bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Infrared Ignition Furnace for Determination of Asphalt Content
Authors: Hurley Graham C. , Prowell Brian D.
Published: April 2007

The Troxler Model 4730 infrared ignition furnace was compared with a standard Thermolyne ignition furnace. Comparisons conducted with a single unit of each furnace type were based on the correction factor for aggregate loss during ignition, accuracy, and the variability of the measured asphalt content and aggregate degradation during ignition. Forty-eight samples representing two nominal maximum aggregate sizes (9.5 and 19.0 mm), four aggregate types (granite, crushed gravel, limestone, and dolomite), and two asphalt contents (optimum and optimum plus 0.5% asphalt content) were tested in each furnace. The results indicated that the correction factors for aggregate loss during ignition were significantly different for each type of furnace, thus requiring a separate calibration for each type of furnace. In practical terms, the differences for all but the 9.5-mm nominal maximum aggregate size (NMAS) limestone and both dolomite mixtures were less than 0.1%. The samples with the optimum plus 0.5% asphalt content were tested by using the calibration factors developed for a particular mix–furnace combination. The results were analyzed in terms of accuracy (bias) and variability (standard deviation). Neither the measured biases nor the standard deviations for the two types of furnaces were significantly different. The results obtained with four sieve sizes (NMAS and 4.75, 2.36, and 0.075 mm) were evaluated for aggregate breakdown. A comparison of the aggregate gradations recovered from both furnaces indicated no significant difference in the degree of aggregate degradation. A round-robin investigation should be conducted to confirm that the precision of the infrared furnace is similar to the precision of the standard furnace.
Construction Contract Quality Warranties: Hybrid Quality Assessment Model
Authors: AbdelRazig Yassir , Chang Luh-Maan
Published: April 2007

The term "quality" is defined as the conformance to predetermined requirements or specifications. These requirements may be simple or complex. They may be set in terms of the end result required or as a detailed description of how work should be executed. Recently, there has been increasing interest in quality assurance in the construction industry. Most current techniques used in infrastructure assessment and quality inspection rely merely on subjective criteria. Such inaccurate or subjective assessment techniques have been identified as critical obstacles to effective infrastructure management. An overview of contract quality warranties for steel bridge coatings is presented as a practical example, and a hybrid assessment model that can be used to quantitatively measure quality attributes is proposed. The hybrid model combines image processing and neural networks for defect (specifically, rust) recognition and measurement and uses statistical analysis for quality acceptance or rejection on the basis of the contract warranty clauses. The hybrid model incorporates human experience through the training stage to benefit from experts’ knowledge and to correct for other external factors.
Successful Application of Ground-Penetrating Radar for Quality Assurance-Quality Control of New Pavements
Authors: Al-Qadi Imad L. , Lahouar Samer , Loulizi Amara
Published: April 2007

The successful application of ground-penetrating radar (GPR) as a quality assurance–quality control tool to measure the layer thicknesses of newly built pavement systems is described. A study was conducted on a newly built test section of Route 288 located near Richmond, Virginia. The test section is a three-lane, 370-m-long flexible pavement system composed of a granular base layer and three different hot-mix asphalt (HMA) lifts. GPR surveys were conducted on each lift of the HMA layers after they were constructed. To estimate the layer thicknesses, GPR data were analyzed by using simplified equations in the time domain. The accuracies of the GPR system results were checked by comparing the thicknesses predicted with the GPR to the thicknesses measured directly from a large number of cores taken from the different HMA lifts. This comparison revealed a mean thickness error of 2.9% for HMA layers ranging in thickness from 100 mm (4 in.) to 250 mm (10 in.). This error is similar to the one obtained from the direct measurement of core thickness.
Toward a Comprehensive Policy of Nighttime Construction Work
Authors: Holguín-Veras José , Ozbay Kaan , Baker Robert , Sackey David , Medina Angel , Hussain Sajjad
Published: April 2007

A first approximation toward a comprehensive policy of nighttime construction work based on the explicit consideration of the following three main aspects is presented: ( a) the travel time savings produced by nighttime construction work, ( b) the impact that nighttime work has on worker’s human factors (e.g., sleep deprivation and disruption of family and social lives), and ( c) the impact that pay differentials for nighttime workers would have on project costs. Other aspects such as quality of work and inspection were not studied because of project constraints. The travel time and economic savings of nighttime work were estimated by means of traffic simulations for a typical case. The human factor analyses relied on field surveys and interviews with workers. This research found ample evidence that indicates that nighttime work produces ( a) negative impacts on the workers’ sleep patterns, body rhythms, and social and family lives and ( b) significant economic savings in terms of travel time to motorists. A set of policy recommendations is discussed and analyzed.
Maintenance of Hypertext-Based Specifications for State Highway Projects
Authors: Walters Russell C. , Li Lifeng
Published: April 2007

The performance of construction projects heavily depends on how well information is managed. In Iowa the management of this information means locating details and tracking changes in several printed volumes that define design details, material specifications, construction methods, and testing procedures. The details of the development of an electronic reference library (ERL) that provides a virtual library for construction design and management of state highway projects in Iowa are provided. ERL is a large document containing more than 25,000 hyperlinks and is updated and distributed twice a year. The details described include the development of the initial prototype, training of existing staff to maintain an electronic document, and issues related to the production of biannual updates. The major challenges for the development of an ERL include determination of the user interface, document selection, reproduction of accurate content, and maintenance of the electronic version.
Evaluation of Effects of Centerline Rumble Strips on Lateral Vehicle Placement and Speed
Authors: Porter R. J. , Donnell Eric T. , Mahoney Kevin M.
Published: April 2007

Transportation agencies are using a variety of rumble strip patterns to improve highway safety. Previous studies have documented the efficacy of rumble strips in reducing certain crash types. However, no research has been published on the operational effects of these low-cost safety treatments. An evaluation of the effect a treatment has on operational characteristics can be conducted and reported in much less time than an evaluation based on crash data. The effect of centerline rumble strips on lateral vehicle placement and vehicle speeds on two-lane highways was investigated with a before-and-after observational study. Data were collected using tape switches at two treatment sites and two comparison sites. The lane widths were 11 and 12 ft. Data analysis and statistical testing indicated the centerline rumble strips had a significant effect on the mean and variance of lateral vehicle placement at both treatment sites. The observed change in the mean lateral vehicle location was away from the centerline rumble strips at both treatment sites; the variance of lateral vehicle location decreased at both sites. Data collected at the corresponding comparison sites during the before-and-after periods indicated no change in the mean and variance of lateral vehicle placement. Additionally, the study found that lateral vehicle placement in travel lanes may not be normally distributed as was previously assumed. Further evaluation of lateral vehicle placement distribution should be conducted with larger sample sizes and different roadway cross sections. No relationship could be drawn between speed and the presence of rumble strips for 11- or 12-ft lanes.
Traffic Sign Luminance Requirements of Nighttime Drivers for Symbolic Signs
Authors: Schnell Thomas , Aktan Fuat , Li Changbao
Published: April 2007

An experiment was designed to determine the luminance contrast and background luminance requirements for recognition of negative contrast symbol signs (black on yellow) under low-adaptation luminance conditions. The effects of background complexity (two levels), symbol type (four symbols), background luminance (five levels), and luminance contrast between the symbol and its immediate sign background (six levels) were studied. The experiment was conducted in the Traffic Sign Simulator Facility of the Operator Performance Laboratory at the University of Iowa. Participants walked toward a calibrated, fixed-size sign stimulus projected on a large projection screen in the study. Two levels of performance were assessed: maximum recognition distance (threshold) and the distance at which the symbol types could be recognized with ease (confident). A total of 40 subjects, half of whom were young and half older, participated in the study. The traffic sign background luminance, luminance contrast, and symbol type were found to be statistically significant in affecting the symbol recognition distance. Observer age and background complexity were statistically nonsignificant. The difference between the threshold and confident viewing distances was also significant. The recognition performance data of four symbols is presented in terms of the visual angles subtended by the heights of the symbols for the six levels of contrasts and the five levels of background luminances.
Fog Luminance Evaluation in Daytime
Authors: Paulmier Giselle
Published: April 2007

In daytime, fog creates a luminous veil that impairs the visual indices required by motorists to coordinate their task of driving. The level of fog luminance depends on many parameters. A method is described to compute the luminance of a fog layer on the basis of its optical depth, the droplet size distribution, and the relative position of both the sun and the motorist. The results are then analyzed and indicate that fog luminance depends to a great extent on the direction of observation with respect to the sun. Except when the motorist is traveling toward the sun, the fog luminance follows the variations of horizontal illuminance, which increases with the altitude of the sun yet decreases with droplet size distribution. In most instances, the influence of the optical depth calculated over the height of the fog layer remains small. Only when facing the sun in a fog with droplet diameters less than or equal to 1 μm does the luminance increase significantly as optical depth decreases. The impact on the visibility parameters is presented.
Validation of Photometric Modeling Techniques for Retroreflective Traffic Signs
Authors: Carlson Paul J. , Urbanik Thomas
Published: April 2007

Recent research in the United States has focused on the development of minimum retroreflectivity levels for traffic signs. The engineered approach uses a supply luminance versus demand luminance concept to achieve a metric that can be used to set minimum retroreflectivity levels. The supply luminance depends on reliable modeled estimates of headlamp illuminance reaching traffic signs and the resultant luminance directed back toward the driver. While the science behind the photometric modeling process is fundamentally sound, a small pocket of literature shows inconsistent relationships between measured and modeled illuminance and luminance levels. A systematic validation study of photometric modeling was done with field measurements made under conditions identical to those that were modeled. A set of headlamps were photometrically measured along with three different samples of retroreflective sign sheeting materials. Illuminance and luminance levels were then modeled for nine sign positions and three vehicle types. Then field illuminance and luminance were measured using the same scenarios, headlamps, and retroreflective sign sheeting materials. The field measurements were recorded once on a concrete pavement and once on an asphalt pavement. Both sets of field measurements also included baffled and unbaffled measurements so the impact of pavement reflection could be considered. Photometric modeling techniques of nighttime traffic sign performance compared well with field measurements made under identical conditions. The maximum illuminance difference was 16% and was attributed to the pavement reflection properties. The maximum luminance difference was only 2.4%. The retroreflective performance of traffic signs redirects most of the pavement reflection back toward the pavement. Therefore, estimates and measurements of luminance are less affected than illuminance.
Comparing Operating Characteristics of High-Speed Rail and Maglev Systems: Case Study of Beijing-Shanghai Corridor
Authors: Liu Rongfang (Rachel) , Deng Yi
Published: April 2007

The need for high-speed ground transportation systems (HSGT) has become more urgent than ever, evidenced by congestion in both urban and intercity travel. Congestion problems are no longer confined to densely developed urban areas or industrialized countries but also spread into suburban regions and developing countries. Characterized by high speed, operating reliability, passenger riding comfort, and an excellent safety record, HSGT presents a vital solution for our congestion problems, intercity or urban. There are two distinguished technologies under the general HSGT umbrella: high-speed rail (HSR) and magnetic levitation (Maglev). Sharing some common characteristics of HSGT, such as very high speed and riding comfort, these two technologies are dramatically different in guideway requirements, propulsion sources, operating characteristics, environmental impacts, and costs. Ongoing debates among the academic community have not presented any strong evidence to favor one over another in lieu of specific corridor alignment. A focus is on the engineering comparison of HSR and Maglev systems and their potential implementation in the Beijing and Shanghai corridor. It is undeniable that cost, political will, and social and cultural acceptance play vital roles in the eventual realization of any technology. An emphasis is on the overview of technology, comparison of operating characteristics of HSR and Maglev, and the implications of their potential application in a 1,300-km-long corridor from Beijing to Shanghai—the top economic, population, and culture engine in China.
Dynamic Considerations in the Design of High-Speed Railway Bridges
Authors: Willford Michael , Hicyilmaz Kubilay , Pratt Karl
Published: April 2007

Research was done concerning the dynamic performance checks required for bridges carrying high-speed rail traffic, and it presents practical numerical simulation techniques for the prediction of performance at the design stage. The sensitivity of the predictions to different modeling assumptions is illustrated. The procedures are described in the context of an example structure, a four-span continuous steel-composite bridge for the new Channel Tunnel Rail Link in southern England. This structure was analyzed with the proposed method, and its dynamic performance has subsequently been measured in the field. The dynamic properties of the bridge and the vibrations predicted at the design stage are compared with measurements made during commissioning tests with Eurostar trains at speeds of up to 300 km/h (190 mph). The principal dynamic concerns relate to dynamic load factor for the structural design, ballast stability, carriage acceleration, and radiated noise. The simulation method is shown to provide realistic predictions.
Behavior of Railway Bridges and Other Railway Infrastructure in Three Strong to Great Earthquakes in 2001
Authors: Byers William G.
Published: April 2007

In 2001, earthquakes in January (magnitude 7.7 in Gujarat, India), February (magnitude 6.8 near Nisqually, Washington), and June (magnitude 8.4 near Atico, Peru) damaged railroads. Their effects on railroad infrastructure, considered both in isolation and in comparison with other effects on railroad operations, are of interest to engineers with responsibility for railroad bridges and other railroad maintenance in seismically active regions. Although the overall effects on railroad operations were correlated with earthquake magnitude, damage to structures appeared more closely related to local conditions and details of design and construction. Track and roadbed damage resulted from settlement, slides, and rock falls. It was correlated with magnitude in both severity and extent and caused the most significant effect on operations in both the Gujarat and Atico earthquakes. Damage to railroad bridges included minor displacement of steel girder spans, cracking of joints in masonry piers and arches, separation of wing walls from abutments, collapse of masonry spandrel walls of arches, rotation and displacement of a framed dump bent in a timber trestle, and movement of piers of an open bascule span that prevented closing of the span. Damage to tunnels was minor. As for other railroad structures, there was widespread damage and destruction of masonry buildings, severe damage to a pedestrian viaduct over a railroad yard in India, significant damage to railroad buildings in Seattle from the Nisqually earthquake, and minor damage to buildings in Peru.
Canadian National Railway Experience with 136-lb Thick Web Rail Switch Points
Authors: Peters Nigel
Published: April 2007

In 1999, Canadian National Railway was the first Class 1 railroad to move away from switch points with reinforcing straps and introduce the use of thick web rail into all its 136-lb turnouts. A review of the history of reinforcing straps on switch points in North America indicates that this is an obsolete practice carried on unnecessarily. The moment of inertia of a 136-lb thick web rail is nearly 2.5 greater than that of the European Zu1-60 asymmetrical thick web section, which has performed so well in tangential geometry turnouts in North America. The advantages of adopting the 136-lb thick web rail section as a standard for use in switch points is one of economy, primarily related to the labor savings in the fabrication of the switch point.
Increasing Speeds Through the Diverging Route of a Turnout Without Increasing Lead Length
Authors: Bonaventura Clifford S. , Zarembski Allan M. , Palese Joseph W. , Holfeld Donald R.
Published: April 2007

Presented are the results of Phase I of an FRA-sponsored study on low-cost means to increase safe speeds through turnouts by way of a retrofit or upgrade. Turnout lead length and frog angle were considered fixed, eliminating costs in relocating the frog or switch points. After in-depth research and dynamic simulation testing, it was determined that the best approach was to optimize existing American Railway Engineering and Maintenance of Way Association (AREMA) turnout geometry. This required a new diverging switch rail and reshaping both the curved stock and closure rails. This low-cost modification applies to most existing turnouts and is expected to improve ride quality and decrease wear without detriment to current maintenance practices. The optimization of a conventional AREMA #20 turnout with straight switch points is discussed as an example. The best vehicle performance in simulations was achieved by a design having a very low entry angle. Vehicle behavior at a speed of 51 mph was significantly improved over the AREMA straight point design at its speed limit of 36 mph, as well as that of the AREMA curved point design at its limit of 50 mph. Also, simulated vehicle performance was nearly as good as for a #20 tangential turnout that has a 20 ft longer lead length. Finally, there was improved performance at speeds as high as 60 mph without exceeding any established safety limits. From these results, a turnout with the reshaped geometry has been constructed and is scheduled for installation on New Jersey Transit.
Development and Implementation of a Continuous Vertical Track-Support Testing Technique
Authors: Li Dingqing , Thompson Randy , Marquez Previn , Kalay Semih
Published: April 2007

As part of an Association of American Railroads (AAR) research program, the Transportation Technology Center, Inc., a subsidiary of AAR, has developed a new method using its track loading vehicle (TLV) technique to measure vertical track deflections under given vertical loads while in motion. The technique was developed to identify weak track locations and to measure the load-carrying capacity of existing tracks to aid and prioritize track maintenance and to improve railroad operational performance. Discussed are the development and implementation of this continuous vertical track-support measurement technique. This technique provides an in-motion and nondestructive means of testing vertical track support. Currently, this newly developed TLV technique is being used in revenue service to identify large track stiffness variations along the track, indicating lower track strength or abrupt transitional stiffness changes. It is also used to locate the source of lower strength due to ballast and subgrade conditions, as well as to assess the need for upgrades to accommodate higher operation speeds or heavier axle loads. Extensive tests in revenue service have shown this TLV testing technique to be a viable method to perform the above tasks successfully. In addition, this new test technique can be used to improve the understanding of track strength degradation over time and to help direct limited maintenance resources to track locations requiring near-term maintenance.
Railroad Accident Rates for Use in Transportation Risk Analysis
Authors: Anderson Robert T. , Barkan Christopher P. L.
Published: April 2007

Annual safety statistics published by FRA provide train accident counts for various groupings, such as railroad, accident type, cause, track type and class, train length, and speed. However, hazardous materials transportation risk analysis often requires more detailed accident rate statistics for specific combinations of these groupings. The statistics that are presented enable more precise determination of the probability that Class I and non-Class I railroad freight trains will be involved in an accident on various classes of main-line track. An increase in the overall accident rate from 1997 to 2001 can be largely attributed to the increase in yard accidents. During that time, the main-line derailment rate for Class I freight trains remained nearly constant. Track class-specific derailment rates for Class I main-line freight trains show two orders of magnitude difference between the lowest and highest FRA track classes. Depending on the risk analysis question, accounting for these differences in rates will often be important in developing an accurate estimate of risk over the length of a route or at particular locations along a route. A sensitivity analysis suggests that the distribution of freight train miles by FRA track class may have changed since a study conducted by the Association of American Railroads in the early 1990s. More up-to-date estimates of track class-specific accident rates would require new data on this distribution.
Value Pricing Outreach and Education: Key Steps in Reaching High-Occupancy Toll Lane Consensus in Minnesota
Authors: Buckeye Kenneth R. , Munnich Lee W.
Published: April 2007

Since 1994, Minnesota transportation policy leaders have made several attempts to implement a value pricing project in the Twin Cities area. A joint effort involving the Minnesota Department of Transportation, the Metropolitan Council, and the University of Minnesota's Hubert H. Humphrey Institute of Public Affairs has led to an increased awareness by transportation, political, business, environmental, and other community leaders that variable road pricing is integral to a long-term congestion management strategy. In 2003 the Minnesota state legislature with the support of the governor and lieutenant governor passed legislation allowing user fees for single-occupant vehicles in high-occupancy vehicle lanes. Minnesota is considering the implementation of express lanes, also known as high-occupancy toll lanes, on I-394 as the first test bed for value pricing in Minnesota. Minnesota's education and outreach efforts offer lessons for other states and regions considering value pricing projects: local political champions are critical for the success of any value pricing effort; a communications strategy is necessary to make sure that a range of public interests is addressed; an initial demonstration project must be both technically and politically feasible; and a long-term approach undeterred by short-term setbacks is essential.
Role of Hypothecation in Financing Transit: Lessons from the United Kingdom
Authors: Enoch Marcus , Potter Stephen , Ison Stephen , Humphreys Ian
Published: April 2007

Two hypothecated charges to fund local public transport have recently passed onto the statute books in the United Kingdom. The first is road user charging, with London and Durham the first to be implemented, and the second is a workplace parking levy. The use of such local hypothecated (or "earmarked") mechanisms is not new. A variety of such charges, local taxes, and levies have been in use for decades to fund public transport and (less frequently) as a tool for transport demand management in the United States, Germany, Austria, Portugal, Scandinavia, India, and Singapore. In the general debate about the two new hypothecated charges in the United Kingdom, this international experience has been largely neglected. The aim is to detail a related and equally neglected area, namely, the local hypothecation of charges to fund public transport improvements in Britain. Under existing legislation it has been possible for some local authorities to dedicate revenue streams from sources such as parking charges and planning gain to develop and improve public transport services. There is also significant experience of dedicated revenue streams in the private sector, for example, at airports. Examples of the British experience of hypothecation are detailed, and their lessons for the new and more radical measures that are now being considered are examined.
Evaluation of Nationwide Differential Global Positioning System for Assessing Road User Charges
Authors: Cheng Pi-Ming , Donath Max , Ma Xiaobin , Shekhar Shashi , Buckeye Kenneth
Published: April 2007

Advances in alternative fuel technologies and increasing motor vehicle fuel efficiency may result in a decline or flattening of demand for conventional fuels in the United States in the coming decades. One outcome of this development may be a reduction in state and federal income from motor fuel taxes, the primary source of funding to maintain and improve the transportation infrastructure. To keep pace with future transportation needs, a new funding mechanism is needed to supplement or replace the current road financing mechanism. One possible approach is to charge for road use based directly on a measure of travel on public roadways by using onboard computers coupled with the Global Positioning System (GPS) and digital maps. The main goal of this research was to develop the system requirements for the GPS component that would determine the vehicle's location on a given roadway with an in-vehicle road user charging system. The focus was to evaluate the GPS in the most difficult of environments—locations in which roads of different jurisdictions and possibly different fee structures are located in proximity to each other. To be effective, the system must be able to place the vehicle on the correct road. A description is given of a methodology to specify the needed accuracy of a GPS receiver to meet a required accuracy in distinguishing roads with a given separation distance at a statistical level of confidence. Results are reported for a series of road-based experiments that were performed to evaluate GPS receivers that use the nationwide differential GPS service.
Jurisdiction Shopping Among Apportioned Motor Carriers: Examination of Causes and Potential Remedies
Authors: Ojah Mark
Published: April 2007

Jurisdiction shopping refers to the practice of interstate motor carriers searching for the cheapest, most convenient jurisdiction in which to register their heavy trucks. In the past 10 years this activity has contributed to the geographic redistribution of tens of thousands of truck registrations in the United States. Some jurisdictions have lost millions of dollars in registration-related revenue as a result. Unlawful registration practices have been responsible for a considerable amount of jurisdiction shopping. However, state discrepancies in registration costs and convenience have prompted some trucking firms to engage in a legitimate form of jurisdiction shopping. States wishing to preserve their carrier registration base and associated revenue must ensure that all fees and taxes assessed on local registrants are fully apportioned to out-of-state carriers operating in the jurisdiction. In addition, a convenient carrier-credentialing regime must be provided. That entails joint administration of related interstate programs and the development of unified, streamlined processing systems that minimize registrant costs and administrative burden. Finally, the provision of a broader range of registration options, such as online registration renewal and fee payment, should be explored. These strategies will help reduce the negative consequences of jurisdiction shopping and ensure that states receive a fair share of interjurisdictional truck registration revenue.
Life-Cycle Cost Analysis: State of the Practice Versus State of the Art
Authors: Ozbay Kaan , Jawad Dima , Parker Neville A. , Hussain Sajjad
Published: April 2007

Life-cycle cost analysis (LCCA) is increasingly gaining recognition by the transportation community as an indispensable practice if the sustainability of its infrastructure systems is to be realized. The product of a 3-year study that assessed the LCCA practice in state highway agencies (SHAs) is presented. The study examined how LCCA practice changed in two decades, surveyed the way LCCA is practiced currently at SHAs in the United States, and reviewed how this evaluation technique is deliberated by the academics and researchers in the engineering and economics domains. Results of this study prove noteworthy in the inspection of an observed gap between the state of the practice and state of the art of LCCA. After all, that gap set up grounds for the noted mistrust in the credibility of LCCA. In addition to study results, an analysis of the observed gap and its causes is presented as well as recommendations for what can be done to bridge that gap. It is hoped that this will prove valuable for practitioners conducting LCCA, for policy makers, and for researchers carrying out studies on various topics related to LCCA.
Empirical Study of Economic Spillovers of Interstate 105 in Los Angeles County
Authors: Chalermpong Saksith
Published: April 2007

Many researchers agree that at this time new investments in highways in the United States have little impact on overall growth in output. New highways play a more important role in shifting economic activities among places, drawing jobs from other locations into the highway corridors—a phenomenon known as negative spillovers. Testing the hypothesis of economic spillovers of highway investment at the metropolitan level is the objective. Empirical tests of the spillover hypothesis are conducted with census tracts as the unit of observation. Results of the quasi-experiment reveal census tract employment growth patterns that confirm the existence of negative spillovers caused by the 1993 opening of Los Angeles County's Interstate 105. The benefiting area, which is limited to a long narrow corridor around the highway, grew substantially after the highway was opened, while nearby locations outside the corridor experienced slow growth relative to the rest of the metropolitan area, after controlling for various factors. These results show that negative spillovers from new highways are present not only at the aggregate geographic level, such as states or counties, as demonstrated in the literature, but also at the highly localized level, that is, in a metropolitan area.
Infrastructure Development in Germany Under Stagnating Demand Conditions: A New Paradigm?
Authors: Zumkeller Dirk , Chlond Bastian , Manz Wilko
Published: April 2007

Findings from various sources of information, such as mobility panels, permanent road traffic recording devices, and model calculation methods, indicate that for the past few years passenger traffic demand in Germany has not been increasing but has shown notable evidence of stagnation. An analysis of various relevant factors clarifies that this has in fact been an emerging tendency. This is true especially with respect to the demographic changes in Germany and the increased probability of more scarce and definitely more expensive oil resources; further stagnation of traffic demand appears imminent. That leads to the conclusion that infrastructure development must not be based on the idea of everlasting growth with expansions in areas in which the symptoms of traffic growth have been most obvious. It will rather be necessary to identify accurately specific areas of growth or stagnation and to find a suitable scale for further development. Future planning should concentrate on modification rather than on expansion of infrastructure facilities.
Using Multiple Assessment Levels for Evaluating Transportation Demand Management Projects: Monitoring and Evaluation Toolkit
Authors: Finke Timo , Schreffler Eric N.
Published: April 2007

Many efforts to evaluate the effectiveness of a transportation demand management (TDM) project focus on either ( a) the ability to get information to travelers to have them consider switching to more sustainable modes or ( b) the impact of mode changing on travel and air quality. The former type of evaluation is sometimes called soft evaluation (awareness of services offered, inquiries for information, etc.), and the latter is called hard evaluation (trip, vehicle miles of travel, and emission reduction). A large-scale demonstration program funded by the European Commission, called mobility strategies for the next decades (MOST), developed a standardized monitoring and evaluation toolkit (MET) to aid those implementing "mobility management" projects in evaluating all types of impacts and project results. This was achieved by enumerating assessment levels that ranged from awareness to system impacts. The state of the practice in TDM evaluation is discussed; the MOST-MET is introduced; an example of its use with a specific TDM project evaluation is provided; and then the transferability of the MET and its assessment levels to other types of TDM evaluation (beyond pilot projects) is considered.
Methodology for Regional Survey of Mode Switching from Voluntary Mobile Emission Reduction Programs
Authors: Diggins Lori , Schreffler Eric , Gregory Jennifer
Published: April 2007

A regional survey methodology to estimate reductions in vehicle miles traveled and in emissions resulting from commute changes attributed to voluntary mobile source emission programs is described. This "switcher survey" determined the incidence of switches to alternative modes among commuters in the Atlanta metropolitan region and collected information about their travel before and after the changes were made. Researchers encountered many methodological issues relevant for other transportation demand management (TDM) evaluations, particularly those assessing emission reductions from regional TDM strategies. The survey methodology is described; issues addressed during the survey are discussed; and analysis implications of the issues are presented. The research was conducted, in part, to test the ability of the survey for this purpose. Several survey modifications are suggested to improve the survey and increase its flexibility for use in a variety of evaluation situations.
Effects of Standard Enforcement on Safety Belt Citations in Michigan
Authors: Kostyniuk Lidia P. , Eby David W. , Molnar Lisa J. , Miller Linda L.
Published: April 2007

A study investigated the effects on safety belt citations of the change in police enforcement of Michigan's mandatory safety belt law that went into effect on March 10,2000. Safety belt citation records were obtained from Michigan courts for one full year before and one full year after the change from secondary to standard enforcement. Analysis of the records indicated an overall increase of 9% in safety belt citations and an 8% increase in the number of individuals cited. No effects from the change to standard enforcement were found for the distribution of safety belt citations by sex, age, and race, overall, or for both day- and nighttime periods. The proportion of persons receiving multiple safety belt citations in one year remained at 11%, and the average number of citations per cited person remained at 1.1 per year. Individuals who continued to receive citations after standard enforcement were more likely to be males age 16 to 22. No effect on the number of child-restraint citations was found. Changes in the disposition of cases included an increase in the proportion of guilty outcomes and a decrease in the proportion of cases dismissed.
Integrated Safety Management System and Iowa Safety Management System: Introduction to Workshop Results
Authors: Masliah Maurice , Bahar Geni , Parkhill Margaret
Published: April 2007

Introduced are the ideas found in the integrated safety management system (ISMSystem), published as National Cooperative Highway Research Program Report 501. The ISMSystem is founded upon the principle that aligning the activities of different agencies within a jurisdiction can result in a level of safety unobtainable by those agencies working independently and in decision-making isolation. In addition to providing highway safety benefits, implementing the ISMSystem should result in cost savings when the resources of different agencies are pooled and shared. The ISMSystem describes an organizational structure that includes a coalition of highway safety agencies that develops a common mission and vision at the highest level of management. Safety professionals with expertise in relevant emphasis areas are recruited into teams to address the specific goals set out by the coalition and in doing so produce action plans that integrate the activities of the implementing agencies. The integrated safety management process describes the process for going from crash data to integrated action plans to increase safety. A workshop introducing safety professionals to the ISMSystem and allowing multidisciplinary teams to practice developing strategies to address safety emphasis areas has been recently conducted in the state of Iowa. The key lessons from the Iowa workshop are summarized, including the need for setting quantifiable safety goals, the need for both horizontal and vertical agency integration, interaction among emphasis areas, and the types of issues the ISMSystem is designed to address.
Development of a Safety Resource-Allocation Model in Michigan
Authors: Kar Kohinoor , Datta Tapan K.
Published: April 2007

Traffic crashes, injuries, and fatalities on roads and highways are of great concern to safety professionals in the United States. These problems are often caused by infrastructure inadequacies, increasing traffic, and inappropriate driver behavior. Reduction of traffic crashes and injuries is possible if an effective statewide safety-improvement program is implemented. Development of such a program requires careful investigation and analysis of historical traffic-crash data and use of an intelligent resource-allocation strategy. A statewide traffic-crash analysis was performed with crash and exposure data for the entire state of Michigan. Typically, the resources available for safety projects and programs are not sufficient to undertake a comprehensive set of safety initiatives for the entire state. Therefore, it is important that the available resources are used optimally to achieve the greatest overall safety benefits. The Office of Highway Safety Planning (OHSP), a division of the State Police Department of Michigan, provides funding to local governmental agencies for a variety of safety projects and programs to alleviate traffic crashes and injuries. Most of the projects funded by OHSP involve safety initiatives related to alcohol, the use of safety-restraint systems, enforcement of traffic regulations, and programs related to driver behavioral issues. A comprehensive analysis of traffic crashes and injuries was performed with the past five years' crash data for all 83 counties in the state of Michigan. The high-priority areas for implementing safety initiatives in the state were identified and prioritized through a safety performance index (SPI) developed as a part of this research. The SPI involves the use of historical crash data and multiple exposure variables. The development, analysis, benefits, and uses of SPI are described. Based on the SPI values, development of an optimal resource-allocation model using linear programming techniques is also presented.
Overheight Vehicle Collisions with Highway Bridges
Authors: Fu Chung C. , Burhouse J. Ross , Chang Gang-Len
Published: April 2007

The objective of this study was to assess the magnitude of overheight vehicle collisions with highway bridges that caused structural damage, injuries, and sometimes even fatalities at both the Maryland and the national levels. The seriousness of the collisions was exemplified by a case in 1999 in which a truck hauling an overheight excavator struck and collapsed a pedestrian bridge over the Baltimore Beltway, killing one motorist and injuring three others. Statistics on overheight collisions in Maryland were collected from overheight vehicle detector records, the statewide accident database, and bridge inspection reports. An analysis of the data revealed that the frequency of overheight accidents reported in Maryland increased by 81% between 1995 and 2000. Of the 1,496 bridges susceptible to impact by overheight vehicles statewide, 309 (20%) have been struck, with 58 (4%) having required repairs. No nationwide databases on overheight collisions exist, so a survey was sent to each state to collect national statistics. Of the 29 states responding, 18 (62%) indicated that they consider overheight collisions to be a significant problem, but few were able to provide hard data.
Determining Life Expectancy of Preventive Maintenance Fixes for Asphalt-Surfaced Pavements
Authors: Bausano Jason P. , Chatti Karim , Williams R. Christopher
Published: April 2007

A large performance data set from in-service pavements was used in conducting a reliability-based analysis to determine the life expectancy (performance) of several preventive maintenance (PM) fixes. The distress index (DI)—the main pavement performance indicator used by the Michigan Department of Transportation—was used in the analysis. Probability distributions of DI values were developed at successive years after the PM application for five fixes: nonstructural bituminous overlay, surface milling with a nonstructural bituminous overlay, single chip seal, multiple-course microsurfacing, and bituminous crack seal. Reliability tables were then developed to express the probability that a given PM treatment would reach the performance threshold after n years; these tables therefore provide the pavement life expectancy for a given PM treatment at various reliability levels. A highway agency can use these tables to select PM strategies on the basis of expected life extensions.
Development of Preventive Maintenance Decision Trees Based on Cost-Effectiveness Analysis: An Ontario Case Study
Authors: Wei Changjun , Tighe Susan
Published: April 2007

Various transportation agencies have begun to consider implementing preventive maintenance (PM) strategies as part of their regular pavement management programs. To determine whether a PM strategy is more cost-effective than a conventional maintenance strategy, various technical and economic analyses were carried out. Currently, most agencies have limited information on the cost-effectiveness (CE) and long-term performance of PM strategies, so it is difficult to determine when and where these treatments should be used. The use of PM treatments based on a CE calculation and analysis is examined, and a decision tree (including treatments and strategies) is developed for each functional pavement class of the Ontario road network. Pavement data from the Ministry of Transportation of Ontario are used to perform a CE calculation for each suggested PM treatment and strategy. On the basis of a comparison and analysis of CE calculation results, guidance is provided on the right treatment, time, and strategy cost level for each functional pavement PM program within the Ontario environment. The results are summarized in the form of a decision tree.
Joint Sealant and Structural Performance at the Ohio Route 50 Test Pavement
Authors: Ioannides Anastasios M. , Long Allen R. , Minkarah Issam A.
Published: April 2007

The performance of joint sealants and the structural condition of the pavement at the Ohio Route 50 test site after 3 years in service are reported. The project involved 10 different sealant compounds (4 silicone, 2 hot-applied, and 4 compression seals) and 4 unsealed sections. A total of 15 different sealant-joint configuration combinations are examined. Compression seals generally outperformed the other sealants, and sealants in the westbound lanes were more effective than those in the east-bound lanes. These observations suggest that crew experience in sealant installation is a critical factor. Nonetheless, structural performance and surface profile smoothness appeared to be unrelated to sealant condition. Many of the sealant sections with high effectiveness values also exhibited high percentages of structural distresses and decreases in pavement surface smoothness. Flooding after intense rainfall may have softened the subgrade and caused transverse cracking and corner breaks. Implementing a drainage outlet maintenance program that includes cleaning silt and debris from the outlets annually is recommended. Unraveling the complex interactions of all these factors calls for long-term monitoring of both sealant and structural performance.