiale, ekonomiese en omgewingsimpak van verkeersopeenhoping word in groot stede regoor die w^ereld ervaar. Die doel met die optimering van verkeersligwerkverrigting by straatkruisings is om die omvang van hierdie negatiewe impak tee te werk deur die vertraging van voertuie in 'n vervoernetwerk te verminder. Hedendaagse verkeersbeheeralgoritmes kom in een van twee hoofklasse voor, naamlik vaste-tyd beheerstrategiee, wat gewoonlik siklies van aard is, en beheerstrategiee gebaseer op voertuigopsporing, wat tipies asiklies van aard is. Oor die algemeen beskik sikliese beheerstrategiee nie oor genoegsame buigsaambeid om aan te pas by kort-termyn fluktuasies in verkeersvloei nie, wat tipies daartoe lei dat hul groentye spesifiseer wat of te lank of te kort is. Aan die ander kant is asikliese beheerstrategiee nie daartoe in staat om koordinasie tussen naasliggende straatkruisings te bewerkstellig nie, wat weer daartoe lei dat voertuie genoodsaak word om by die oorgrote meerderheid straatkruisings op hul pad te stop. Die self-organiserende beheer van verkeersligte is as 'n aantrektlike, buigsame alternatief voorgestel wat in staat is om globale koordinasie tussen naasliggende straatkruisings as gevolg van gelokaliseerde seinstrategiee te bewerkstellig. Twee voorbeelde van bestaande self-organiserende verkeersbeheeralgoritmes in die literatuur is die algoritmes wat in 2008 deur Lammer and Helbing en in 2012 deur Gershenson en Rosenblueth voorgestel is. Daar is aangetoon dat hierdie algoritmes daartoe in staat is om ge-optimeerde vaste-tyd beheerstrategiee sowel as gevorderde strategiee gebaseer op voertuigopsporing uit te stof in terme van 'n vermindering van die vertraging van voertuie in 'n vervoernetwerk. 'n Nadeel van beide hierdie self-organiserende benaderings is egter dat hul doeltreffende werkverrigting berus op versigtig-gekose parameterwaardes; willekeurige parameterwaardes mag lei na hoogs ondoeltreffende werkverrigitng van die algoritmes. Drie nuwe self-organiserende verkeersbeheeralgoritmes word in hierdie proefskrif voorgestel. Hierdie drie algoritmes maak vir hul toevoerdata staat op die beskikbaarhed van bestaande radar opsporingsensors wat by straatkruisings geinstalleer is. Die sensors is daartoe in staat om individuele voertuie wat 'n straatkruising nader, op te spoor, te volg en intydse data oor hul fisiese dimensies, snelhede, en afstande na die kruising (in terme van beide tyd en afstand) te lewer. Die drie algoritmes bevat geen gebruikers-gespesifiseerde parameters nie, en maak in plaas daarvan slegs gebruik van die sensortoevoerdata om hul beheerstrategiee te bepaal. Die eerste van hierdie verkeersbeheeralgoritmes is deur die teorie van voorraadbeheer geinspireer en maak gebruik van parallelle tussen die monet^ere kostes wat tipies in voorraadbeheermodelle voorkom en die kostes in terme van vertragingstyd wat met verkeersbeheer by straatkruisings aangegaan word, en wat deur die algoritme geminimeer word. Die tweede verkeersbeheeralgoritme is deur die chemiese proses van osmose geinspireer, waar molekules van 'n oplossingsmiddel sonder eksterne hulp vanaf 'n gebied waar hul in hoe konsentrasie voorkom, deur 'n gedeeltelik-deurlaatbare membraan beweeg na 'n gebied waarin hul ook in hoe konsentrasie, maar in opgeloste vorm voorkom. Die algoritme modelleer voertuie wat 'n straatkruising nader as die molekules van die oplossingsmiddel en die fisiese ruimte wat aan die ander kant van die kruising beskikbaar is om deur voertuie beset te word, as molekules in opgeloste vorm. In hierdie analogie word die kruising self as die gedeeltelik-deurlaatbare membraan beskou. Die derde algoritme is 'n hibriede strategie waarin elemente van die eerste twee algoritmes in samewerking met 'n tegniek vir die maksimering van straatkruisingsbenutting gekombineer word, en wat wat ten doel het om onnodige of verlengte onderbenutting van die kruising te vermy. Hierdie drie nuwe verkeersbeheeralgoritmes word, tesame met die bestaande algoritmes van Lammer en Helbing, en van Gershenson en Rosenblueth, asook 'n vaste-tyd beheeralgoritme, in 'n mikroskopiese verkeersimulasiemodelleringsraamwerk wat spesifiek vir die doel ontwerp is, geimplementeer. Verskeie maatstawwe word ingespan om die relatiewe werkverrigting van die algoritmes te evalueer. Hierdie maatstawwe sluit in die gebruiklike gemiddelde en maksimum vertragingstye van voertuie en die versadigingsvlak van strate in die vervoernetwerk, sowel as drie nuwe maatstawwe, naamlik die gemiddelde aantal stoppe deur voertuie, hul genormaliseerde vertragingstye en die gemiddelde, genormaliseerde aantal stoppe. Die algoritmes word in die kontekste van 'n line^ere topologie van opeenvolgende straatkruisings en 'n netwerktopologie van reghoekige straatblokke onder verskeie verkeersdigthede met mekaar vergelyk. Daar word bevind dat die nuwe hibriede algoritme die beste vaar in die line^ere topologie, terwyl die osmose-ge inspireerde algoritme die ander algoritmes uitstof in die straatblok-netwerktopologie.

Thesis (M.S.)--University of Missouri-Columbia, 2005.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (July 11, 2006) Includes bibliographical references.

Thesis (Ph. D.) -- University of Maryland, College Park, 2006.
Thesis research directed by: Applied Mathematics and Scientific Computation Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

Thesis (M.S.)--West Virginia University, 2001.
Title from document title page. Document formatted into pages; contains viii, 68 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 61-62).

This report represents a concentrated effort that determines the feasibility of audible pedestrian signals. These signals are devices which give auditory cues to help the visually impaired cross safely at difficult intersections. Surveys were sent out to over 100 organizations, audible signal manufacturers, and cities who have knowledge of the devices, and responses were analyzed. The devices were found to be feasible but only at certain complex and confusing intersections. Twelve criteria for the installation of the devices were developed as were twelve criteria for the operation of the devices. Buzzers, constant tones, bird calls, and voice signals were examined by obtaining information from traffic engineers who had experience with each sound. It was determined that intermittent tones were the most effective for human localization. For the most widely used devices, cost data were developed for the products, installation, and maintenance. A partial listing of the U.S. and foreign cities which have the devices was compiled along with a partial listing of audible signal manufacturers. The problems the visually impaired face as well as their suggested solutions are listed. Topics for further study include the use of hand-held devices which activate sound signals at intersections and the development of tone schemes for 4-leg and multi-leg intersections which are not north south and east-west. An additional topic for future study is the development of tone schemes for traffic circles.
Master of Science

Thesis (M.S.)--West Virginia University, 2006.
Title from document title page. Document formatted into pages; contains viii, 173 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 75-76).

Thesis (MPhil (Philosophy))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: This study investigated the practice of language use on road signs in Switzerland. The language used in public spaces constitutes our image of a specific place to a remarkable degree. We are constantly exposed to signs, whether road signs, advertisements or notifiers. These signs not only convey information such as “Caution”, “Final sale” or “Speed limit 60 here”, but also highlight aspects of culture and, where written text appear on them, aspects of the language(s) used in that area. Language use within the public space enables us to conceptualize, as well as recognize, the ways in which language use occurs, often (but not always) informing us whether a country is monolingual, bilingual or multilingual. In addition, these signs also indicate how language use is linked to other processes such as globalisation, social change and cultural heritage. The main purpose of this thesis was to establish how language is used on road signs in presentday, officially multilingual Switzerland. In this regard, three Swiss cantons (in which bilingual or multilingual societies are found) were investigated as to the language(s) – or lack thereof – which appear on their road signs, as well as to the order in which these languages appear. Specifically, bilingual or multilingual signs, as well as so-called Bildersprache (“picture language”, in other words on a board or plaque with a picture, symbol or other image on it), were studied in these cantons. Data for this research consists of photographic material (taken during visits to the study areas) as well as interview data. It was found that the social and political identities, as well as the economic interests, of language groups in a particular area affect the design and placement of road signs in that area. The results of this study serve as a framework for future research, and the photo material enables us, to a certain extent, to see how an apparently stable language system (such as the multilingualism found in Switzerland) encounters changes due to internal and external influences, but also how creative language can be.
AFRIKAANSE OPSOMMING: In hierdie studie is die taalgebruik op padtekens in Switserland ondersoek. Die taalgebruik in openbare plekke vorm tot ’n merkwaardige mate die beeld wat ons van ’n spesifieke plek het. Ons word konstant blootgestel aan tekens, hetsy padtekens, advertensies of kennisgewings. Hierdie tekens verskaf nie net inligting soos “Versigtig”, “Finale uitverkoping” of “Spoedgrens 60” nie, maar beklemtoon ook kulturele aspekte en, in daardie gevalle waarin geskrewe teks op tekens verskyn, ook aspekte van taal/tale wat in die betrokke gebied gebesig word. Taalgebruik in die openbare ruimte help ons om die wyses waarop taalgebruik voorkom te konseptualiseer en te herken, en dui gereeld (maar nie altyd nie) vir ons aan of ’n land eentalig, tweetalig of veeltalig is. Verder gee die tekens ook ’n aanduiding van hoe taalgebruik gekoppel is aan prosesse soos globalisasie, sosiale verandering en kulturele erfenis. Die hoof doel van hierdie tesis was om te bepaal hoe taal in die hedendaagse Switzerland op padtekens gebruik word. Drie Switserse kantons (met tweetalige en veeltalige gemeenskappe) is in hierdie verband ondersoek in terme van die taal/tale – of die gebrek daaraan – wat op padtekens verskyn asook die volgorde waarin hierdie tale op die padtekens verskyn. Spesifiek tweetalige of veeltalige tekens asook sogenaamde Bildersprache (“prentetaal”, met ander woorde ’n bord met ’n prent, simbool of ander voorstelling daarop) is in hierdie kantons bestudeer. Die data vir hierdie navorsing bestaan uit fotografiese materiaal (wat verkry is tydens besoeke aan die studie-areas) sowel as inligting wat verkry is deur onderhoudvoering. Daar is bevind dat die sosiale en politiese identiteite, sowel as die ekonomiese belange, van taalgroepe in ’n spesifieke area die ontwerp en plasing van padtekens in daardie area beïnvloed. Die resultate van hierdie studie dien as ’n raamwerk vir toekomstige navorsing en die fotomateriaal stel ons tot ’n sekere mate in staat om vas te stel hoe ’n klaarblyklik stabiele taalsisteem (soos die veeltalige een wat in Switserland aangetref word) veranderinge weens interne en eksterne invloede kan ervaar, maar ook hoe kreatief taal kan wees.

Road safety is an aspect of major concern on road networks, not only on a local scale in South Africa, but also on a global scale. South Africa is experiencing an unacceptably high rate of fatal road traffic crashes and as a result has one of the highest per capita rate of road fatalities in the world. The Global Plan for the Decade of Action for Road Safety 2011 – 2020 was published in 2011 by the World Health Organisation (WHO) to guide and assist countries with the improvement of road safety. The management of vehicle speeds is one of numerous important interventions identified in the Global Plan. The technical and economic feasibility of using a specific Road safety is an aspect of major concern on road networks, not only on a local scale in South Africa, but also on a global scale. South Africa is experiencing an unacceptably high rate of fatal road traffic crashes and as a result has one of the highest per capita rate of road fatalities in the world. The Global Plan for the Decade of Action for Road Safety 2011 – 2020 was published in 2011 by the World Health Organisation (WHO) to guide and assist countries with the improvement of road safety. The management of vehicle speeds is one of numerous important interventions identified in the Global Plan. The technical and economic feasibility of using a specific technology, namely Vehicle Activated Signs (VAS), to contribute to the overall improvement of road safety on a national level in South Africa were investigated, with particular emphasis on the improvement of road safety through the reduction of fatal road traffic crashes. VAS are part of a range of measures that can be used to curb vehicle speeds, similar to conventional measures like speed cameras and traffic calming devices. VAS technology has seen limited use in South extrapolation of results from SCC’s VAS effectiveness study, and the application of these results to the South African road safety and road user statistics for the one year period March 2011 to March 2012. Key factors relating to speed and general driver obedience were also taken into consideration. It was established that the use of VAS would lead to a moderate reduction in the number of fatal road traffic crashes that occur annually, which in turn holds financial and socio-economic benefits for South Africa. A comparison of selected products available from two South African based electronic road sign manufacturing companies with conventional VAS was also carried out, focussing on product function, use and cost. It has been concluded that it would be technically and economically feasible to introduce VAS on the South African road network to improve the prevailing road safety situation.

An intensive examination was conducted to test the credibility of current traffic signal change interval policies founded on a kinematic equation developed nearly 30 years ago. The investigation involved the review of relevant literature as well as an extensive collection of data. The literature review and data analysis revealed that current change interval policies rely on the disproven assumption that traffic decelerates at a constant rate. The data analysis also demonstrated that traffic approach speed and deceleration distance affect the manner in which deceleration occurs. Based on the data analysis, an alternative treatment of the kinematic equation is proposed using surrogate deceleration rates. The surrogate rates offer a pragmatic set of input for the kinematic equation. Therefore, rather than yielding a change interval based on an inaccurate assumption, agencies can implement change intervals which are responsive to local traffic.

Thesis (M.S.) University of Missouri-Columbia, 2004.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 29, 2006) Vita. Includes bibliographical references.

When a traffic signals malfunction monitoring unit detects a problem with a traffic signal such as the simultaneous display of green indications to conflicting movements or loss of power to some signal heads, the signal is automatically placed into flash mode as a safety precaution. Signals can have either red/red malfunction flash mode or yellow/red malfunction flash mode, and the mode cannot change by time of day or day of week. This study analyzed traffic operation at 34 instances of yellow/red malfunction flash and 9 instances of red/red malfunction flash in the Atlanta, Georgia area. Many of these instances were during high volume periods. A high level of driver confusion exists at malfunction flash intersections. The rate at which through major street drivers (i.e. those facing a flashing yellow signal) stopped exceeded 75 percent at some yellow/red flash intersections. This creates a safety hazard for other major street drivers who are not expecting vehicles to stop, and for minor street drivers who cannot tell what type of control is being presented to cross traffic or do not understand that vehicles are not required to stop when approaching a flashing yellow indication. Furthermore, high stopping rates at a flashing yellow signal eliminate many of the operational benefits that yellow/red flash is assumed to have over red/red flash. Based on the findings of this study, the use of red/red flash should be the primary flash mode and possibly used exclusively. Requiring all vehicles to stop will improve safety conditions and not have large operational impacts at intersections where a majority of major street vehicles are already stopping at a flashing yellow signal. Yellow/red flash may be an acceptable malfunction flash mode at the intersection of a very large street and a very small street, but additional measures would be required at these intersections to address potential driver confusion.

Dissertation for the degree of Doctor of Science in Technology--Helsinki University of Technology, Espoo, 2002.
"ISSN 0781-5816." Includes bibliographical references (p. 65-71). Available online as a PDF file via the World Wide Web.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Hunter, Michael; Committee Member: Meyer, Michael; Committee Member: Rodgers, Michael. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M. S.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2009.
Committee Member: Hunter, Michael; Committee Member: Meyer, Michael; Committee Member: Rodgers, Michael. Part of the SMARTech Electronic Thesis and Dissertation Collection.

When a malfunction occurs in a traffic signal controller cabinet, the signal is automatically placed into malfunction flash mode as a safety precaution. During this event, drivers are presented with one of two possible scenarios: flashing yellow on the major street and flashing red on the minor street, or flashing red on all the approaches. Volumes and percentages of car stopping were collected at fifty-one study intersections in the Atlanta regions. By means of the VISSIM microsimulation software a sample of intersections was simulated under the two malfunction scenarios and the signalized one. Based on output data such as delay and queue, the performances of each simulated intersection is compared and recommendations on which mode of flash must be used in case of malfunction are provided.

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.

The objective of this research is to investigate different propagation models to determine if specified models accurately predict received signal levels for short path 900 MHz spread spectrum radio systems. The City of Denton, Texas provided data and physical facilities used in the course of this study. The literature review indicates that propagation models have not been studied specifically for short path spread spectrum radio systems. This work should provide guidelines and be a useful example for planning and implementing such radio systems. The propagation model involves the following considerations: analysis of intervening terrain, path length, and fixed system gains and losses.

Traffic signs, which are extremely important for traffic safety, aims to regulate traffic by providing information about the characteristics of road and road environment for drivers. The success of traffic signs mainly rely on the easy comprehensibility of its meaning in a short time. Further more, today&rsquo
s global economies and transportation systems emphasize the need for more universial traffic signs which was the main motivation of two main treaties on traffic signs
Vienna Convetion in 1968 and European Aggreement Treaty in 1971, which are signed and followed by Turkey. For an effort to increase traffic safety, a Subcommittee of the Turkish Highway Traffic Safety (THTS) Council requested the determination of comprehensibility of critical signs with higher probability of impact on traffic safety selected by a group of experts from engineers and law enforcement agencies in a survey study. The survey questionnaire included 30 selected traffic signs (including two prohibition signs omitting oblique bar recently changed as a part of the European Union Participation Process) and 9 control group signs, a total of 39 traffic signs, and driver characteristic questions, such as gender, age, educational background, etc. to reveal insights about a) the level of comprehensibility of different groups of traffic signs and and b) driver characteristics that may affect the comprehensibility of these signs. A pilot study in the city of Ankara is conducted over a sample of 1,478 surveys. Answers for the meaning of each sign are coded using a scale of five (opposite, wrong, no comment, partially correct and correct responses). The results showed that the control group signs have very high comprehensibility as expected, while some of the critical signs were not known much, or mistaken for others, even mistaken for opposite meanings. The certain loss of comprehensibility of the traffic signs changed recently is seen in the comparative analysis of the signs before and after the change, as well as significant shift towards an opposite meaning. The significance of driver characteristics (gender, education, occupation etc.) affecting the comprehensibility of the traffic signs varies among traffic signs and characteristics. As the result of this study, (THTS) Council decided to support traffic and driver education more and mass promotion of mis- or un-comprehended signs without searching for more local solutions or versions.

Thesis (M.S.)--West Virginia University, 2009.
Title from document title page. Document formatted into pages; contains xi, 102 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 77-79). WVU users: Also available in print for a fee.