Waiting Tolerance: Ramp Delay vs. Freeway Congestion

Waiting tolerance at ramp meters and travel time on the freewaywere measured using a computer administered stated preference (CASP) survey and a virtual experience stated preference (VESP) methodemploying a driving simulator.The selections varied in the number of minutes waiting at a ramp meter with vehicle speed once on the freeway. The subjects ranked the selections in order of preference. The results were statistically analyzed using a binary logit model controlling for demographics, socioeconomic characteristics, daily travel time, and personality scores.The results by the CASP method displayed a preference for freeway congestion to ramp delay, but opposite results were obtained by the VESP method. A number of reasons are posited to explain the difference, but the results indicate that method of stated preference data collection can significantly affect conclusions drawn.Ramp meters; Personality; Stated preference; Driving simulator; Travel time

Weighting Waiting: Evaluating the Perception of In-Vehicle Travel Time Under Moving and Stopped Conditions

This paper describes experiments comparing traditional computer administered stated preference with virtual experience stated preference to ascertain how people value stopped delay compared with stop-and- go or freeflow traffic. The virtual experience stated preference experiments were conducted using a wrap around driving simulator. The two methods produced two different results, with the traditional computer assisted stated preference suggesting that ramp delay is 1.6 Ð 1.7 times more onerous than freeway time, while the driving simulator based virtual experience stated preference suggested that freeway delay is more onerous than ramp delay. Several reasons are hypothesized to explain the differences, including recency, simultaneous versus sequential comparison, awareness of public opinion, the intensity of the stop-and-go traffic, and the fact that driving in the real-world is a goal directed activity. However without further research, which, if any, of these will eventually prove to be the reason is unclear. What is clear is that a comparison of the computer administered stated preference with virtual experience stated preference produces different results, even though both procedures strive to find the same answers in nominally identical sets of conditions. Because people experience the world subjectively, and make decisions based on those subjective experiences, future research should be aimed at better understanding the differences between these subjective methodologies.transportation, travel behavior, driving simulator, ramp meters

The traffic and behavioral effects of the I-35W Mississippi River bridge collapse

The collapse, on August 1, 2007, of the I-35W bridge over the Mississippi River in Minneapolis, abruptly interrupted the usual route of about 140,000 daily vehicle trips and substantially disturbed the ßow pattern on the network. It took several weeks for the network to re-equilibrate, during which period, travelers continued to learn and adjust their travel decisions. A good understanding of this process is crucial for traffic management and designing mitigation schemes. A survey collected behavioral responses to the bridge collapse. Traffic data were also collected to understand the traffic conditions experienced by road users. Data from both resources are analyzed and compared. Findings of behavioral effects of capacity changes could have significant implications for travel demand modeling, especially of day-to-day travel demandMinnesota, Minneapolis, I-35W bridge collapse, travel behavior, travel survey

Flagger Operations: Investigating Their Effectiveness in Capturing Driver Attention

This two-pronged (driving simulation and field study) investigation of driver behavior in work zones contributes basic and applied knowledge to our understanding of work zone safety. In the driving simulator study, a fully interactive PC-based STISIM driving simulator was used to test the effectiveness of roadway elements designed to capture and sustain the attention of drivers in flagger-operated work zones. The participants were 160 licensed drivers from four age groups: 18-24, 32-47, 55-65, and 70+ years of age. Each participant drove each of the three conditions in counterbalanced order. The driving simulator study revealed that the new set of elements is more effective than the elements currently used to reduce driving speeds on the approach to a flagger-controlled work zone. No difference in mean driver speed was found in response to the sign with an LED presence. The dynamic speed display coupled with the horn is more effective than the dynamic speed display alone. The cognitively engaging elements identified as effective in the driving simulator study were tested in two field operational tests. The field tests revealed that all but one of the elements identified in the experimental driving simulator study were effective. In particular, the findings revealed that a combination of the speed trailer and horn barrel are effective in reducing the overall speed of vehicles approaching the field study work zone. The field test revealed that the new experimental layout practically eliminated high-speed outliers in addition to its success in reducing driver approach speed to the flag operator

Value of Travel-Time Reliability: Commuters’ Route-Choice Behavior in the Twin Cities

Travel-time variability is a noteworthy factor in network performance. It measures the temporal uncertainty experienced by users in their movement between any two nodes in a network. The importance of the time variance depends on the penalties incurred by the users. In road networks, travelers consider the existence of this journey uncertainty in their selection of routes. This choice process takes into account travel-time variability and other characteristics of the travelers and the road network. In this complex behavioral response, a feasible decision is spawned based on not only the amalgamation of attributes, but also on the experience travelers incurred from previous situations. Over the past several years, the analysis of these behavioral responses (travelers’ route choices) to fluctuations in travel-time variability has become a central topic in transportation research. These have generally been based on theoretical approaches built upon Wardropian equilibrium, or empirical formulations using Random Utility Theory. This report focuses on the travel behavior of commuters using Interstate 394 (I-394) and the swapping (bridge) choice behavior of commuters crossing the Mississippi River in Minneapolis. The inferences of this report are based on collected Global Positioning System (GPS) tracking data and accompanying surveys. Furthermore, it also employs two distinct approaches (estimation of Value of Reliability [VOR] and econometric modeling with travelers’ intrapersonal data) in order to analyze the behavioral responses of two distinct sets of subjects in the Minneapolis-Saint Paul (Twin Cities) area

GeneChip analyses point to novel pathogenetic mechanisms in mantle cell lymphoma

The translocation t(11;14)(q13;q32) is the genetic hallmark of mantle cell lymphoma (MCL) but is not sufficient for inducing lymphomagenesis. Here we performed genome-wide 100K GeneChip Mapping in 26 t(11;14)-positive MCL and six MCL cell lines. Partial uniparental disomy (pUPD) was shown to be a recurrent chromosomal event not only in MCL cell lines but also in primary MCL. Remarkably, pUPD affected recurrent targets of deletion like 11q, 13q and 17p. Moreover, we identified 12 novel regions of recurrent gain and loss as well as 12 high-level amplifications and eight homozygously deleted regions hitherto undescribed in MCL. Interestingly, GeneChip analyses identified different genes, encoding proteins involved in microtubule dynamics, such as MAP2, MAP6 and TP53, as targets for chromosomal aberration in MCL. Further investigation, including mutation analyses, fluorescence in situ hybridisation as well as epigenetic and expression studies, revealed additional aberrations frequently affecting these genes. In total, 19 of 20 MCL cases, which were subjected to genetic and epigenetic analyses, and five of six MCL cell lines harboured at least one aberration in MAP2, MAP6 or TP53. These findings provide evidence that alterations of microtubule dynamics might be one of the critical events in MCL lymphomagenesis contributing to chromosomal instability

A principal component meta-analysis on multiple anthropometric traits identifies novel loci for body shape

Large consortia have revealed hundreds of genetic loci associated with anthropometric traits, one trait at a time. We examined whether genetic variants affect body shape as a composite phenotype that is represented by a combination of anthropometric traits. We developed an approach that calculates averaged PCs (AvPCs) representing body shape derived from six anthropometric traits (body mass index, height, weight, waist and hip circumference, waist-to-hip ratio). The first four AvPCs explain >99% of the variability, are heritable, and associate with cardiometabolic outcomes. We performed genome-wide association analyses for each body shape composite phenotype across 65 studies and meta-analysed summary statistics. We identify six novel loci: LEMD2 and CD47 for AvPC1, RPS6KA5/C14orf159 and GANAB for AvPC3, and ARL15 and ANP32 for AvPC4. Our findings highlight the value of using multiple traits to define complex phenotypes for discovery, which are not captured by single-trait analyses, and may shed light onto new pathways

A principal component meta-analysis on multiple anthropometric traits identifies novel loci for body shape

Large consortia have revealed hundreds of genetic loci associated with anthropometric traits, one trait at a time. We examined whether genetic variants affect body shape as a composite phenotype that is represented by a combination of anthropometric traits. We developed an approach that calculates averaged PCs (AvPCs) representing body shape derived from six anthropometric traits (body mass index, height, weight, waist and hip circumference, waist-to-hip ratio). The first four AvPCs explain >99% of the variability, are heritable, and associate with cardiometabolic outcomes. We performed genome-wide association analyses for each body shape composite phenotype across 65 studies and meta-analysed summary statistics. We identify six novel loci: LEMD2 and CD47 for AvPC1, RPS6KA5/C14orf159 and GANAB for AvPC3, and ARL15 and ANP32 for AvPC4. Our findings highlight the value of using multiple traits to define complex phenotypes for discovery, which are not captured by single-trait analyses, and may shed light onto new pathways.Peer reviewe