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Bacterial flagella and type IV pili (TFP) are surface appendages that enable motility and mechanosensing through distinct mechanisms. These structures were previously thought to have no components in common. Here, we report that TFP and some flagella share proteins PilO, PilN, and PilM, which we identified as part of the Helicobacter pylori flagellar motor. H. pylori mutants lacking PilO or PilN migrated better than wild type in semisolid agar because they continued swimming rather than aggregated into microcolonies, mimicking the TFP-regulated surface response. Like their TFP homologs, flagellar PilO/PilN heterodimers formed a peripheral cage that encircled the flagellar motor. These results indicate that PilO and PilN act similarly in flagella and TFP by differentially regulating motility and microcolony formation when bacteria encounter surfaces.

PurposeAtaxia-Telangiectasia Mutated (ATM) has been implicated in the risk of several cancers, but establishing a causal relationship is often challenging. Although ATM single-nucleotide polymorphisms have been linked to melanoma, few functional alleles have been identified. Therefore, ATM impact on melanoma predisposition is unclear.MethodsFrom 22 American, Australian, and European sites, we collected 2,104 familial, multiple primary (MPM), and sporadic melanoma cases who underwent ATM genotyping via panel, exome, or genome sequencing, and compared the allele frequency (AF) of selected ATM variants classified as loss-of-function (LOF) and variants of uncertain significance (VUS) between this cohort and the gnomAD non-Finnish European (NFE) data set.ResultsLOF variants were more represented in our study cohort than in gnomAD NFE, both in all (AF = 0.005 and 0.002, OR = 2.6, 95% CI = 1.56-4.11, p

Caltrans has recently funded a project, through the Mineta Transportation Institute (MTI) at San Jose State University, about geometric and performance feasibility of using virtually only one dedicated but dynamically reversible lane to provide two-way Bus Rapid Transit (BRT) or light-rail services at the same or similar service levels as those achievable with two dedicated lanes, along the median of a busy commute corridor with at-grade crossings and regular provision of left-turn lanes. This project extended that deterministic performance study in four complementary directions. We (i) developed two episodes of simulation/animation to facilitate understanding key ideas of the concept, (ii) addressed the “backward-compatibility” issue, (iii) developed speed control rules to absorb the impact of the stochastic demand (and the different distances between pairs of neighboring stops) on the performance of a closed system, and (iv) developed speed control rules and transit-signal-priority rules for an open system to ensure a green signal for all transit vehicles at any intersection. We believe that the next step in this line of research is to work on, simultaneously, deployment issues with city and transportation planners, acceptance issues with transit users, automobile drivers, other stakeholders (including the general public), design issues for actual deployment sites (based on inputs provided by the planners, transit users, automobile drivers and other stakeholders), and development of site-specific and high-fidelity study tools.

Traffic congestion will continue to worsen and likely worsen at a faster rate than ever. People throughput and freight throughput have become critical issues for California and the rest of the nation. PATH has funded with approximately $125K a research project entitled "Evaluation of Bus and Truck Automation Scenarios" jointly proposed by Jan Botha (Principal Investigator) of Department of Civil and Environmental Engineering and Jacob Tsao (Co-PI) of Department of Industrial and Systems Engineering at San Jose State University. This report summarizes the major findings of the research conducted by Professor Tsao and his assistants with approximately $44K out of the overall funding of $125K for the project; the infrastructure and other aspects of the research are reported by Jan Botha separately.

Traffic congestion will continue to worsen and likely worsen at a faster rate than ever. People throughput and freight throughput have become critical issues for California and the rest of the nation. PATH has been funding a one-year research project entitled "Definition and Evaluation of Bus and Truck Automation Operations Concepts," proposed by the authors. This report summarizes the results of the research project achieved during the first six months. During those six months, we reviewed literature and developed operating concepts for both urban bus automation and inter-city truck automation. We also selected a small number of most promising operating concepts for urban bus automation and inter-city truck automation, both with variations and intermediate deployment steps. On urban bus automation, we selected one unprotected automated busway system (ABUS) for city operations and two operating concepts for automated bus operations on or along a freeway. All or a subset of these three concepts can be integrated to form other operating concepts. On truck automation, we selected an operating concept for a protected inter-city truck-AHS. These concepts describe how automated systems involving buses or trucks operate as a system and how they interact with the surrounding transportation systems. These systems, if implemented, will revolutionize the current bus or truck transportation systems. They certainly cannot be achieved suddenly, and hence can be regarded as end-state systems. Since these end-state operating concepts re intended for real-world implementation and such implementation requires the participation of many stakeholders, any creditable end-state operating concept must be accompanied by and even justified with credible deployment sequences. We developed deployment sequences for these operating concepts to demonstrate the deployability of these concepts and to explain how to "get there from here."

This research has four main purposes: 1. Investigate and suggest how the public sector in the state of California (including the state, cities, counties, airports, etc.) can assist the air cargo industry in providing more efficient services to businesses and the general public of California. 2. Learn from the air cargo industry's efficient intermodal operations about intermodal freight and passenger transportation in general. 3. Learn from the industry's technology deployment efforts for the purpose of developing strategies for deploying Intelligent Transportation Systems (ITS) technologies in the general freight industry and in the overall transportation industry. 4. Suggest ITS deployment strategies for other segments of the freight industry.

Traffic congestion has been a pervasive problem in many urban areas of this country. This paper studies the potential of carpooling among unrelated partners (i.e., inter-household carpooling) for demand reduction during peak commute hours. Basic questions about this potential include the following. Can the current population density, origin-destination distribution, tolerable pick-up and drop-off delays, departure time distribution, and the tolerance for deviation from preferred departure time support a sizable carpooling population that can make a significant contribution to traffic demand reduction? Could the proportion of long trips that are likely candidates for carpooling (e.g., those long trips with same O-D) be so small that no significant traffic demand reduction could be expected from carpooling? The potential depends on many factors, some of which are more amenable to quantification than others. Our approach to assessing the potential is to separate such quantifiable factors from the rest, and then, based on these quantifiable factors, identify likely upper bounds for the potential. This paper focuses on a simplified urban sprawl in which the densities of workers and jobs are uniform over an infinitely large flat geographical area. For our numerical study, we use the job and worker data of the city of Los Angeles to approximate the worker/job density. An entropy optimization model that is equivalent to the gravity model is used for trip distribution. Under the assumptions made in the paper, carpooling among unrelated partners has little potential for demand reduction. Key Words: Carpool, Demand Management, Urban Sprawl, Trip Distribution, Entropy Optimization

California would be the seventh largest economy in the world, if it were a nation. Efficient goods movement is crucial to California's economy. To support continued growth of the State's economy, Caltrans is leading the development of a Statewide Goods Movement Strategy. This strategy is being prepared as a response to a recommendation of the 1993 California Transportation Plan. It serves as one element, together with the Transportation System Performance Measures report being prepared in parallel by Caltrans, of the 1998 California Transportation Plan update. Air cargo consists predominantly of high-value, time-sensitive or time-definite goods, e.g., electronic equipment, emergency shipments, overnight packages, etc. Timely delivery of these goods has been an important element of many manufacturing and service operations in California. Therefore, the air cargo industry is a vital part of the State's economy. Continued ability of the State's air cargo industry to serve the other industries in the State and the State's ability to capitalize on the forecast growth of air cargo routes between Pacific-Rim countries in Asia and North America are essential to the prosperity of California. However, future demand on California's air cargo system may continue to outpace the future supply of the system's capacity. Faced with these challenges, Caltrans began a systematic investigation into the role of air cargo in California's goods movement, as part of the larger development effort for a statewide goods movement strategy, and funded a research project in 1997 for the Institute of Transportation Studies at U.C. Berkeley to (i) gain a broader understanding of the State's air cargo industry and the role of air cargo in California's goods movement, (ii) assess the importance of air cargo to the State's economy, (iii) begin identification of issues hindering efficient air cargo movement in the State, and (iv) explore possible State roles for resolving the issues. This "white paper" documents the findings of that research and serves as an input to the development of the Statewide Goods Movement Strategy.

This report develops a probabilistic model for analyzing longitudinal collision/safety between an abruptly decelerating vehicle and its immediate follower on an Automated Highway System. The input parameters are the distance between the two vehicles, their common speed prior to the failure, the reaction delay of the following vehicle and a bivariate distribution for the two deceleration rates. The output includes the probability of a collision and the probability distribution of the relative speed at collision time. These safety consequences can be used to balance the desire to increase AHS capacity with the safety requirements.We use this model to compare the safety consequences associated with the platooning and "free-agent" longitudinal-separation rules. We also demonstrate that the free-agent rule implemented with a potential technology of fast and accurate emergency deceleration, under some reasonable conditions, can avoid collisions while offering a high freeway capacity previously thought possible only under the platooning rule. This model has many other applications.

Automated Highway Systems (AHS) have the potential for offering large capacity and safety gains without requiring significant amounts of additional right-of-way. Since the general public will be the users of the AHS, human factors must play a pivotal role in the research and development of AVCS technologies and AHS operation. In two companion reports, three attributes critical to AHS human factors were identified and seven scenarios featuring variations in these attributes proposed. To ensure the identification of all major compounding attribute combinations, detailed operational events, from the perspective of the driver, were identified. This paper focuses on failure events, where a failure event is defined to be the occurrence of a functional failure during a normal operational event.After briefly reviewing the seven "first-generation'' scenarios, this report first describes the criteria for selecting the three "second-generation'' scenarios and then reports the selection result. While examining each of the normal operational events identified for the three scenarios, we identify possibly multiple major failure events by assuming the failure of one operational function at a time. Failure events resulting from the failure of multiple operational functions can be inferred. For each failure event, we also define possible failure consequences and possible system responses to resolve the failure event. These second-generation scenarios are selected for studying AHS human factors and are not being advocated by the authors as the better deployment choices among the seven first-generation scenarios, even from the human-factors point-of-view. Similarly, the responses provided for the major failure events are not being advocated as the better ones. Rather, to truly identify human capability in failure/emergency situations and not to rule out possible human abilities prematurely, we tend to stretchthe limit of human capability in the responses. The true human capability is a crucial subject for future investigation.

Automated Highway Systems (AHS) have the potential for offering large capacity and safety gains without requiring significant amounts of additional right-of-way. Since the general public will be the users of the AHS, human factors must play a pivotal role in the research and development of AVCS technologies and AHS operation. This paper focuses on fully automated AHS.To ensure the identification of all major human factors issues, we have identified major options for operating fully automated AHS. These options are categorized in the following four dimensions: separation of traffic, transitions between manual and automated driving, normal automated driving and emergency response. Attributes critical to AHS human factors include (i) possible isolation of automated traffic from the manual traffic, (ii) possible separations among automated traffic by lane barriers, and (iii) the vehicle-following rule. We propose six scenarios featuring variations in these attributes. To ensure the identification of all major compounding attribute combinations, detailed operational events, from the perspective of the driver, are identified. The AHS scenarios proposed in this paper are designed for the study of human factors in fully automated AHS. Further scrutiny into these scenarios is required for other studies.

What some human drivers have done wrong has been blamed for much of the problem associated with the current highway systems. For example, driver inattention, fatigue and other human errors have often been cited as major sources of safety hazard on current highways and human capabilities as major limitations on current highway capacity. Such human deficiencies and the pervasive urban traffic congestion have motivated the concept of Automated Highway Systems (AHS). The fundamental objective of AHS is to achieve user and societal benefits through replacing human driving by automated machine driving. The first fundamental thesis of this paper is that safe replacement of human driving on highways by automation requires a rigorous examination into what most human drivers have been doing right on the current highway systems. Such an examination would provide much insight into the functional requirements for AHS, i.e., what machines must do to emulate or improve human driving. Furthermore, what human drivers tend to do poorly or well must be contrasted with what machines tend to do well or poorly. A complementary arrangement must be sought if the machines cannot safely or affordably replace driver intelligence for highway driving, either on a mature AHS or during intermediate stages toward it.Driving tasks involved in any vehicle-roadway system depend on the driving environment. For example, city-street driving is different from driving on current highways and AHS driving may be drastically different from current highway driving. On an AHS, any human intelligence required by current highway driving must be replaced (emulated or improved) by machine intelligence or continues to be provided by the driver, if proven safe, unless the corresponding tasks are eliminated from AHS driving due to the environment change. Note that new driving environments may introduce new driving tasks. Since the driving environment during early deployment stages of AHS is likely identical to that of the current highways, most, if not all, of the current highway-driving tasks remain necessary. The second fundamental thesis of this paper is that current highway driving involves not only many routine chores, which machines tend to do well, but also much human intelligence, which machines tend to do poorly. Such intelligence is often required in subtle ways or is required only when unusual but normal events occur. We identify many such driving functions. If some of these required functions cannot be safely emulated by machines either in a mature end-state AHS or during intermediate stages toward the end state, then "driver-in-the-loop'' must not be ruled out at the current research and development stage.

This paper proposes an approach to defining evolutionary scenarios for the deployment of an Automated Highway System (AHS). Six dimensions of deployment difficulties are identified: technology, infrastructure, human factors, vehicle manufacturing and maintenance, insurance, and public will.

This paper proposes a shuttle van service as the initial deployment Automated Highway System (AHS) target. The freeway portion of the trip is fully automated and a professional driver is required for off-freeway driving. Advantages from the viewpoint of of different deployment issues are discussed. Focus is on the concept definition.

Dynamic traffic assignment through analytical modeling and optimization has been widely accepted by the IVHS R&D community as a promising traffic control tool for understanding and relieving traffic congestion on conventional highways and city streets. Due to the completely controlled nature of AHS traffic, dynamic assignment of AHS traffic is even more promising. One added dimension of complexity associated with AHS dynamic traffic assignment is lane assignment.  Lane changes, for fully utilizing AHS capacity or for exiting, incur disturbances to and hence reduction of longitudinal flow. Intelligent lane assignment is necessary to ensure a high rate of successful exiting, to another highway or to city streets, while minimizing the disturbances to the longitudinal flow. Merging maneuvers occurring at merge points such as on-ramps, highway-to-highway interchanges and locations where one lane is being dropped may also introduce disturbances to the longitudinal traffic flow on AHS. Intelligent metering and flow control at on-ramps and other merge locations is necessary to maximize the capacity while balancing the need to serve local demands with the need to optimize system throughput. This paper identifies a general class of equations/inequalities to represent the impact of lane changes and merges on AHS longitudinal flow and develop mathematical models for system-optimal dynamic traffic assignment on a two-lane (one direction) automated highway. The amount of impedance to the longitudinal flow depends on the operating scenario and traffic conditions and can be highly stochastic. This paper focuses on deterministic impedance. This is a necessary step towards a complete study of stochastic impedance and the experience gained with the proposed focus is indispensable for studying the stochastic impedance.

This paper provides a preliminary assessment of uncertainties, both technical and institutional, associated with the deployment of Automated Highway Systems (AHS). Seven issues are addressed, concerning whether: (1) People use AHS, ( 2 ) Auto makers manufacture equipped vehicles, (3) Government builds AHS roadways, (4)Highways can evolve, ( 5 ) Interest groups do not obstruct, (6) Performance is adequate, and (7) Technology is feasible. For each issue, a table is provided that lists some of the more critical uncertainties.

In this paper, the authors study the capacity of key Automated Highway Systems (AHS) operating scenarios. The effect of the lane-flow rule, platooning or free-agent, as well as the lane barriers, on AHS capacity are studied. Special attention is paid to the interaction between the lane-flow rule and the lane change requirement. The paper consists of two major components, analytical models and AHS simulation. After a brief introduction of AHS operating strategies, analytical models are developed for general AHS. For simulation, the authors focus on a segregated AHS that has one automated lane and one transition lane.

This report defines an architecture for Automated Highway System (AHS) capacity-optimizing traffic planning functions. It identifies major traffic planning functions useful for optimizing the capacity of one or more major AHS operating scenarios and organizes them in a robust architecture that is modular, hierarchical, complete, expandable and integratable.

This paper develops a probabilistic model and a software tool for analyzing longitudinal collision/safety between two automated vehicles. The input parameters are the length of the gap between the two vehicles, the common speed prior to failure, the reaction delay of the following vehicle and a bivariate joint distribution of the deceleration rates of the two vehicles. The output includes the probability of a collision and also the probability distribution of the relative speed at collision time. The model is used to compare the safety consequences associated with the platooning and "free-agent" vehicle-following rules. Additionally, it is demonstrated that the free-agent vehicle-following rule implemented with a potential technology of fast and accurate emergency deceleration, under some reasonable conditions, can virtually avoid collisions while offering a high freeway capacity previously through possible only under the platooning rule.