bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance Analysis of Ultrathin Whitetopping Intersections on US-169: Elk River, Minnesota
Authors: Vandenbossche Julie M.
Published: April 2007

The Minnesota Department of Transportation constructed an ultrathin whitetopping (UTW) project at three consecutive intersections on US-169 at Elk River, Minnesota, to gain more experience with both the design and the performance of UTW. Distinct cracking patterns developed within each test section. The UTW test sections with a 1.2- ×1.2-m (4- ×4-ft) joint pattern included corner breaks and transverse cracks. Corner breaks were the primary distress in the test section with a 1.8- ×1.8-m (6- ×6-ft) joint pattern, although very little cracking was exhibited. The Minnesota Road Research Facility UTW test sections on I-94 allow comparisons of the same UTW design on hot-mix asphalt (HMA) pavements with different structural capacities to be made. The strain and deflection measurements emphasize the importance of the support provided by the HMA layer. A reduction in this support occurs when the temperature of the HMA is increased or when the HMA begins to ravel. During evaluations of whether UTW is a viable rehabilitation alternative, cores should be pulled from the pavement to determine if the asphalt is stripping and if the asphalt layer has adequate thickness. UTW can be successfully placed on as little as 76 mm (3 in.) of asphalt, if the quality of the asphalt is good. The cores should also reveal whether the asphalt layer is of uniform thickness and whether stripping and raveling have occurred. If the asphalt layer is of uniform thickness and stripping and raveling have not occurred, UTW is a good option for use in the rehabilitation of asphalt pavements.
Pennsylvania SPS-6 Performance at 10 Years: Evaluation of Concrete Pavement Rehabilitation Strategies
Authors: Morian Dennis A. , Coleman Laura , Frith Doug J. , Stoffels Shelley M. , Dawood Dan
Published: April 2007

With a long history of constructing jointed concrete pavements, Pennsylvania pursued the construction of Special Pavement Studies (SPS-6) sections for the rehabilitation of jointed concrete pavements experiment. After 10 years of service under very high loads on rural Interstate highways, a number of sections required renewal. The performances of the eight standard Strategic Highway Research Program sections, a control section, and three state supplemental sections were examined. The experiment included a broad range of treatments, including minimum and maximum concrete pavement restoration, the use of thin and thick overlays, and the use of crack or break and seat as well as rubblization as pretreatments for pavement overlays. Ten years after construction, many of the pavements that received the treatments are in need of major rehabilitation. This provides an opportune time to evaluate both the structural and functional performances of these test sections to date. Additionally, an evaluation of cost-effectiveness showed the importance of performing thorough evaluations of projects for rehabilitation and the potential benefit of rubblization of badly damaged jointed concrete pavements, a method used on the state supplemental sections, as a preoverlay strategy.
Performance of Flexible Pavement Maintenance Treatments in the Long-Term Pavement Performance SPS-3 Experiment
Authors: Hall Kathleen T. , Correa Carlos E. , Simpson Amy L.
Published: April 2007

A study was conducted to assess the relative performance of different flexible pavement maintenance treatments, including the influence of pretreatment condition and other factors. The data used in the study were drawn from the Long-Term Pavement Performance Studies' Specific Pavement Studies (SPS) SPS-3 experiment. The maintenance treatments used in the SPS-3 experiment are thin overlays, slurry seals, crack seals, and chip seals. The initial and long-term effects of the maintenance treatments on international roughness index (IRI), rutting, and cracking were analyzed, as were the influences of time, truck traffic, pretreatment condition, and climate. Thin overlays were found to be the most effective of the treatments studied, followed by chip seals and slurry seals. Crack sealing did not demonstrate any beneficial initial or long-term effect with respect to IRI, rutting, or cracking.
Early-Age Behavior of Concrete Overlays on Continuously Reinforced Concrete Pavements
Authors: Kim Seong-Min , Nelson Patricia Kim , Ruiz Mauricio , Rasmussen Robert Otto , Turner Dennis
Published: April 2007

Delamination is the primary mode of distress in most bonded concrete overlay (BCO) projects. The objective of the present study was to develop and calibrate a mechanistic delamination model to properly predict the early-age behavior of concrete overlays bonded to continuously reinforced concrete pavements (CRCPs). An experimental BCO on a CRCP section was constructed to monitor its behavior, and the field data were used to calibrate the mechanistic models. Two- and three-dimensional finite element models of the BCO on CRCPs were developed and calibrated. The results from the numerical analysis matched the experimental results well. Equations to predict the interfacial stresses at the corner of the composite structure by use of the two-dimensional finite element model were also developed. A sensitivity analysis was performed to investigate the effects of overlay and CRCP parameters, such as elastic modulus, thickness, coefficient of thermal expansion, and percent reinforcement, on the shear and interfacial normal stresses. This mechanistic model has been incorporated into the HIPERBOND (High-Performance Bonded Concrete Overlays) software developed for FHWA.
Mechanical Behavior of Ultrathin Whitetopping Structure Under Stationary and Moving Loads
Authors: Nishizawa Tatsuo , Murata Yoshiki , Kokubun Katsuro
Published: April 2007

The structural design of ultrathin whitetopping (UTW) requires precise predictions of the loading stresses in the concrete slabs. A plate finite element model (FEM) is not used for structures with UTW because the model is not able to account for the asphalt subbase behaviors and the mechanical interaction between the concrete slab and asphalt subbase. A three-dimensional FEM (3DFEM) was used for the stress calculation of UTW. To take into account the mechanical interaction at the interface between the concrete slab and asphalt subbase as well as the load transfer across the joint, a general interface element was developed and incorporated into 3DFEM. Also, the viscosities of asphalt materials were considered by the viscoelastic formulation in the 3DFEM. A loading test was conducted on a test pavement. Stationary and moving loads were applied to the concrete slabs, and the strains in the slabs and the asphalt subbase were measured. By comparing the strains computed by 3DFEM with the measured strains, it was found that the viscosity of the asphalt subbase and the interface condition significantly affect the stresses in the concrete slab.
Probabilistic Analysis of Highway Pavement Life for Illinois
Authors: Gharaibeh Nasir G. , Darter Michael I.
Published: April 2007

The Illinois Department of Transportation has periodically conducted pavement longevity studies to assess the longevities and the traffic loadcarrying capacities of these new and rehabilitated pavements so that any needed improvements to design, construction, or rehabilitation could be identified and implemented in a timely manner. The results of the latest round of pavement longevity studies in Illinois provide performance data updated through 2000 for new hot-mix asphalt concrete (HMAC), jointed reinforced concrete pavement (JRCP), and continuously reinforced concrete pavement (CRCP) construction as well as the asphalt concrete (AC) overlays (first, second, and third overlays) of these original pavements. These studies were conducted on more than 2,000 centerline miles of Interstate and other freeways that were constructed beginning in the 1950s in Illinois. Significant findings on the performance of the original pavements and overlays were obtained, and these findings will be of value to designers and managers to improve pavement cost-effectiveness and life. Survival curves have an economic impact on the agency. Key findings show the impact of pavement type (HMAC, JRCP, or CRCP), slab thickness, geographic location (north or south), durability cracking (D-cracking), and AC overlay thickness (coupled with preoverlay condition) on longevity and load-carrying capacity. The results of the probabilistic analysis illustrate the wide variation in pavement life and traffic carried. The study also provides models for predicting the probability of survival for various designs of original pavements and AC overlays in Illinois for use in pavement management.
Three-Dimensional Nonlinear Finite Element Model for Simulating Pavement Response: Study at Canterbury Accelerated Pavement Testing Indoor Facility, New Zealand
Authors: Saleh Mofreh F. , Steven Bruce , Alabaster David
Published: April 2007

A three-dimensional nonlinear finite element model (3D-FEM) was developed as part of a study of the effect of increasing axle load and tire pressure on pavement deterioration. The measured strains, interface stresses, and deflections were collected from the instrumented Canterbury Accelerated Pavement Testing Indoor Facility in New Zealand. In addition, two multilayer elastic models were used to compare the values from the finite element simulation and the actual measurements. The first elastic multilayer model was developed with ELSYM5 software, and the second model was developed with CIRCLY software. CIRCLY differs from ELSYM5 in the ability to account for material anisotropy; ELSYM5 considers the pavement materials to be isotropic. The actual strains and deformations were measured by Emu strain gauges embedded at different depths in the base and subgrade materials. Both the unbound granular base and the subgrade materials were modeled in 3D-FEM as elastic plastic materials. The results showed that for the unbound base layer, the strains calculated from the two elastic models were in reasonable agreement with the values measured in the instrumented test track, while the 3D-FEM model tended to overestimate the strains at the bottom of the base. While none of the models provided a perfect fit to the measured strains in the subgrade layer because the subgrade is less homogenous than assumed, 3D-FEM provided the closest fit. Also, CIRCLY provided better results than ELSYM5, which underestimated the displacement values compared with values obtained with CIRCLY and 3D-FEM.
Diversion from a Rural Work Zone with Traffic-Responsive Variable Message Signage System
Authors: Horowitz Alan J. , Weisser Ian , Notbohm Thomas
Published: April 2007

An experiment was made to determine the degree of alternative-route selection from a rural freeway that occurs because of implementation of a traffic-responsive variable message signage system in a work zone. The message signs gave real-time estimates of travel time to the end of the work zone. Alternative-route selection was measured through extensive volume counts on the freeway and on parallel arterial streets, both before and after implementation of the signage system. In addition, traffic volumes were measured at a variety of locations where alternativeroute selection was likely to occur and where it was unlikely to occur. Analysis of peak period data found that alternative-route selection rates were between 7% and 10% of the freeway traffic, depending on the location and the day of the week.
Theoretical Approach to Predicting Traffic Queues at Short-Term Work Zones on High-Volume Roadways in Urban Areas
Authors: Ullman Gerald L. , Dudek Conrad L.
Published: April 2007

A new theoretical approach is described that more accurately predicts the length of queues that will develop when one or more lanes are closed for short-term freeway road work in an urban area. A model was developed that represents the interactions between diversion and traffic queuing on the freeway. The model is based on macroscopic fluid-flow analogies of traffic and a new perspective of the freeway corridor as a section of permeable pipe. Historical traffic volumes on the roadway serve as the primary data input into the model. Unlike other work zone analysis methods, the model presents a rational representation of how traffic queues stabilize upstream of temporary work zone bottlenecks in urban areas. The model can be calibrated to reasonably represent the magnitude of traffic queues developing upstream of actual work zone lane closures on urban freeways in Texas.
Capturing Effects of Maintenance Practices in Highway Asset Valuation: Replacement-Cost Approach Versus Book-Value Method
Authors: Sirirangsi Poovadol , Amekudzi Adjo , Herabat Pannapa
Published: April 2007

The replacement-cost approach and the book-value method as decision support tools for selecting maintenance alternatives under budget constraints and for capturing the effects of maintenance practices on highway asset value are investigated. By using a case study based on the Thailand Pavement Management System, the replacement-cost approach and the book-value method are applied to analyze maintenance alternatives for selected highways. The versatility of these asset-valuation methods is explored for capturing trade-offs in the type and timing of maintenance and for incorporating the added value of effective maintenance practices and the impact of deferred maintenance in the overall asset value. The study demonstrated that the replacement-cost approach is a more versatile tool for considering the maintenance-related value of highways in maintenance decision making, whereas the book value may be a simpler financial accounting tool. The two approaches may be used together to clarify how maintenance expenditures are being translated into facility replacement value or how the overall value of the infrastructure is being preserved. The study results are potentially useful to agencies interested in capturing the added value of effective maintenance practices in the overall value of their asset base.
Case Study of Highway Maintenance Management: Ohio’s County Work Plans
Authors: Lozier William C. , Ellen Kimberlin Mary , Grant Robin
Published: April 2007

Maintaining the safety and mobility of the state highway network in a cost-effective manner is a top priority for any state department of transportation (DOT). As funding for major new infrastructure becomes scarce and traffic levels steadily rise, maximizing and maintaining the existing highway system becomes increasingly critical. For the Ohio DOT, the task of maintaining Ohio’s highways is massive. While only 35th in geographic size, the state of Ohio has the nation’s 5th-highest traffic volume traveling on the 4th-largest Interstate network and has the 2nd-largest bridge inventory. Traffic in Ohio has grown by 90% during the last 20 years, and this growth pattern is expected to continue. Ohio’s Interstate highways were built in the 1960s and have far exceeded their 20-year design life, creating an even greater need for effective highway maintenance. During the last 3 years, Ohio DOT adopted strategic initiatives to revamp the department’s maintenance management methods, improve practices, and optimize resource use. Focused on redefining, prioritizing, and tracking all maintenance resources, the department set out to combine planning, implementation, quality-review, and cost-accounting data into one manageable, easily accessed system. The product of this intensive effort, the Ohio DOT county annual work plans, is revolutionizing the way the department approaches maintenance management. Before the implementation of the work plans in July 2001, roadside conditions and maintenance efforts varied widely across the state. Following the inaugural year of the work plans, conditions were meeting statewide standards, reflecting the state’s new focus on more effectively managing Ohio’s transportation investment.
Performance Measures for Winter Operations
Authors: Adams Teresa M. , Danijarsa Mohamad , Martinelli Tom , Stanuch Gerald , Vonderohe Alan
Published: April 2007

New winter maintenance vehicles are being equipped with differential Global Positioning System (DGPS) receivers and numerous sensors that collect environmental data (e.g., pavement and air temperature), equipment status data (e.g., plow up, plow down), and material usage data (e.g., salt application rate). These data can be both telemetered to a dispatch center and recorded on magnetic media for later downloading. Data are transmitted and recorded as often as every 2 s. Such data, both type and quantity, have only recently become available. Vehicles were instrumented with the reasonable expectation that information can be used to improve winter maintenance. As a result, these technology demonstration projects tend to be guided by loosely defined “try-and-see” data requirements. Now, with the availability of these data, agencies are beginning to explore the possibilities for improving the performance of winter maintenance operations. A comprehensive set of performance measures for winter maintenance that can be computed from data collected by DGPS receivers and sensors on winter maintenance vehicles is described. The performance measures are indicators of how well winter maintenance operations meet and satisfy expectations. Consideration of the business goals and objectives determined during a series of meetings with state transportation agency professionals from all levels, including winter operations engineers, county commissioners, patrol supervisors, and program managers, led directly to identification of the performance measures. Consequently, the measures directly tie to the business processes and performance of operations. After baseline values of the measures are established, changes in performance can be related to cost of the technology.
Predicting Weather and Road Conditions: Integrated Decision-Support Tool for Winter Road-Maintenance Operations
Authors: Mahoney William P. , Myers William L.
Published: April 2007

Winter road-maintenance practitioners have expressed a strong interest in obtaining weather and road-condition forecasts and treatment recommendations specific to winter road-maintenance routes. These user needs led the FHWA Office of Transportation Operations Road Weather Management Program to support the development of a prototype winter road-maintenance decision-support system (MDSS). The MDSS is a unique data-fusion system designed to provide real-time treatment guidance (e.g., treatment times, types, rates, and locations) specifically regarding winter road-maintenance routes to winter maintenance decision makers. The system integrates weather and road data, weather and road-condition model output, chemical concentration algorithms, and anti-icing and deicing rules of practice. FHWA began the multiyear project in 2001 by engaging several national laboratories that had expertise in weather prediction and winter road engineering. A user-needs assessment for surface transportation weather information, performed by FHWA in 2000, formed the basis for the development effort. FHWA required that the system be developed in an open environment with significant input from the stakeholders (state transportation personnel and private-sector meteorological services). The resulting technologies have been released (in an initial version) on a nonexclusive basis to the surface transportation community. It is anticipated that the prototype MDSS will provide a springboard for the development and rapid deployment of operational systems by the private sector.
More Effective Winter Maintenance Method for Cycleways
Authors: Bergström A.
Published: April 2007

Increased cycling as a means of personal travel could generate environmental benefits if associated with a corresponding decrease in car-based transport. For promoting cycling during winter, the maintenance service level of cycleways is of importance. Earlier studies indicated that the Swedish public is unsatisfied with the service levels provided on cycleways during winter. In Sweden, cycleways normally are cleared of snow through plowing and are gritted for skid control. Field studies tested an unconventional winter maintenance method that uses a power broom for snow clearance and salt for deicing. The field studies were evaluated through road-condition observations, measurements of friction, a questionnaire survey, interviews, and bicycle measurements. The method of using a power broom for snow clearance and salt for deicing provided a higher service level than traditional winter maintenance methods, but it was two to three times more expensive. The method has greater potential in regions, such as southern Sweden, with low snow accumulations but with major ice-formation problems than in regions with a colder climate. Cyclists noticed the improved maintenance service level provided with the method used in the field study, but although cyclists stated that road condition is important to their decision to cycle, it could not be concluded that the enhanced service level generated a higher winter cycling frequency.
Evaluation of Performance of Permanent Pavement Markings
Authors: Parker Neville A. , Meja Massawe S. J.
Published: April 2007

As an implementation strategy of the federal retroreflectivity standards requirement for pavement markings, the New Jersey Department of Transportation (DOT) evaluated its 3-year fixed-schedule restriping strategy, to determine if it is consistent with the actual service life of the pavement markings. The methodology and results of the study are presented. Two types of data were collected: measured retroreflectivity by using LaserLux and subjective ratings from a survey conducted with the participation of the New Jersey driving public along a 32-mi circuit. Multiple regression techniques were used to correlate the average scores reported by the study participants for each specific roadway section with the corresponding measured retroreflectivity. The results suggested that the threshold value of an acceptable versus unacceptable level of retroreflectivity appeared to be between 80 and 130 mcd/m2/lux for New Jersey drivers younger than 55 and between 120 and 165 mcd/m2/lux for drivers older than 55. These results are consistent with conclusions reached by other investigators in similar research, where results generally ranged between 70 and 170 mcd/m2/lux. Interim visibility indices were developed for each age group per pavement-marking type. New Jersey DOT used the indices to determine and prioritize needs and to quantify needed related resources, on the basis of the threshold between acceptable retroreflectivity and unacceptable retroreflectivity, when it developed its pavement-marking management system. This approach also allows for cost-benefit and life-cycle analysis for different pavementmarking materials.
Developing Updated Minimum In-Service Retroreflectivity Levels for Traffic Signs
Authors: Carlson Paul J. , Hawkins H. Gene , Schertz Greg F. , Mace Douglas J. , Opiela Kenneth S.
Published: April 2007

Background and current status of the development of updated minimum in-service retroreflectivity levels for traffic signs in the United States are described. A summary of the earlier work, conducted from the late 1980s to the mid-1990s, is provided along with descriptions of the relevant validation work. Related events that occurred in the late 1990s are described, and it is shown how, when combined with the assumptions and limitations of the earlier minimum retroreflectivity research, they resulted in a need for updated minimum retroreflectivity levels. The research related to the updated minimum retroreflectivity levels is summarized. A brief description of a second round of national minimum retroreflectivity workshops is also provided. The most recent set of recommended minimum retroreflectivity levels for traffic signs is presented along with a list of suggested research topics based on the limitations associated with the recommendations.
Effect of Very High-Speed Traffic on the Deterioration of Track Geometry
Authors: López-Pita Andrés , Robusté Francesc
Published: April 2007

The new high-speed rail line between Madrid and Barcelona has been designed so that commercial vehicles can operate at maximum speeds of up to 350 km/h (219 mph). Criteria are outlined that have been adopted by the Spanish railways to ensure that the track geometry deterioration on the new Madrid–Barcelona line will be no greater than the track geometry deterioration found on the existing high-speed line between Madrid and Seville [300 km/h (187 mph)]. Attention has focused on two primary factors—( a) reduction of axle load and unsprung mass of the vehicles and ( b) reduction of the vertical rigidity of base plates between sleepers and rails.
Design Calculations for Embedded Rail in Asphalt
Authors: Huurman M. , Markine V. L. , de Man A. P.
Published: April 2007

In built-up areas, embedded rail structures have more advantages than conventional paved-in tramways. In the Netherlands, embedded rail structures are constructed solely of cement-bound concrete. These structures perform perfectly under both road and rail traffic and have significantly reduced noise and vibration in the tramway environment. Cement-bound concrete is, however, not applicable in all circumstances. To expand the applicability of embedded rail, the possibilities of embedded rail in asphalt (ERIA) were investigated. Cement-filled, porous asphalt was considered as the bitumen-bound alternative for cement-bound concrete. To determine if ERIA is feasible, the study first examined the stresses and strains that develop in cement-filled porous asphalt and in the bedding mass. The stresses and strains were determined for representative road and rail traffic loading by numerous finite element models. For both the asphalt and bedding mass, material design requirements were calculated. The mechanical properties of the materials were then studied to determine whether or not the materials comply with the design requirements and are suitable for application in this new type of embedded rail structure.
Influence of Track Maintenance on Lateral Resistance of Concrete-Tie Track
Authors: Sussmann Theodore , Kish Andrew , Trosino Michael
Published: April 2007

Adequate lateral resistance is required to provide the stable track structure necessary for safe rail operations on passenger and freight railroad track. Insufficient lateral resistance, coupled with a large thermal compression force in the rail from high rail temperature, can buckle the track structure. Railroads typically use mechanical stabilization, slow orders, or both, following maintenance operations that disturb the ballast section, such as track surfacing and alignment. Tests were conducted to improve the understanding of lateral resistance variations on concretetie track caused by surfacing and subsequent stabilization or compaction. Factors influencing track stability are summarized, maintenance procedures are described, the single-tie push test is described, and test results are presented. Tests were conducted to evaluate the changes in lateral resistance, from the trafficked, well-consolidated track structure before surfacing and alignment through the laterally weak track structure after surfacing. The influence of stabilization on the lateral resistance of the track structure was evaluated. The tests results indicate that surfacing significantly reduces the lateral stability of the track to a potentially critical level. Mechanical stabilization following surfacing significantly increased the lateral stability of all sections tested.
California Statewide Intelligent Transportation Systems Plan Evaluation: Case Study of Conformity with National Intelligent Transportation Systems Architecture
Authors: Golob Jacqueline M. , Stecher Cheryl C. , Felkins Cathy
Published: April 2007

A statewide evaluation was conducted of Intelligent Transportation Systems (ITS) Strategic Deployment Plans in California. It found that all 12 plans covering the state will conform by April 8, 2005, with Federal Highway Administration and Federal Transit Administration ITS Architecture and Standards: Final Rule. Developing the plans greatly raised the knowledge and awareness of the potential benefits of integrated technology systems. Multiple layers of architecture have been identified, particularly in Southern California, where developments are most advanced. Experience with deployment of an interregional system of data exchange, Showcase, indicates that such systems require far more time and resources than could have been anticipated at the outset. Technology obsolescence and software documentation have become key issues that other regions will face as projects move from plans to major deployments. Funding the operation and maintenance of these systems is emerging as a major barrier to their successful implementation. So too is the need to educate senior management and elected officials about the infrastructure requirements of successful system integration. Funding the operations and maintenance and configuration management of systems will undoubtedly be the issue for focus in the next decade, as transportation professionals begin to fully understand the implications of the concept of regionally integrated ITS.
Potential of Advanced Traveler Information System to Reduce Travel Disutility: Assessment in Washington, D.C., Region
Authors: Shah Vaishali P. , Wunderlich Karl , Toppen Alan , Larkin James
Published: April 2007

A study quantified the potential benefit of a pretrip advanced traveler information system (ATIS) to travelers in the Washington, D.C., region for the commuter objective of consistently on-time arrival. Paired driver commutes were simulated with a 15-month archive of regional travel times from Smar Traveler.com, an Internet provider of real-time data on travel time. One driver used a personalized pretrip notification service in selecting departure time and route, while the paired counterpart maintained a habitual trip departure time and route. The pairs’ trip arrivals were compared to quantify the effects on time management of a prospective notification service prescribing departure time and route. Approximately 25.9 million paired driver trials were modeled across a network of 55 nodes and 150 links, traversing 711.8 mi of roads in the Washington, D.C., metropolitan region. Trips were simulated for arrivals at 15-min intervals between 6:30 a.m. and 6:30 p.m. on workdays from each node to every other node. Overall, regular use of the pretrip ATIS is shown to benefit commuters whose objective is arriving on time. At low levels of ATIS market penetration, routine ATIS use could reduce early arrivals by 56% and late arrivals by 52%. Benefit in vehicle travel time is minimal. By applying a utility function to each trip, it was calculated that ATIS service reduces aggregate travel disutility by 15%. Approximately 67% of trips (origin–destination) derive a net benefit from routine ATIS use, while 40% benefit by more than $60/year. Benefits are fairly distributed across the year and are generally greatest during the evening peak.
Cost-Effectiveness of Intelligent Transportation System (ITS) Deployment in a Medium-Sized Area: Case Study with ITS Deployment Analysis System
Authors: Sadek Adel W. , Baah Bernard
Published: April 2007

To help transportation planners, the Federal Highway Administration (FHWA) has recently sponsored the development of a sketch planning analysis tool for estimating the benefits and costs of intelligence transportation system (ITS) deployment. Called the ITS Deployment Analysis System (IDAS), the tool was developed by Cambridge Systematics for FHWA and operates as a postprocessor to traditional planning models that are based on the four-step planning process. IDAS was used to predict the likely benefits of deploying ITS in Chittenden County, Vermont, a medium-sized region in northwestern Vermont, to gain insight into IDAS’ applicability in evaluating ITS benefits. A sensitivity analysis was also conducted to assess the sensitivity of IDAS’ results to the choice of values of some of the model’s parameters. The sensitivity analysis demonstrates that some of the model’s parameters tend to have a more significant impact on the results than others. Finally, the results indicate that, for medium-sized areas similar to Chittenden County, coordination of signals along major arterials and transit projects for automatic vehicle location and scheduling appear to be more cost-effective than freeway and incident management systems.
Interpreting Cellular Coverage for Transportation Applications
Authors: Walton Scott , Meyer Eric
Published: April 2007

The process was developed for collecting and analyzing cellular coverage data by applying the results of analysis to analog cellular coverage in the state of Kansas. The type of analysis that is appropriate depends on the purpose for which the information is to be used. Two types of analyses were examined—fixed coverage and mobile coverage. Fixed coverage analysis is needed for such functions as automatic collision notification in which any individual cellular connection can occur from a fixed location. The study showed that the fixed cellular coverage of the Kansas state highway system was good. Only 0.4% of the highway by length had inadequate signal strength for using a 3-W phone (a typical car phone) and 1.7% for using a 0.6-W phone (a typical handheld unit). In contrast, the mobile coverage analysis identified numerous areas where a call from a moving vehicle would be severely limited in duration. This type of analysis is needed for applications such as communications for emergency medical services, for which a vehicle must sustain continuous communications. For example, more than 9% of the state highways by length cannot sustain a call of 30 min with a 0.6-W phone, and in some areas the percentage is considerably higher. For certain applications, this difference may simply translate to inconvenience, but for other purposes it can be very important. The results of the two types of analyses highlight different characteristics of the coverage footprint; one addresses absolute coverage and the other continuity of coverage. The results of the analysis technique relate more directly to the unique characteristics of wireless communications utilization in transportation applications.
Anonymous Vehicle Tracking for Real-Time Traffic Surveillance and Performance on Signalized Arterials
Authors: Oh Cheol , Ritchie Stephen G.
Published: April 2007

One of the fundamental requirements for facilitating implementation of any advanced transportation management and information system (ATMIS) is the development of a real-time traffic surveillance system able to produce reliable and accurate traffic performance measures. This study presents a new framework for anonymous vehicle tracking capable of tracing individual vehicles by the vehicle features. The core part of the proposed vehicle tracking method is a vehicle reidentification algorithm for signalized intersections based on inductive vehicle signatures. The new vehicle reidentification system consists of two major components: search space reduction and probabilistic pattern recognition. Not only real-time intersection performance but also intersection origin–destination information can be obtained as the algorithm’s basic output. A systematic simulation investigation was conducted of the performance and feasibility of anonymous vehicle tracking on signalized arterials using the Paramics simulation model. Extensive research experience with vehicle reidentification techniques on single roadway segments was the basis for investigating the performance that could be obtained from tracking individual vehicles across multiple detector stations. The findings of this study serve as a logical and necessary precursor to possible field implementation of vehicle reidentification techniques. The proposed anonymous vehicle tracking methodology with existing traffic surveillance infrastructure would be an invaluable tool for operating agencies in support of ATMIS strategies for congestion monitoring, adaptive traffic control, system evaluation, and provision of real-time traveler information.
Specialty Vehicle Platform Results for Intelligent Vehicle Initiative: Minnesota Field Operational Test
Authors: Estochen Brad
Published: April 2007

In November 1999, the U.S. Department of Transportation Federal Highway Administration (FHWA) awarded a major Intelligent Vehicle Initiative grant to the Minnesota Department of Transportation (Mn/DOT). Minnesota’s project was a 3-year Generation 0 Specialty Vehicle field operational test for technology that gives lateral guidance and collision avoidance warnings to drivers in low-visibility conditions. Along with Mn/DOT and FHWA, other public and private partners participated in the project. Active operational testing was conducted over the winter of 2001–2002. The purposes of the project were to identify the technology’s safety and operational impacts, to guide future decisions on the technology’s installation on specialized vehicles, and to encourage the development and appropriate deployment of such systems on all vehicle platforms. The technologies were tested in four snowplows, a Minnesota State Patrol squad car, and an ambulance on a 50-mi rural highway. A key aspect of the project was optimizing driver interfaces from the perspective of study of the human factors involved. An overview of the project, including technologies, evaluation, and findings, is presented.
System Integration and Field Tests for Developing In-Vehicle Dilemma Zone Warning System
Authors: Moon Young-Jun , Lee Jooil , Park Yukyung
Published: April 2007

The basis for system integration and field testing was developed for assessing a dilemma zone warning system for signalized intersections. The system consists of hardware (an in-vehicle warning device, roadside antenna, and traffic signal controller) and software to operate and test the integrated component warning and communications systems. Field tests were conducted in real traffic situations to test the system’s warning initiation time from the signal controller, the activation and duration of the visual and audible signals, and the warning delay, on the basis of relationships between distance variables that include the safe stopping distance and the location of roadside antenna. Findings from the field tests at two signalized intersections indicated that the system could be implemented at signalized intersections to eliminate the dilemma zone, relative to approach speeds, and to reduce red-light violations and intersection collisions by means of an in-vehicle warning device.
Robotic Machine for Highway Crack Sealing
Authors: Bennett D. A. , Feng X. , Velinsky S. A.
Published: April 2007

An operator-controlled crack-sealing machine was developed and tested at the Advanced Highway Maintenance and Construction Technology (AHMCT) Research Center at the University of California, Davis. The machine, integrated onto a single truck, provides ease of operation and a simple, automated method of sealing random pavement cracks. The operator provides the machine its tasks and is the decision maker; the machine automatically performs the repetitive and dangerous tasks of mapping pavement cracks, creating seal paths for the robot, and sealing the cracks. The operator communicates with the machine through a simple user interface adjacent to the driver. This operator control approach drastically reduces the machine’s control complexity relative to fully automated crack-sealing machines. To be able to seal cracks within a full lane without intruding into adjacent lanes, a telescoping long-reach robotic arm was developed that can position the sealing head mounted to its end in a large 3.7- x 4-m (12- x 13-ft) workspace, within 0.4 mm (1/64 in.) at a traverse speed up to 1 m/s (3 ft/s). A special sealant applicator that deploys a pressurized reservoir was developed to allow high-speed and automated sealing operations. A 100-Mbps fast Ethernet and 10-Mbps wireless control network allows for distributed real-time motion control, input/output control, and machine vision. A fully object-oriented, multithreaded Internet-based software architecture allows reliable and efficient system integration and provides an interactive and responsive user interface for feature-rich and easy imaging, path planning, and system control.
Prediction Method for Response of Steel Bridge Beams and Girders to Blast and Fragment Loads
Authors: Baylot James T. , Ray James C. , Hall Robert L.
Published: April 2007

The military requires methods of predicting the response of steel bridge beams and girders to blast and fragment loads. The methods must provide quick answers to analysts who have very little experience, if any, in the blast response of structures. Similar tools also would be beneficial to transportation engineers who must evaluate bridges against terrorist events. Because data on the response of these beams to blast and fragments are extremely limited, finite element simulations were performed to create a numerical database that includes the typical range of steel bridge and girder dimensions. The simulation results were used to determine the loading characteristics that significantly affect the response. Loading characteristics were reduced to a load measure, a single number that can be easily computed for any combination of fragment and blast loads. If the load measure is exceeded for a given combination of blast and fragment loads, then beam failure is predicted. A computer code was developed to predict fragment and blast loads from conventional weapons and to determine the load measure for any given load case so an analyst with knowledge of weapon and beam geometry can easily predict whether a beam will fail. Model development and validation are presented. The model was developed to predict the response of bridge beams and girders to conventional weapons but could be extended to a model for predicting the response to terrorist weapons.
Economic Value of Walkability
Authors: Litman Todd Alexander
Published: April 2007

There are ways to quantify the value of walking (the activity) and walkability (the quality of walking conditions, including safety, comfort, and convenience). Walking and walkability provide a variety of benefits, including accessibility, consumer cost savings, public cost savings (reduced external costs), more efficient land use, community livability, improved fitness and public health, economic development, and support for equity objectives. Yet current transportation planning practices tend to undervalue walking. More comprehensive analysis techniques are likely to increase public support for walking and other nonmotorized modes of travel.
Analysis of North Carolina Guidelines and Criteria for Establishing School Walk Zones
Authors: Tsai Jeff , Rhoulac Tori , Henry Andrew J. , Hall William L.
Published: April 2007

The North Carolina Department of Transportation’s Division of Bicycle and Pedestrian Transportation sponsored research to examine the potential for developing school walk zone guidelines for the state. State law establishes a zone within a 1.5-mi radius of a school in which school bus transportation is not provided, “unless road or other conditions shall make it inadvisable to do so.” Quantifiable guidelines are needed to clearly define the exception conditions to this law and to guide school officials in establishing and evaluating walking and biking corridors within this zone. To examine the opportunities, issues, and risks associated with school walk zones, the project team conducted a survey of North Carolina school transportation directors, focus groups with parents, students, and school and local government officials, and a spatial analysis of school-related pedestrian crashes. Results and conclusions led to several recommendations. They include clarifying and defining key terms, such as “walk zone” and “no-transport zone”; developing quantifiable guidelines to help school officials identify preferred walking corridors; and establishing local partnerships with representatives from public works, schools, departments of transportation, police, and community organizations. Also, pedestrian and bicycle safety and access issues should be included in the local school siting process, and pedestrian and bicycle training should be increased in elementary and middle schools. Other recommendations are to change the crash data collection process to better identify school commute crashes and to conduct further research on school walk zones and no-transport zones, to better understand their impact on modal split, school campus traffic congestion, school commute safety, and public costs.
Toward Vision Zero at Zebra Crossings: Case Study of Traffic Safety and Mobility for Children and the Elderly, Malmö, Sweden
Authors: Johansson Charlotta , Gårder Per , Leden Lars
Published: April 2007

The Swedish Vision Zero’s goal is to eliminate all fatalities and incapacitating traffic injuries. One step toward Vision Zero is through traffic calming. Code changes are also part of this effort. The Swedish Code concerning car drivers’ responsibility to give way to pedestrians was strengthened in 2000. A study was done to evaluate the short-term effects of the change in the code, as well as of the reconstruction of urban intersections to eliminate overtaking and speeding over 30 km/h. The focus of the evaluation was on children and elderly people, as pedestrians and cyclists. Between 1995 and 1999, an average of 7 pedestrians were killed and about 60 seriously injured at unsignalized zebra crossings. In 2001, those numbers were 8 and 70, respectively, despite the fact that some crosswalks were eliminated in connection with the change of the code. The conclusion is that the change of code has not improved safety. Field studies in Malmö in regard to behavior, speed, and conflicts, as well as analysis of crash data, show that the code change has increased mobility for cyclists, whereas motor vehicle speeds did not change significantly. The reconstruction increased mobility further and, at least based on indirect measures, improved safety. Also, safe traffic behavior, expressed as one’s looking sideways, increased somewhat at the reconstructed intersections, but stopping at the curb before crossing the street decreased. Children and the elderly did not benefit more than people in other age groups.
Measuring Pedestrian Quality of Service for Midblock Street Crossings: Selection of Potential Determinants
Authors: Chu Xuehao , Baltes Michael R.
Published: April 2007

The Florida Department of Transportation is in the process of developing a statistically estimated model of pedestrian quality of service for midblock street crossings as part of its Multimodal Quality of Service Program. This model is to be used in evaluating the level of service of street segments for pedestrian street crossing. The actual development of the model, including methodological issues explored, data collection, and model calibration and validation, is reported separately. A process was used to select potential determinants of perceived pedestrian quality of service for midblock street crossings. This process is structured and involves two steps. The first step involves the selection of a set of potential determinants through a theoretical analysis of pedestrian behavior for street crossing. The theoretical consideration ensures that these potential determinants have a sound behavioral foundation. The second step involves narrowing down this theoretical set through a practical analysis of planning needs and data requirements by an advisory committee. This practical consideration ensures that the final set of potential determinants and the model both are practically relevant.