Humans are in general poor at making judgments that adhere to the logical principles of probability theory. One demonstration of this is termed the “conjunction fallacy”: judging a conjunction (A&B) as being more probable than its constituent (A). Systematic commitment of the conjunction fallacy has been shown in numerous studies on probability judgments. Different actions to remedy the fallacy have been suggested. According to the nested-sets hypothesis, when the nested-set structure of a problem becomes clear (i.e. the relation between categories and subcategories), then the conjunction fallacy is remedied. However, previous demonstrations of this remediation have provided very explicit task-related information and it can be questioned whether it is trivial that such information leads to more correct judgments. The primary aim of this study was to test the nested- sets hypothesis in two different formats of a probability judgment task, by more subtly hinting about the nested-set structure. Twenty-nine participants were randomly divided into two groups, one Probability condition and one Informed probability condition, where participants in the latter condition were provided with the hint. The second aim was to investigate whether the Informed probability condition was performed more slowly, potentially due to the time-cost of more elaborated judgments. The results show that a subtle hint about the nested-set structure was able to remedy the conjunction fallacy in a forced-choice probability judgment task but not statistically reliably in a probability estimation task. No response-time differences were observed between the conditions. The results support the nested-sets hypothesis and imply that even a subtle reasoning hint clarifying the relation between categories and subcategories might remedy one of the most robust probability judgment fallacies. / Människor är i allmänhet dåliga på att göra bedömningar som följer principer för sannolikhetsteori. En indikation på det är ”konjunktionsfelet”: att bedöma en konjunktion (A&B) som mer sannolik än sin konstituent (A). Konjunktionsfelet har påvisats i flera studier på sannolikhetsbedömningar. Olika sätt att avhjälpa felet har föreslagits. Enligt nested-set hypotesen föreslås att när nested-set strukturen av ett problem blir tydlig (dvs. relationen mellan kategorier och subkategorier), minskas benägenheten att begå konjunktionsfelet. Däremot har tidigare demonstrationer av den här minskningen angett väldigt explicit uppgifts-relaterad information och det kan ifrågasättas om det är trivialt att sådan information leder till mer korrekta bedömningar. Studiens primära syfte var att testa nested-set hypotesen i två olika sannolikhetsbedömningsformat, genom att subtilt antyda om nested-set strukturen. Tjugonio deltagare delades slumpmässigt in i två grupper, en Sannolikhetsbetingelse och en Informerad sannolikhetsbetingelse, där den senare betingelsen fick den extra informationen. Det andra syftet var att undersöka om Informerad sannolikhetsbetingelsen skulle utföras långsammare, potentiellt på grund av tids-kostnaden av mer elaborerade bedömningar. Resultatet visar att en subtil antydan om nested-set strukturen minskade konjunktionsfelet i en fler-vals uppgift på sannolikhetsbedömningar men inte statistiskt pålitligt i en sannolikhetsestimeringsuppgift. Inga responstidsskillnader hittades mellan betingelserna. Resultat stödjer nested-set hypotesen och antyder att även en subtil antydan som klargör relationen mellan kategorier och underkategorier kan åtgärda ett av de mest robusta tankefel som observerats vid sannolikhetsbedömningar.

Humans repeatedly commit the so called “conjunction fallacy”, erroneously judging the probability of two events occurring together as higher than the probability of one of the events. Certain hints have been shown to mitigate this tendency. The present thesis investigated the relations between three psychological factors and performance on conjunction tasks after reading such a hint. The factors represent the understanding of probability and statistics (statistical numeracy), the ability to resist intuitive but incorrect conclusions (cognitive reflection), and the willingness to engage in, and enjoyment of, analytical thinking (need-for-cognition). Participants (n = 50) answered 30 short conjunction tasks and three psychological scales. A bimodal response distribution motivated dichotomization of performance scores. Need-for-cognition was significantly, positively correlated with performance, while numeracy and cognitive reflection were not. The results suggest that the willingness to engage in, and enjoyment of, analytical thinking plays an important role for the capacity to avoid the conjunction fallacy after taking a hint. The hint further seems to neutralize differences in performance otherwise predicted by statistical numeracy and cognitive reflection. / Människor begår ofta det så kallade ”konjuktionsfelslutet”, genom att felaktigt bedöma sannolikheten för sammanträffandet av två händelser som större än sannolikheten för en av händelserna. Vissa typer av ledtrådar har visat sig mildra denna tendens. Denna uppsats undersökte relationerna mellan tre psykologiska faktorer och prestation på konjunktionsuppgifter efter att ha läst en sådan ledtråd. Faktorerna motsvarade förståelsen för sannolikhet och statistik (statistisk räknefärdighet, eng., statistical numeracy), förmågan att motstå intuitiva men felaktiga slutsatser, (kognitiv reflektion, eng., cognitive reflection), samt viljan och lusten till analytiskt tänkande (behov-av-tänkande, eng., need-for-cognition). Deltagare (n = 50) besvarade 30 korta konjunktionsuppgifter och tre psykologiska mätskalor. En bimodal svarsfördelning motiverade dikotomisering av resultaten. Behov-av-tänkande var signifikant, positivt korrelerat med prestation, vilket varken räknefärdighet eller kognitiv reflektion var. Resultaten tyder på att viljan och lusten till analytiskt tänkande spelar en viktig roll i förmågan att undvika konjunktionsfelslutet efter att ha fått en ledtråd. Ledtråden verkar också neutralisera skillnader i prestation som annars uppstår på grund av räknefärdighet och kognitiv reflektion.

Over the last few years, public transportation has become more desirable as capacity of existing roadways failed to keep up with rapidly increasing traffic demand. Buses are one of the most common modes of public transportation with low impact on network capacity, especially in small and congested urban areas. However, the use of regularly scheduled buses as the main public transport mode can become useless with the presence of traffic congestion and dense construction areas. In cases like these, innovative solutions, such as bus rapid transit (BRT), can provide an increased level of service without having to resort to other, more expensive modes, such as light rail transit (LRT) and metro systems (subways). Transit signal priority (TSP), which provides priority to approaching buses at signalized intersections by extending the green or truncating the red, can also increase the performance of the bus service. Understanding the combined impact of TSP and BRT on network traffic operations can be complex. Although TSP has been implemented worldwide, none of the previous studies have examined in depth the effects of using conditional and unconditional TSP strategies with a BRT system. The objective of this research is to evaluate the effectiveness of BRT without TSP, then with conditional or unconditional TSP strategies. The micro-simulation software VISSIM was used to compare different TSP and BRT scenarios. These simulation scenarios include the base scenario (before implementation of the TSP and BRT systems), Unconditional TSP (TSP activates for all buses), Conditional TSP 3 minutes behind (TSP only activates for buses that are 3 minutes or more behind schedule), Conditional TSP 5 minutes behind (only activates for buses 5 minutes or more behind schedule), BRT with no TSP, BRT with Unconditional TSP, BRT with Conditional TSP 3 minutes behind, and BRT with Conditional TSP 5 minutes behind. The VISSIM simulation model was developed, calibrated and validated using a variety of data that was collected in the field. These data included geometric data, (number of lanes, intersection geometries, etc.); traffic data (average daily traffic volumes at major intersections, turning movement percentages at intersections, heavy vehicle percentages, bus passenger data, etc.); and traffic control data (signal types, timings and phasings, split history, etc.). Using this field data ensured the simulation model was sufficient for modeling the test corridor. From this model, the main performance parameters (for all vehicles and for buses only) for through movements in both directions (eastbound and westbound) along the corridor were analyzed for the various BRT/TSP scenarios. These parameters included average travel times, average speed profiles, average delays, and average number of stops. As part of a holistic approach, the effects of BRT and TSP on crossing street delay were also evaluated. Simulation results showed that TSP and BRT scenarios were effective in reducing travel times (up to 26 %) and delays (up to 64%), as well as increasing the speed (up to 47%), compared to the base scenario. The most effective scenarios were achieved by combining BRT and TSP. Results also showed that BRT with Conditional TSP 3 minutes behind significantly improved travel times (17 – 26%), average speed (30 – 39%), and average total delay per vehicle (11 – 32%) for the main corridor through movements compared with the base scenario, with only minor effects on crossing street delays. BRT with Unconditional TSP resulted in significant crossing street delays, especially at major intersections with high traffic demand, which indicates that this scenario is impractical for implementation in the corridor. Additionally, BRT with Conditional TSP 3 minutes behind had better travel time savings than BRT with Conditional TSP 5 minutes behind for both travel directions, making this the most beneficial scenario. This research provided an innovative approach by using nested sets (hierarchical design) of TSP and BRT combination scenarios. Coupled with microscopic simulation, nested sets in the hierarchical design are used to evaluate the effectiveness of BRT without TSP, then with conditional or unconditional TSP strategies. The robust methodology developed in this research can be applied to any corridor to understand the combined TSP and BRT effects on traffic performance. Presenting the results in an organized fashion like this can be helpful in decision making. This research investigated the effects of BRT along I-Drive corridor (before and after conditions) at the intersection level. Intersection analysis demonstrated based on real life data for the before and after the construction of BRT using the Highway Capacity SoftwareTM (HCS2010) that was built based on the Highway Capacity Manual (HCM 2010) procedures for urban streets and signalized intersections. The performance measure used in this analysis is the level of service (LOS) criteria which depends on the control delay (seconds per vehicle) for each approach and for the entire intersection. The results show that implementing BRT did not change the LOS. However, the control delay has improved at most of the intersections' approaches. The majority of intersections operated with an overall LOS "C" or better except for Kirkman Road intersection (T2) with LOS "E" because it has the highest traffic volumes before and after BRT construction. This research also used regression analysis to observe the effect of the tested scenarios analyzed in VISSIM software compared to the No TSP – No BRT base model for all vehicles and for buses only. The developed regression model can predict the effect of each scenario on each studied Measures of Performance (MOE). Minitab statistical software was used to conduct this multiple regression analysis. The developed models with real life data input are able to predict how proposed enhancements change the studied MOEs. The BRT models presented in this research can be used for further sensitivity analysis on a larger regional network in the upcoming regional expansion of the transit system in Central Florida. Since this research demonstrated the operational functionality and effectiveness of BRT and TSP systems in this critical corridor in Central Florida, these systems' accomplishments can be expanded throughout the state of Florida to provide greater benefits to transit passengers. Furthermore, to demonstrate the methodology developed in this research, it is applied to a test corridor along International Drive (I-Drive) in Orlando, Florida. This corridor is key for regional economic prosperity of Central Florida and the novel approach developed in this dissertation can be expanded to other transit systems.

Den här studien syftade till att undersöka om mental arbetsbelastning kan påverka benägenhetenatt begå konjunktionsfelet vid sannolikhetsbedömningar, trots att man fått ledtrådarsom synliggjort konjunktionsregeln. Detta undersöktes med en experimentell mellangruppsdesign.I studien deltog 57 deltagare, varav 27 i experimentgruppen och 30 i kontrollgruppen.Deltagarna var i huvudsak studenter på universitetsnivå. Grupperna hade en jämn könsfördelning.Vad gäller ålder så var medelvärdet i kontrollgruppen 24.8 och medelvärdet i experimentgruppenvar 30.7. Samtliga deltagare fick utföra ett datorbaserat test. Båda gruppernastest bestod av sannolikhetsbedömningsuppgifter, felstavningsuppgifter, samt en tilläggsuppgiftdär deltagarna ombads ange om ett visst ord förekommit i tidigare fråga eller ej. Experimentbetingelseninnehöll dessutom en visuospatial arbetsminnesuppgift. Resultatet visade attmental arbetsbelastning inte ökade antalet konjunktionsfel vid sannolikhetsbedömningar dådeltagarna fått ledtrådar som synliggjort konjunktionsregeln. Slutsatsen visar att det inte behövervara mer resurskrävande för arbetsminnet att göra normativa bedömningar och att tillgodogörandetav konjunktionsregeln är robust mot mental arbetsbelastning. Framtida forskningskulle kunna undersöka vilken betydelse ett visst antal ledtrådar har för om tillgodogörandetav konjunktionsregeln påverkas av mental arbetsbelastning. / The aim of this study was to investigate whether mental workload can affect the tendency tocommit the conjunction fallacy in probability assessments, despite having read clues that exposethe conjunction rule. This was investigated with an experimental between-group design.In total, the study had 57 participants, whereof 27 in the experiment group and 30 in the controlgroup. The groups were equally balanced concerning sex. The average age in the controlgroup was 24.8 years compared to 30.7 years in the experiment group. All participants performeda computer-based test. Both groups’ test consisted of tasks with probability assessments,discovering misspelled words and an additional task about estimating whether a certainword had occurred during the previous task. The experimental condition also consisted ofa visuo-spatial working memory task. The result indicated that mental workload did not increasethe number of conjunction fallacies committed in probability assessments, given thatthe participants had read clues that expose the conjunction rule. From this result, the conclusionis drawn that normative judgments are not necessarily more demanding for the workingmemory, also that the utilization of the conjunction rule is resistant to mental workload. Futureresearch might investigate what impact a certain number of clues has for whether theutilization of the conjunction rule is affected by mental work load.