bluuebunny/crossref_metadata_2025 huggingface dataset:
ARTIMIS Telephone Travel Information Service: Current Use Patterns and User Satisfaction
Authors: Aultman-Hall Lisa , Bowling Sarah , Asher Jill Clemons
Published: April 2007

In February and March 1999, an ARTIMIS (advanced regional traffic interactive management and information system) traffic advisory telephone service (TATS) user satisfaction survey was conducted. Evaluation of the Greater Cincinnati and northern Kentucky service had the following objectives: (a) to assess overall satisfaction; (b) to determine the preference of access with an N11 dialing code; and (c) to determine the influence on travel behavior. A total of 65 percent of users indicated they would be willing to pay for the service. On average, the maximum amount people would pay per call is $0.25. Users were asked what portion of the time the traffic information affected their travel behavior: route taken (average, 71 percent of the time), departure time (average, 34 percent), and destination (average, 25 percent). The information rarely affected mode used; however, users indicated that, on average, they postponed their trips 14 percent of the time. About 80 percent of the users believed they would personally benefit from a nationwide N11 dialing code. The study results suggest that a nationwide three-digit access code for traffic information would be a benefit to overall system performance. According to the analysis, the respondents indicated they make an average of 19 trips per year to other areas where they could use a service like ARTIMIS TATS. Users change their travel behavior as a result of the traffic information. They were very satisfied with the service. There was a preference, and good recall, for the 211 number currently provided by the Kentucky Transportation Cabinet and the Ohio Department of Transportation in northern Kentucky and Cincinnati, which replaced a seven-digit number.
Seattle Metropolitan Model Deployment Initiative Evaluation: Results and Key Findings from Modeling
Authors: Wunderlich Karl , Bunch James , Larkin James
Published: April 2007

At the request of the Joint Program Office for intelligent transportation systems (ITS) of the FHWA, Mitretek Systems conducted a modeling analysis of ITS impacts in support of the metropolitan model deployment initiative evaluation program. The Mitretek modeling study supports the evaluation of the Seattle model deployment Smart Trek, testing a series of hypotheses that could not be addressed in controlled field studies or survey research. Using both a regional planning model and a subarea simulation, the study includes a series of experiments to quantify impacts from integrating ITS technologies and services both across jurisdictions and between functional components. The analysis addressed ( a) subarea-wide impacts of traffic signal coordination on major arterials, ( b) the impact of integrating arterial data into the current freeway-based advanced traveler information service (ATIS), and ( c) interactions at the corridor and the regional levels from concurrent deployment of signal coordination and the enhanced freeway and arterial ATIS. Results from that study have been summarized, detailing findings for a 300-km2 mixed freeway and arterial subarea network drawn from the roadway system north of downtown Seattle. The coordination of traffic signals along two major arterials resulted in a 7 percent reduction in overall subarea delay and a 3 percent reduction in total stops. More efficient route diversions for ATIS users result from the integration of arterial data into the current web-based service. At currently estimated levels of ATIS usage (6 percent of travelers), this improved diversion efficiency reduces overall subarea delay (users and nonusers) by over 3 percent.
Franchising and Refranchising of Passenger Rail Services in Britain
Authors: Preston John
Published: April 2007

The franchising of passenger rail services in Great Britain that occurred in 1996–1997 and the refranchising of these services are under review. The initial impact of franchising has been broadly beneficial and demand is rising, whereas the costs to government are declining. However, important issues relating to service performance, customer satisfaction, and investment in rolling stock have emerged. Refranchising is designed to address these problems and is under way. The franchising and the refranchising processes appear to have been successful in stimulating competition for the passenger rail market, but contract design issues concerning franchise length, size, and structure have not yet been satisfactorily resolved. Furthermore, there are important issues regarding the extent to which service quality is contractible and verifiable. There are also dangers of adverse ratchet effects and regulatory capture occurring. Some lessons for other countries are highlighted.
Injury Severity in Multivehicle Rear-End Crashes
Authors: Khattak Asad J.
Published: April 2007

Rear-end crashes constitute a substantial portion of the total crashes in the United States. They are also amenable to reduction through emerging intelligent transportation systems technologies such as crash warning systems. A specific objective was to analyze the effect of information and vehicle technology on injury severity in rear-end crashes, while controlling for the effects of driver, vehicle, and roadway factors. The study is based on real-life data from the Highway Safety Information System for North Carolina access-controlled roadways. The results show that in two-vehicle crashes the leading driver is more severely injured, whereas in three-vehicle crashes the driver in the middle is more severely injured. To analyze injury severity on the KABCO scale, three separate ordered probit models were estimated for Drivers 1 (leading), 2 (striking), and 3 (striking, in a three-vehicle crash). A vehicle age variable was used in the model specification to capture the effect of vehicle age and to serve as a proxy for safety improvements, in particular the center high-mounted stoplight (CHMSL). The modeling results show that being in a newer vehicle protects the driver in rear-end collisions. Similarly, being in a newer vehicle protects Driver 2. Interestingly, striking a newer Vehicle 1 can reduce the chance of both Driver 2 and Driver 3 injuries, partly as a result of CHMSL on Vehicle 1. Also examined is whether drivers of vans, pickup trucks, and station wagon cars/trucks sustain less-severe injuries because of their larger vehicle mass or more-severe injuries because of their information-blocking effect. The results show that technological improvements have a quantifiable beneficial effect on safety.
Reliability and Accuracy of Routine Inspection of Highway Bridges
Authors: Phares B. M. , Graybeal B. A. , Rolander D. D. , Moore M. E. , Washer G. A.
Published: April 2007

Routine inspection is the most common type of highway bridge inspection completed to satisfy the requirements of the National Bridge Inspection Standards. Routine inspections of highway bridges are typically completed using only visual inspection (VI) and rely heavily on subjective assessments made by bridge inspectors. Given this practice and the fact that VI may have limitations that affect its reliability, the Federal Highway Administration completed a comprehensive study to examine the reliability of VI as it is currently practiced in the United States. The accuracy and reliability of condition ratings generated through routine inspections of six in-service and decommissioned highway bridges were studied. These timed inspections were completed in normal summer weather conditions under direct observation. To ensure that results from this study would be applicable to normal bridge inspections, state department of transportation bridge inspectors made up the study sample, which included 49 inspectors from 25 states, representing a diverse cross section of the bridge inspector population. Results of the study indicate that routine inspections are completed with significant variability. Specifically, 95 percent of primary bridge element condition ratings will vary within two rating points of the average, and only 68 percent of these ratings will vary within one rating point. Additionally, the National Bridge Inspection Standards definitions of condition rating may not be sufficiently refined to allow for reliable routine inspection results.
Field Test of New Procedure for Removing Lead-Based Paint from Bridges
Authors: Bushman William H. , Jackson Donald R.
Published: April 2007

Removing the failed and failing lead-containing paint on the more than 7,000 steel-beam highway bridges maintained by the Virginia Department of Transportation is an increasingly vexing problem given issues regarding the environment, worker health, and cost. The expense and liability associated with the paint debris generated as well as the debris resulting from the removal procedure further complicate the issue. The situation nationally is more dramatic: of approximately 200,000 structures, 80 to 90 percent have lead-based paint. Proven in the laboratory, the Electrostrip procedure, which uses an electrochemical treatment to cause paint to debond from steel, was tested in the field. The technology was first used at a production level to remove 74 m2 of lead-based paint from a bridge in service on the Virginia Interstate system. Over 7 workdays, this method was used to remove the lead-based existing and original paint system and generated 63 percent less solid debris than full abrasives blasting would have done. Although the production rate was lower than with more conventional techniques, greater environmental and worker protection was achieved with Electrostrip than with any other paint removal method demonstrated and documented thus far.
Microscopic Model of Air Pollutant Concentrations: Comparison of Simulated Results with Measured and Macroscopic Estimates
Authors: Young Park Jin , Noland Robert B. , Polak John W.
Published: April 2007

Road traffic is a major source of air pollution, and substantial effort is currently being devoted to the development of both technological and transport policy measures to reduce the impacts. It is well established that the emission of certain pollutants is closely related to both traffic speed and fluctuations in traffic speed. However, conventional transport emission models are largely based on average traffic conditions, and thus they cannot properly represent the effects of policy measures, such as automatic speed control or traffic calming, that directly affect the speed dynamics of the traffic stream. Given the prevalence of such policies, there has been considerable effort to develop improved emissions modeling capabilities. A new approach to the microscopic modeling of air pollution from road traffic is described. This approach can represent detailed speed fluctuations in the flow of traffic, and it is applied to a local network in Maidstone, Kent, in the United Kingdom. A stochastic microscopic traffic flow simulation model (VISSIM), an existing speed-based emission database (MODEM), and a Gaussian dispersion model are combined. Simulated results are compared with a macroscopic model of air pollutant concentrations (DMRB method) and roadside pollutant measurements. Results are encouraging and show a good comparison with the DMRB method and, with some exceptions, good comparisons with trends in measured pollutant concentrations. Statistical differences in the methods, however, suggest that either measurement error or other inaccuracies are present.
Shared, Small, Battery-Powered Electric Cars as a Component of Transportation System Sustainability
Authors: Bernard Martin J. , Collins Nancy E.
Published: April 2007

Six U.S. trends are explored that may change how transportation systems and resources are used: changing demographics; questions about the future of highway infrastructure and maintenance; greater interest in alternative means of transportation; growth of telecommunications technologies; movement toward “access to services” rather than “ownership of goods”; and renewed interest in urban living. It is believed that shared, small, battery-powered electric cars can provide high-quality, cost-effective mobility to replace trips made in conventional cars, offer a viable alternative for changing lifestyles resulting from these trends, and move our global transportation systems toward sustainability. Although this paper is primarily intended to stimulate discussion and suggest future avenues for research, descriptions and examples of shared-car systems using small electric cars that complement the six trends are included. Although the current effort has focused on North America, thinking is beginning to expand internationally because a sustainable transportation system is a global necessity. Any two of the six trends could well cause an evolution in the U.S. transportation system, but all six combined certainly will. Similar trends can be found in other developed countries. Developing countries face even more severe transportation problems due to lack of resources to solve these problems as they arise.
Guidelines for Opposing Left-Turn Lane-Line Widths
Authors: McCoy Patrick T. , Pesti Geza , Byrd Patrick S. , Singh Virendra A.
Published: April 2007

Vehicles turning left at intersections from opposing left-turn lanes often restrict each other’s sight distance. Previous research has developed guidelines for offsetting opposing left-turn lanes to provide adequate sight distances. Implementation of these guidelines at existing intersections typically involves reconstructing the left-turn lanes. However, increasing the width of the lane lines between left-turn lanes and the adjacent through lanes has also been found to improve the sight distance between opposing left-turn lanes. Using the relationship found between lane-line width and available sight distance, guidelines for designing the width of left-turn lane lines to provide the required sight distance for opposing left-turning vehicles are presented.
Inductive Learning Approach to Evolutionary Decision Processes in Activity-Scheduling Behavior: Theory and Numerical Experiments
Authors: Arentze Theo , Timmermans Harry
Published: April 2007

The development of an inductive learning agent for simulating evolutionary processes (Ilse), which is meant to be linked to the ALBATROSS model, is discussed. The agent was developed to simulate learning and adaptation in travel behavior. It is assumed that at the start of the process, characterized by a high degree of uncertainty, individuals will display information-seeking behavior and choose the alternative that maximizes the entropy of outcomes. As learning proceeds, individuals will switch to goal-seeking behavior and select the alternative that maximizes the expected size of the outcome value. A series of computer experiments using simulated data were conducted to illustrate the system. Simulations showed that the system is able to learn even under conditions of noisy feedback, irrelevant attribute information, and fairly complicated interactions between relevant attributes. A combined information- and goal-seeking strategy increases learning speed.
Travel Behavior Implications of Information and Communications Technology in Puget Sound Region
Authors: Viswanathan Krishnan , Goulias Konstadinos G.
Published: April 2007

The explosive growth of information and communications technology (ICT) has given rise to new paradigms in the manner in which business is conducted and in which people conduct their everyday affairs. This new dimension has the potential to affect travel behavior in direct and indirect ways and has possible policy implications for transportation planning. A multivariate multilevel analysis is presented using data from the Puget Sound region. ICT use effects on travel behavior are examined in terms of activity and travel time expenditures in a day. Model formulation in the study accounts for day-to-day variation, controls the close relationship between activity participation and travel, and incorporates the contextual influence of households on individual behavior by using observed and unobserved heterogeneity regression model components. The findings in this study indicate that Internet use at home and in the workplace is associated with a reduction in travel times. In contrast, mobile technology use is associated with significantly longer travel times. However, the high level of person-to-person variance of this effect shows that there may be groups of people using technology in radically different and most likely conflicting ways (e.g., one group uses mobile technology to consolidate trips and the other to reach activity opportunities that require longer travel times). In terms of activity participation, none of the technologies appears to be a significant contributor to the difference in behavior among technology users and nonusers.
Sign Retroreflectivity: Comparing Results of Nighttime Visual Inspections with Application of Minimum Retroreflectivity Values
Authors: Hawkins H. Gene , Carlson Paul J.
Published: April 2007

In 1993, FHWA published research recommendations for minimum levels of retroreflectivity for traffic signs. These values were later revised in a 1998 FHWA report. The minimum values were developed as part of a process to add end-of-service life retroreflectivity values to the Manual on Uniform Traffic Control Devices. There have been few or no comparisons between the use of minimum retroreflectivity values to define end-of-service life and the results of typical nighttime visual inspections. Researchers at the Texas Transportation Institute conducted such an evaluation as part of a Texas Department of Transportation (TxDOT) sign workshop. In the evaluation, TxDOT sign crews evaluated 49 signs on an 8-km (5-mi) closed course. Each sign was rated as “acceptable,” “marginal,” or “unacceptable.” Vehicle headlamp illuminance was also measured. The results of the evaluations were compared with the application of the FHWA minimum values. The results show that whereas one sign did not meet the low-speed FHWA minimum values, the average ratings for the TxDOT sign crews indicated that 26 signs were not acceptable. The researchers identified several factors that affected the average sign ratings. These factors included the uniformity of the sign face, the type of sheeting material, and the retroreflectivity. The findings indicate that among the TxDOT sign crews participating in the evaluation, visual nighttime inspections result in a higher failing rate than does the application of the FHWA research recommendations for minimum levels of retroreflectivity. This finding indicates that visual sign inspections should be an important component of assessing the nighttime visibility of traffic signs.
Long-Term Effectiveness of Speed Monitoring Displays in Work Zones on Rural Interstate Highways
Authors: Pesti Geza , McCoy Patrick T.
Published: April 2007

The long-term effectiveness of speed monitoring displays (SMDs) was evaluated as part of the Midwest States Smart Work Zone Deployment Initiative, a pooled-fund study sponsored by Iowa, Kansas, Missouri, Nebraska, and FHWA. Three SMDs were deployed for a 5-week period along a 4.35-km (2.7-mile) section between two work zones on I-80 near Lincoln, Nebraska. The mean, 85th percentile, and standard deviation of vehicle speeds and the percentage of vehicles complying with the 89-km/h (55-mph) speed limit and the 97 and 105-km/h (60 and 65-mph) speed thresholds were used as measures of effectiveness (MOEs). The SMDs were found to be effective in lowering speeds, increasing the uniformity of speeds, and increasing speed-limit compliance over the 5-week period. Statistically significant improvements in speed parameters and speed-limit compliance were observed at the measurement points downstream of the first two SMDs. The improvement in standard deviation and some compliance percentages were not statistically significant at the third SMD. Greater speed reductions and compliance increases were observed for passenger cars than for other vehicles. The combined longterm effect of the three SMDs was also assessed using spatially aggregated MOEs. Statistically significant improvement was found in terms of both speed reduction and speed-limit compliance. One week after the removal of the SMDs, there were still statistically significant speed reductions and compliance increases, although they were less than during the deployment.
Legibility Distances of Fluorescent Traffic Signs and Their Normal Color Counterparts
Authors: Schnell Thomas , Bentley Keith , Hayes Elizabeth , Rick Martin
Published: April 2007

It is well known that fluorescent traffic signs have a daytime conspicuity that is far superior to that of normal color signs. This study was conducted to test the hypothesis whether adding the property of fluorescence, while leaving all (or in practical terms most) other sign features the same, does increase the legibility distance. Six diamond-shaped signs were fabricated and laminated with the normal colors on one side and their fluorescent color counterparts on the other. The investigated sign background colors included yellow, fluorescent yellow, fluorescent yellow green, pink, fluorescent pink, purple, and fluorescent purple. Four of the six signs used Landolt rings to avoid word familiarity issues. A pedestrian-crossing symbol sign and a “Plant Entrance” warning sign were used in addition to the Landolt ring signs. It was found that fluorescence actually did statistically significantly increase the legibility distances. However, the actual increases were fairly small from a practical point of view, ranging from 5.3 to 15.9 percent when adding the property of fluorescence. In general, for negative and positive contrast signs where both the legend and the background are fluorescent, a slight increase in the legibility distance can be expected. Note that the illumination conditions used (on a fair day) represent worst-case scenarios for fluorescent colors. Larger percent increases in legibility distance may be expected when using fluorescent colors during the time of twilight, overcast days, and daytime in inclement weather.
Implementation of Miniature Cone Penetrometer in Roadway Design and Construction
Authors: Titi Hani H. , Morvant Mark
Published: April 2007

A continuous-intrusion miniature cone penetration test (CIMCPT) system was developed, calibrated, and implemented by the Louisiana Transportation Research Center. The cone-penetration technology is fast, reliable, and cost-effective, especially when compared with the traditional site-characterization methods such as borings and laboratory and field tests. The implementation phase of the CIMCPT system in roadway design and construction in Louisiana is presented. The CIMCPT was used to evaluate the structural capacity of pavement shoulders to support diverted traffic during the I-10 rehabilitation near Rayne, to redesign and construct a stone base-course layer for State Route LA-182 in Franklin, and to evaluate the failure surface of the I-20/Missouri Pacific Railroad overpass embankment near Tallulah. The CIMCPT system was successfully implemented by the Louisiana Department of Transportation and Development (LA DOTD). Implementation of the CIMCPT technology in roadway design and construction has saved LADOTD money and time compared with traditional subsurface exploration techniques.
Automated Measurement of Total Suction Characteristics in High-Suction Range: Application to Assessment of Swelling Potential
Authors: Likos William J. , Lu Ning
Published: April 2007

An automated experimental system to characterize moisture-content-totalsuction relationships for unsaturated clayey soils is described. Unlike traditional techniques requiring independent measurement of total suction and moisture content (e.g., thermocouple psychrometry and filter paper), suction is directly controlled and corresponding moisture contents are continuously monitored. The system is applicable for total-suction values ranging between approximately 620 000 and 14 000 kPa. Total suction is controlled during testing by computer-automated rationing of “dry” and “wet” nitrogen gas in a closed environmental chamber. To develop characteristic curves, the equilibrium moisture content of soils placed in the chamber is measured with an integrated electronic balance as water vapor is absorbed or desorbed. The system requires no user intervention and is capable of generating characteristic curves, including wetting and drying loops, in a time span on the order of one to two weeks. Concurrent measurements using the noncontact filter paper method (ASTM D5298) are shown to agree very closely with those obtained from the automated system. Total-suction characteristic curves are compared for a highly expansive smectite clay and nonexpansive kaolinite clay. Hysteresis between the wetting and drying cycles and stepwise dehydration phenomena, which have been noted by previous researchers, are reproduced in the results. Comparison of the smectite and kaolinite characteristic curves demonstrates the system’s potential to become a simple, non-labor-intensive, quick, and reliable platform to qualitatively assess the relative swelling potential of clayey soils.
Safety Benefits of Intersection Approach Realignment on Rural Two-Lane Highways
Authors: Yuan Fei , Ivan John N. , Qin Xiao , Garrick Norman W. , Davis Christian F.
Published: April 2007

One task of traffic safety engineers is the identification of high crash locations and selection of appropriate highway treatments to reduce the number of crashes. This process relies on the availability of accurate information on crash reduction factors of various treatments. Currently, most agencies rely on information dating back to the 1960s. It is necessary to update and reassess these factors using new data and new evaluation methods. A before-and-after study is currently being conducted using empirical Bayesian methods to estimate crash reduction factors for modern conditions on two-lane rural highways. The results of the second phase of the study are reported, which aimed to evaluate the safety benefits of intersection approach realignment. Furthermore, an analysis of variance model is used to identify extra benefits of comprehensive treatments. The improvements studied appeared to reduce the total number of crashes, but the effect on type of crashes was different. Also, combining realignment with adding a left-turn lane or traffic signal does not appear to offer significant additional benefits in crash reduction.
Definition of the Light Vehicle Off-Roadway Crash Problem for the Intelligent Vehicle Initiative
Authors: Najm Wassim G. , Schimek Paul M. , Smith David L.
Published: April 2007

Off-roadway crashes involving light vehicles (passenger cars, sport utility vehicles, vans, and pickup trucks) were analyzed based on the 1998 General Estimates System crash database to support the development of countermeasure systems as part of the U.S. Department of Transportation’s Intelligent Vehicle Initiative. An off-roadway crash occurs when a vehicle in transport departs the road due to loss of control or crossing the edge of the roadway. Approximately 924,000 such crashes occurred in the United States in 1998. These crashes are grouped into six distinct precrash scenarios (3 × 2 matrix) based on vehicle movements (going straight, negotiating a curve, or initiating a maneuver) and critical events (departed roadway edge or lost control). These scenarios are described statistically in terms of their physical setting, which consists of the roadway type, land use, relation to junction, number of travel lanes, and speed limit. Moreover, factors that might have contributed to the cause of these crashes are identified. According to this analysis, 85 percent of these off-roadway crashes occurred on nonfreeways, 64 percent in rural areas, 83 percent away from junctions, 60 percent on two lanes of travel, and 62 percent below the 89-km/h (55-mph) speed limit. In addition, speeding and alcohol were reported in 25 and 20 percent of these crashes, respectively. Finally, inclement environmental conditions or driver inattention or distraction might have contributed to about 42 percent of these crashes.
Rear-End Collision–Warning System: Design and Evaluation via Simulation
Authors: Krishnan Hariharan , Gibb Scott , Steinfeld Aaron , Shladover Steven
Published: April 2007

The design of an innovative rear-end collision-warning system was evaluated for effectiveness. The crash scenario involves a lead vehicle not moving (LVNM) in one lane of a straight, dry, paved arterial road and a following vehicle approaching in the same lane. The LVNM has a rearfacing sensor and is equipped with the rear crash-warning system, which allows the LVNM to flash its brake lights or its center high-mounted stop lamp, warning the following vehicle that it is approaching too rapidly. Because this problem is complex, the scope was narrowed, and it was assumed that the driver of the following vehicle always detected the warning after a response time lag and then applied hard braking. The warning algorithm (i.e., selecting the most appropriate warning distance for each approaching vehicle speed) was designed based on trade-offs to maximize the capability of preventing crashes, reduce the frequency of nuisance alarms, and minimize the severity of crashes. The overall measures of effectiveness of the warning design were then evaluated for a vehicle speed distribution that represented a suburban arterial road. The findings suggest that the warning system should be very effective in preventing crashes. The expected number of nuisance alarms was small, and for the very small percentage of vehicles that would crash, the expected crash severity was negligible. Experimental studies and field operational tests would be required to obtain more accurate numerical values for the design parameters.
Effect of Automatic Vehicle Location on Schedule Adherence for Mass Transit Administration Bus System
Authors: Lee Young-Jae , Chon Kyung Soo , Hill David L. , Desai Nimish
Published: April 2007

The effect of an automatic vehicle location (AVL) system on schedule adherence and operator behavior is studied. During two sets of 4 weeks each, one set with and one set without AVL intervention, data were collected from the Mass Transit Administration (MTA) bus system in Baltimore, Maryland. Although AVL systems have many benefits, the focus is on improvements in schedule adherence and operator behavior for off-schedule bus arrival. Although ahead-of-schedule operation generates longer waiting time, adjustments can be made if the operator is aware and willing to keep on schedule. Thus, arrival status at the next time points (TPs), after early arrival at the main TPs, and link travel time between those two TPs were carefully analyzed. As a result, an improvement in schedule adherence with AVL was demonstrated with a 99 percent confidence level. However, with MTA’s current AVL intervention, the schedule adherence and link travel time after early arrival at the previous TP did not improve significantly. Those results are explained by the link travel time distribution curves, which have two peaks by two groups of operator behavior—one enjoying congestionfree traffic and the other paying attention to schedule adherence. Without strong AVL intervention, operator behavior could not be relied on to improve schedule adherence effectively.
Simulation Model for Evaluating Intelligent Paratransit Systems
Authors: Fu Liping
Published: April 2007

The latest advances in information technology, such as automatic vehicle location, digital telecommunications, and computers, have renewed interest among public transit agencies in applying these technologies to enhance the efficiency and reliability of their paratransit systems. This interest has also induced a need for relevant methodologies and tools that can help address some fundamental questions on the cost-effectiveness of these technologies. This type of evaluation has mostly relied on field studies that usually require a significant expenditure and are conditioned to limited operating environments. A simulation system is presented that has been developed to model a variety of technology-oriented dial-a-ride paratransit systems, offering a way to complement or replace the field evaluation method. The general concepts and models applied in the simulation system are discussed, focusing on how various components are modeled and how they interact with each other in the overall simulation framework. The simulation system is applied to evaluate the effects of trip cancellation on the operational performance of a partly synthetic paratransit system, with the goal of quantifying the potential benefits that may be attained by accepting real-time demand trips.
Washington State Department of Transportation Superpave Implementation
Authors: Leahy Rita B. , Briggs Robert N.
Published: April 2007

Washington State’s Department of Transportation (WSDOT) has investigated components of the Strategic Highway Research Program (SHRP)/Superpave technology to include performance-grade (PG) binder usage and specification validation, gyratory mix design, the Superpave Shear Tester, and field performance of Superpave mixes. With a focus on field performance, validation of the binder specification in respect to low-temperature cracking was accomplished using binder and field performance data from 28 projects. The results were encouraging: the original SHRP algorithm for binder selection correctly “predicted” field performance in 22 cases. The original SHRP algorithm was subsequently refined as part of FHWA’s Long-Term Pavement Performance (LTPP) Program. The LTPP algorithm used for binder selection correctly predicted field performance in 26 cases. Since 1993, of the 44 WSDOT projects with a Superpave technology component, 17 parallel Hveem and Superpave mix designs have been conducted. In 13, Superpave design asphalt content was equal to or greater than the Hveem design asphalt content, although the difference was insignificant. A conventional Hveem mix design was conducted on 18 projects using a PG binder (Hveem-PG). The remaining 26 projects were considered to be Superpave because materials selection and mix design were established in accordance with the Asphalt Institute’s SP-2, Superpave Level 1 mix design. According to WSDOT practice, the following indices trigger maintenance: pavement structural condition (PSC), rutting, or International Roughness Index (IRI). Although “young,” all 44 projects are performing well. The average values of rutting, PSC, and IRI are all below the “trigger” values. In rutting and PSC, performance of Hveem-PG and Superpave projects is virtually identical. However, ride quality of Superpave projects is rougher than that of Hveem-PG binder projects.
Nighttime Construction Issues
Authors: Hancher Donn E. , Taylor Timothy
Published: April 2007

The findings of the Kentucky Transportation Cabinet study, Nighttime Construction Issues, are summarized. The current state of nighttime construction was examined through a survey of nighttime construction practitioners. To determine the feasibility of performing a project at night, the factors that affect night operations are discussed as well as a nighttime project evaluation form. Because lighting is a crucial element of any night project, a new form of lighting technology is briefly discussed. An idea that is slowly gaining favor with transportation departments is outlined—the contractor-supplied work plan. Finally, ideas for improvements in public relations and recommendations for overall nighttime project improvement are discussed.
Critical Path Method–Line of Balance Model for Efficient Scheduling of Repetitive Construction Projects
Authors: Hegazy Tarek
Published: April 2007

A general model is presented for efficient scheduling and resource management in construction projects that involve a high degree of repetition, such as highways and pipelines. The proposed model has three main features: ( a) it fully integrates the critical path method for network analysis and the line of balance technique for linear scheduling, ( b) it allows realistic schedule development considering project deadline and resource constraints, and ( c) it incorporates improved schedule presentation that shows crews’ movements along the repetitive units and their detailed work assignments. The detailed formulation of the proposed model is described, and an example application is presented. The proposed model is demonstrated to offer significant advantages as a resource-driven approach. Future extensions to the proposed model are then outlined.
Evaluating Design-Build Procurement Documents for Highway Projects: How Good Are They?
Authors: Ernzen Jim , Vogelsang Ken
Published: April 2007

Recent innovations by the Arizona Department of Transportation in the use of design-build procurement for highway construction are presented. Explosive population growth in Arizona has pushed the department to the limits of its capacity and challenged it to develop innovative ways to stretch its resources to meet the constituents’ needs. In 1996 the department spearheaded the passage of a pilot design-build law aimed at completing public construction projects more rapidly than could be done using traditional methods. An evaluation made of the procurement documents used for the second design-build project in this pilot program is described. The project reconstructed an extremely congested 12.9-km (8-mi) segment of Interstate 17, a primary artery carrying 180,000 vehicles per day through the city of Phoenix, widening it from 6 lanes to 10. The department used a two-step method for the selection of the winning design-build team from both a request for qualification and a request for proposal. Both documents were evaluated for the clarity of thought and the fairness of the point distribution methodology used by the selection teams. The responding teams were also surveyed about their costs expended during the proposal process. The primary method of data gathering was by written survey of all the proposing teams followed by unstructured interviews with responding principals. Analysis of the data gathered clearly showed the areas in which the procurement documents were unclear and in which the department needed to make corrections for future projects.
Commuter Rail Station Governance and Parking Practices
Authors: Wilcock David C.
Published: April 2007

The station governance and parking practices of 19 commuter rail services in the United States and Canada are summarized. Unique or innovative approaches to address ownership and management issues are described. Unlike most urban transit systems, commuter rail authorities often do not control stations or parking. Wide-ranging practices exist, from outright facility ownership and control by the authority to no ownership or control. Many agencies and the private sector, including freight railroads with several services, are involved in ownership and management. Older, more established systems have the most complex ownership arrangements and operating practices. The authority, municipalities, and private sector of many systems are involved in the ownership and management of station buildings and parking facilities. Many authorities continue to provide ticket agents at stations, and a fee is typically charged for parking, which is often collected by the municipality. Passenger platforms are generally owned and maintained by the authority. Newer commuter rail services have less complex practices. Sometimes the authority is not involved with the station building or parking, although it typically owns and maintains the platforms. Many newer services also use technology more extensively, including ticket vending machines, to reduce the need for station personnel. Parking at the newer systems is generally provided free of charge, although various ownership and operating arrangements exist. Several systems have developed innovative approaches to address parking capacity issues. Partnerships with municipal governments, private companies, and community organizations to share parking are also used to reduce agency expenditures for new parking.
Modeling Response to Parking Policy
Authors: Shiftan Yoram , Burd-Eden Rachel
Published: April 2007

Parking policy is one of the most powerful means urban planners and policy makers can use to manage travel demand and traffic in city centers. Since urban access is considered crucial to the economic success of a downtown area, certain constituencies, such as business and retail, have historically been opposed to any parking-restriction policies. To address these concerns and create appropriate parking policies, it is important to understand how visitors to the city center are likely to respond to new policies. A model to estimate the likely response to two parking-policy alternatives in the Carmel Center area of Haifa, Israel, is presented: an increase in parking cost and a decrease in parking availability that will increase driver search time for parking. The model is based on the responses of center visitors to a stated preference survey. Three different models were estimated: a binary model, a multinomial logit, and a nested model. The results show that workers are more likely to change their mode or time of day of travel than to change destination or cancel their activity. Nonworkers are likely to make all types of changes, and for all policies, they are more sensitive than workers. These results suggest that parking measures may be effective in reducing congestion in the business district. However, they may also have a negative effect on the vitality of the business district as shoppers and other visitors are likely to go to other places in response to the change.
Proximate Commuting: Hype or Potential? An Evaluation
Authors: Rodríguez Daniel A.
Published: April 2007

Proximate commuting is a potential employer-based travel-demand management program under which large, decentralized employers reassign each voluntary participant to a job location (with the same employer) closer to the participant’s residence to reduce commuting distances. Key to determining proximate commuting’s feasibility and potential success are the identification and estimation of its commuting benefits. A model for quantifying the distance and time savings of proximate-commuting programs is presented. It relies on stated preference information regarding an employee’s willingness to proximatecommute. Potential commuting savings are modeled as originating from two distinct sources. First, savings can stem from mutually beneficial job exchanges that are estimated using optimization tools. Second, due to job vacancies occurring over time, savings can result from future employee relocations to closer branches. Because predicting future job vacancies is inherently stochastic, savings from future vacancies are estimated using optimization tools on scenarios created by a Monte Carlo simulation. The model is implemented and tested using data from selfadministered survey questionnaires distributed among all tellers of a single banking institution in Bogotá, Colombia. Results suggest immediate savings of 1,700 h/year and average savings of more than 8,000 h after the second year of program implementation. These results highlight the fact that accommodating people’s desires for shorter commutes at negligible cost is possible and suggest a cautiously optimistic outlook for proximate commuting. Future research should focus on proximatecommuting implementation issues, such as employer adoption, middle management’s role, and employee satisfaction after relocation.
Techniques for Determining Errors in Asphalt Binder Rheological Data
Authors: Marasteanu Mihai O. , Anderson David A.
Published: April 2007

Numerous new methods for specifying asphalt binders, based on more complex theoretical approaches, have emerged in the past years, and researchers are increasingly using these methods for studying asphalt binders. These methods require an increased degree of accuracy and precision in the laboratory data. A number of simple techniques are detailed that can be successfully used to identify errors in rheological data obtained for asphalt binders. Asphalt binders do not exhibit sudden changes in their behavior with respect to time or temperature. Therefore, any discontinuities revealed by the visual inspection of the test data in graphical format can be attributed to testing errors. A powerful yet simple tool in identifying potential problems with the dynamic shear rheometer test data is the Black diagram. The Black diagram is a plot of phase angle versus log | G*|, which, unlike master curves, does not require shifting of the data generated at different temperatures. However, pseudo Black diagrams should not be used with the bending beam rheometer (BBR) data because of the errors in calculating m-values associated with the use of the polynomial approximation. The c-coefficient can be used for a quick check of BBR data on the basis of the fact that the slope of the m-values decreases as the test temperature decreases. For the direct tension test, the secant modulus calculated from the stress-strain data provides a better tool to identify errors in the test data.
Conversion of Weight of Freight to Number of Rail Cars
Authors: Hancock Kathleen L. , Sreekanth Ande
Published: April 2007

Multimodal freight vehicle assignment models require numbers of vehicles to generate origin-destination matrices. Most current freight flow data are provided as total volume or value. Presented are the development and results of conversion models for converting weight to number of rail cars as one component of a multimodal planning activity. The 1992 rail waybill sample was used for developing the conversions. Only loaded cars were used for conversions. Therefore, empty cars are not included in the models. Evaluation of these conversions was performed by using 1993 Commodity Flow Survey data. On the basis of the evaluation, recommendations on conversion models are made.
Overview of Freight Flow Databases in South Africa
Authors: Page Oliver
Published: April 2007

Freight flow databases and their development have had a checkered history in South Africa. The private and public sectors both accept that such a resource is needed, and numerous attempts have been made to establish one. However, there is no freight flow database that fulfills all needs potential users would have. An overview of the status quo of freight flow databases in South Africa is given. The organizations involved in development of this resource are identified. An understanding of why longterm sustainability of freight flow databases has not been achieved is presented through an exploration of the shortcomings faced by agencies wanting to establish such a resource. The challenges that could affect the success of freight flow databases are presented. It is concluded that the development of freight flow databases has passed its initial stages, and the need for establishment of an all-inclusive database is evident. Nevertheless, agencies involved in freight flow database development have been negatively affected by increased competition for fewer resources. Sustainable development, therefore, will require innovative approaches for establishing freight flow databases, potentially through maximizing the application of information technology.