Alberta Transportation Research Articles

Comparison of Rating Systems for Alberta Rock Slopes, and Assessment of Applicability for Geotechnical Asset Management

In 1999, Alberta Transportation and Economic Corridors (TEC) implemented the Geohazard Risk Management Program (GRMP) to identify, assess, monitor, and prioritize the mitigation of risk resulting from geohazard events at specific sites along the provincial highway network. The GRMP was developed to address a variety of geohazard types including rockfall hazards that occur at natural and constructed (cut) highway backslopes. An evaluation of various methods for the condition assessment of rockfall geohazards, including TEC’s current GRMP risk rating system, has been completed with the intent of better understanding the suitability of each method as TEC transitions to a formalized GAM program. The GRMP risk rating values for selected rockfall geohazard sites along highway corridors in Alberta were compared to values developed from the results of five established rock mass and rock slope rating systems. The results of this study demonstrate that TEC’s current GRMP risk rating system is a viable tool for the condition assessment and performance monitoring of rockfall geohazards, which could be utilized within a formalized GAM program, further benefitting from years of recorded application in Alberta. Of the other rating systems tested, the rockfall hazard rating system (RHRS) showed a strong correlation with the GRMP risk rating while Q-Slope, the Geological Strength Index (GSI) and Rock Mass Rating (RMR) correlation were marginal but displayed a potential for use as condition assessment tools. The work presented in this paper provides the first evaluation of rock slope rating systems for rockfall hazards along corridors in Alberta, directly comparing them to the slope performance as observed by TEC in a quantitative manner.

Blame attribution analysis of police motor vehicle collision reports involving child bicyclists

BackgroundInjuries resulting from collisions between a bicyclist and driver are preventable and have high economic, personal and societal costs. Studying the language choices used by police officers to describe factors...

Road mitigation structures reduce the number of reported wildlife‐vehicle collisions in the Bow Valley, Alberta, Canada

AbstractHuman population and economic growth have resulted in roads transecting much of the North American landscape and this has negatively affected wildlife populations by fragmenting habitat, impeding movement between populations and increasing the chance of wildlife‐vehicle collisions. A common conservation tool to counteract these effects is the incorporation of road mitigation structures (RMS, i.e., jumpouts and overpasses/underpasses/fencing) into highway systems. However, gaps remain in our knowledge on RMS efficacy due to a lack of long‐term multispecies studies that can assess temporal and species‐specific variation in use. We investigate the efficacy of the Alberta Environment and Parks and Alberta Transportation RMS on the Trans‐Canada Highway (TCH) in the Bow Valley by analyzing annual reported wildlife‐vehicle collisions over a 23‐year period and wildlife use of the underpasses over a ten‐year period. We found that the incorporation of multiple underpasses and jumpouts, along with fencing, reduced the number of reported wildlife‐vehicle collisions on the TCH. We also found that wildlife use of the RMS exhibited variation with regards to month and location. Overall, our results add to the research supporting RMS effectiveness and suggest that incorporating additional similar infrastructure has the potential to further reduce wildlife‐vehicle collisions on the TCH.

Adaptation of a Canadian culpability scoring tool to Alberta police traffic collision report data

Objective: The objective of this study was to adapt a previously validated Canadian Culpability Scoring Tool (CCST) to Alberta police report data.Methods: Police traffic collision reports from motor vehicle (MV) collisions in Calgary and Edmonton (Alberta, Canada) from 2010 to 2014 were used. Adaptation of the CCST was completed with input from personnel within Alberta Transportation, contributing to face and content validity. Two research assistants, given only the information necessary for scoring, evaluated 175 randomly selected MV–MV collisions. Interrater agreement was estimated using kappa (k) and reported with 95% confidence intervals (CIs). Discussion of disagreements between the research assistants and consultation from Alberta Transportation informed the algorithm used in the Alberta Motor Vehicle Collision Culpability Tool (AMVCCT). The AMVCCT was automated and applied to all motorists involved in collisions. Binary logistic regression was used to examine characteristics of the culpable and nonculpable drivers and their effects were reported using odds ratios (ORs) with 95% CIs.Results: Interrater agreement for the random sample was excellent (k = 0.95; 95% CI, 0.92–0.99). Of those drivers hospitalized, 1,130 (37.54%) were rated not culpable and 1,880 (62.46%) were rated culpable. The odds of being culpable were higher for males than for females (OR = 1.43; 95% CI, 1.23–1.66). The odds of being culpable were higher in those impaired by alcohol than those considered “apparently normal” (OR = 61.10; 95% CI, 22.66–164.75). The odds of being deemed culpable, when compared with drivers >54 years old, were higher for those <25 years old (OR = 1.72; 95% CI, 1.35–2.20) and lower for those in the 40- to 54-year-old age group (OR = 0.78; 95% CI, 0.63–0.96). Driving between 12 a.m. and 6 a.m. resulted in higher odds of being culpable compare with all other 6-h time blocks. Direction and statistical significance remained consistent when applying the tool to all MV collisions. Sensitivity analysis including the removal of single vehicle collisions did not affect the direction or statistical significance of the main results.Conclusions: The AMVCCT identified a culpable group that exhibited characteristics expected in drivers who are at fault in collisions. The age groups 25–39 and 40–54 demonstrated different results than the CCST. However, this is the only difference that exists in the findings of the AMVCCT compared to the CCST and could exist due to differences between the driving populations in Alberta and British Columbia. It is possible to adapt the CCST to provinces outside British Columbia and, in doing so, we can identify risk factors for collision contribution and not-at-fault drivers who represent the driving population.

Road users’ perception of roughness and the corresponding IRI threshold values

One of the primary objectives of highway agencies in Canada is providing a safe and reliable road network with a good level of service. In the Province of Alberta specific International Roughness Index (IRI) threshold values classify pavements into good, fair, and poor condition categories to manage and schedule rehabilitation and maintenance programs. This research investigated the significant factors that affect the perception of road roughness and established IRI threshold values for good, fair, and poor road condition based on public perception. A questionnaire was designed to investigate the road users’ perception and included questions covering gender, age, familiarity with the road, type and model of car, and perception of road roughness. In addition, psychometric scaling analysis was used to develop a set of IRI threshold values for classifying road condition based on public perception in the Province of Alberta. According to the results of the survey, Alberta Transportation threshold values of IRI do not agree with the road users’ opinion and an alternate set of threshold values was developed. The analysis of the survey results identified that trip purpose, driving experience, dry surface, and familiarity with the road are the most significant factors that influence the perception of road roughness.

Traffic inputs for mechanistic-empirical pavement design guide using weigh-in-motion systems in Alberta

Mechanistic-empirical pavement design guide (MEPDG) uses axle load spectra and the number of axle applications to characterise traffic loads for pavement design. Alberta Transportation installed weigh-in-motion (WIM) systems at six highway locations to characterise traffic loads in Alberta for MEPDG design. Seasonal and regional trends in traffic characteristics of the six WIM sites were investigated and compared with the default values in the MEPDG for the years 2009 and 2010. Truck traffic classification (TTC) and axle load distribution factor (ALDF) for the WIM sites showed deviations from the MEPDG defaults. Seasonal variations were also evident in the distribution of different classes of truck throughout the year. Differences are attributed to cold climate conditions and special truck traffic in Alberta because of local industries. Influence of the differences between site-specific traffic characteristics and the MEPDG defaults on the performance of both flexible and rigid pavements for Alberta conditions was investigated through a sensitivity analysis. It was found that the flexible pavement performance is sensitive to TTC and ALDF, and the rigid pavement performance is most sensitive to ALDF.

A Comparative Study between the Alberta Transportation Flexible Pavement Design and the MEPDG

The main objective of this study was to compare the flexible pavement design using the Alberta Transportation Pavement Design (ATPD) procedure to the recently developed Mechanistic Empirical Pavement Design Guide (MEPDG). Findings from this study explore the possibility of MEPDG implementation for pavement design in Alberta, Canada. Six different design cases were defined with three different traffic levels and two different subgrade materials. Each case was designed following the ATPD procedure. The ATPD design thicknesses were then used in the MEPDG for each case to predict the pavement performance reliabilities at the end of the 20-year design life. The design for each case was repeated 27 times, using the climatic files available in the MEPDG for Alberta. It was found that, when using the MEPDG, only the cases with a strong subgrade material and a low level of traffic meet the default limit value for total pavement rutting. Also, all sections designed following the ATPD procedure, when designed using the MEPDG, fail due to excessive International Roughness Index (IRI).

Network-Level Performance Measures for Low-Volume Highways in Alberta, Canada

The province of Alberta is responsible for 30,740 km of highway, of which 4,320 km is gravel surfaced. Approximately 8,750 km (28.5%) carries traffic volumes of fewer than 400 vehicles per day. The objectives of this study are to outline network-level performance measures for highways in Alberta and to ensure that they are effective for managing low-volume highways. The performance measures used relate primarily to physical condition and functional adequacy. In 2002 these measures were studied as part of a joint project with the University of Calgary in an attempt to make them more budget sensitive. Criteria were determined and subsequently adopted by Alberta Infrastructure and Transportation. Subsequent to that, a study was undertaken to determine optimal levels for these measures. These optimal measures would be used to set desired future performance targets. The results showed that on the order of 5% of the highways should remain in poor condition and should not be part of the backlog to be corrected. It was at first thought that the majority of these highways would be low-volume roads, but this did not prove to be true, primarily because of the younger age of these roads. The study also examines the cost-effectiveness of projects to pave low-volume gravel roads in comparison with other projects in the program. Cost-effectiveness is defined as agency cost per user per kilometer over a 20-year life-cycle. In conclusion, a future direction is suggested for the department to follow with respect to its low-volume highway improvements.

Performance assessment of FC girder bridges in Alberta

A large number of precast prestressed concrete multi-girder bridges were constructed in Alberta in the early 1960s. Major benefits of this type of construction included the elimination of the cast in place concrete bridge deck and the accelerated pace of construction in erecting the bridge. However, after providing 10 to 20 years of service, some of these bridges started to form longitudinal cracks in the deck directly over the girder joining shear key locations. Once a crack was formed in the shear keys, salt and water would penetrate the wearing surface and weaken the shear key grout. This brought about concerns regarding adequate load sharing among the girders and corrosion of the prestressing tendons within the girders. An extensive survey was undertaken to observe the longitudinal cracking on these bridge decks. The objectives of the field survey were to look for possible trends or relationships between various influencing parameters and the performance of these bridges. Field data were obtained from a visually selected sample survey and a comprehensive bridge record survey based on Alberta Transportation (Government of Alberta) bridge files. The parameters investigated for influence on bridge performance were span length, span width, bridge skew, service age, and traffic volume. Finally, the rehabilitation schemes used on these bridges in the past are described, and the strengths and weaknesses of each rehabilitation strategy are discussed.Key words: bridges, concrete bridges, bridge girders, load sharing, rehabilitation, shear keys, assessment, traffic loads, lateral prestressing, transverse stiffness.

Shear rehabilitation of G-girder bridges in Alberta using fibre reinforced polymer sheets

Many bridges were built in Alberta after World War II with type G-girder precast concrete elements. Today, there are approximately 1500 G-girder bridges still in service all over the province. These bridges are typical short span (approximately 6 m long), simply supported, and without shear keys between girders. Structural deficiency of the G-girders, especially in shear, plus the economic constraints of the government demand that an economical and efficient method for rehabilitation of these bridges be developed. A research program at the University of Alberta, in collaboration with Alberta Transportation and Utilities and ISIS Canada, has been established to study the feasibility of using fibre reinforced polymers (FRP) to rehabilitate concrete bridge girders deficient in shear. This paper will address the structural deficiency of the G-girders and present eight full-scale test results from four G-girders removed from existing bridges. Carbon and glass FRP sheets and two repair schemes were used in the rehabilitation. Three commonly used shear strength evaluation methods, strut-and-tie model, modified compression field theory, and grid analysis, are investigated. The loads predicted by these three methods are in good agreement with the experimental results. The shear contribution of the FRP sheets at any angle can be accurately accounted for in the analysis. All three methods are found to be consistent.Key words: analysis, beams, bridges, composite materials, design, fibre reinforced polymers, rehabilitation, reinforced concrete, shear strengthening.

Sample Size Analysis for Asphalt Pavement Quality Control

A review of the quality assurance practices of Alberta Transportation & Utilities was undertaken for each of three quality test measures: (1) Asphalt content; (2) percent compaction; and (3) aggreg...

Effect of Variability on End Product Specifications

In the past 10 years a number of transportation agencies have adopted end product specifications (EPS) as part of their quality assurance programs. The basic premise behind EPS is that the contractor is renumerated based on how well their final product meets specifications set by the transportation agency. For example, an EPS for asphalt concrete pavement might state that the field density should be within 97% of the Marshall density. If the field density is below this value, the contractor would receive a penalty, whereas if the field density is above this value the contractor would receive a bonus. Because of uncertainty regarding the exact relationship between the reduced (or increased) performance of the product and the measure of effectiveness, the price adjustments were established based on engineering judgment and were indirectly related to anticipated performance. For example, the transportation agencies pavement engineers would look at past performance in developing guidelines for what reasonably could be expected for a given EPS. However, the fact that many agencies collect and save EPS data means that the variability in the EPS may now be analyzed and the effects studied. This paper demonstrates how the data collected from an EPS, and in particular the variability measures identified from these data, may be used to identify optimal testing strategies and to identify the risk, to both the producer and the agency, inherent in the bonus/penalty schedules. In addition, the trade-off between sample size and testing accuracy will be demonstrated. Last, the implications of incorporating variance within the EPS will be explored. Data obtained from Alberta Transportation and Utilities on Marshall density and field density EPS measurements will be used to illustrate the methodology and demonstrate the key components of the paper.

Development of Bayesian Regression Model to Predict Hot-Mix Asphalt Concrete Overlay Roughness

Predictive equations are central to the many tools highway professionals use to design, maintain, and manage our highway infrastructure. However, adequate data bases to support the development and updating of these models are often lacking. These data bases are often inadequate in sample size, noisy, or incomplete. Conventional statistical modeling tools, such as classical regression analysis, meet with limited success in these applications. A promising solution lies in the use of Bayesian regression, which explicitly allows expert judgment, collected from in-house or external experts, to be used to supplement poor-quality data. An overview is presented of the development of a Bayesian predictive model to forecast the progression of roughness in hot-mix asphalt concrete overlays using data and expert judgment provided by Alberta Transportation and Utilities.

Development of Bayesian Regression Model to Predict Hot-Mix Asphalt Concrete Overlay Roughness

Predictive equations are central to the many tools highway professionals use to design, maintain, and manage our highway infrastructure. However, adequate data bases to support the development and updating of these models are often lacking. These data bases are often inadequate in sample size, noisy, or incomplete. Conventional statistical modeling tools, such as classical regression analysis, meet with limited success in these applications. A promising solution lies in the use of Bayesian regression, which explicitly allows expert judgment, collected from in-house or external experts, to be used to supplement poor-quality data. An overview is presented of the development of a Bayesian predictive model to forecast the progression of roughness in hot-mix asphalt concrete overlays using data and expert judgment provided by Alberta Transportation and Utilities.

Sequential models to determine intercity Commodity Transportation Demand

The objective of this study is to determine the demand for commodity transportation using the conventional sequential modelling approach. In this study, the amounts of productions and consumptions of commodities at various locations were obtained from a commodity flow survey (shipper and consignee type) conducted by Alberta Transportation, Edmonton, in 1977 and 1978. Optimized gravity model for distribution and Log-linear and Logit models for modal split were developed from the above survey data. These models are discussed in this paper. The above three stages of modelling process yield the demand for commodities between origins and destinations in the province of Alberta. Demands for commodities (flows) are represented graphically in the form of commodity flow diagrams (CFD) between the population centres (origins and destinations). They also show the demand for commodities between origins and destinations by different modes, truck and rail. The CFDs for a few selected centres are shown to indicate the pattern of commodity flows across the province. They indicate that truck transport dominates the movement of all commodities. The modelling procedures and the results shown in this paper are applicable for transportation planning.

Design and Construction of a Buried Precast Prestressed Concrete Arch

This paper describes the design, manufacture and construction of a buried precast, prestressed concrete arch, with a span length of 19.6 m (64.3 ft) and an overall length of 173 m (566 ft), which carries highway traffic over railway tracks near Obed in Alberta, Canada. In design, a nonlinear finite element analysis was undertaken to account for the interaction between the structure and surrounding soil, as the arch was subjected to backfill and highway loadings. This allowed the arch wall thicknesses to be reduced substantially when compared to the thicknesses used in conventional designs. The arch was erected over a Canadian National Rail main line without disturbing railway traffic. The structure was designed to provide Alberta Transportation and Utilities years of service, with maintenance costs lower than those normally associated with highway bridges.

Hydraulics of culvert fishways V: Alberta fish weirs and baffles

This paper presents the results of a laboratory study of the hydraulic performance of fish weirs and fish baffles used by Alberta Transportation for improving the fish-passing capacity of culverts. It was found that if the longitudinal spacing of the weirs is limited to 0.6 and 1.2 times the diameter of the culvert, their performance is comparable to that of the corresponding weir and slotted-weir baffle systems, with regard to the depth of pool between the baffles as well as the barrier velocity. On the other hand, the fish baffles did not perform as well as the fish weirs under the conditions tested. Key words: culverts, fishways, baffles, turbulent flow, hydraulics, open-channel flow.

Oil and Gas Developments in Western Canada in 1989

There were 5513 wells drilled in western Canada during 1989, 30% fewer than in 1988. Total meterage drilled was 6,459,797 m, for an average well depth of 1172 m. Exploratory drilling in 1989 dropped by 13% and development drilling by 40% from 1988 levels. British Columbia was the only area in western Canada with increased activity. The industry continued to acquire more acreage for less total bonus at provincial Crown sales throughout western Canada. During 1989, 3,564,827 ha were acquired for a total bonus of $484,872,000 (FOOTNOTE 5). Although the total disposition of Crown lands decreased only 4%, the average bonus dropped to $136/ha, down 26% from 1988. In Alberta, the most active exploration areas were the southern and eastern Mesozoic gas play, the western deep Devonian gas play, the oil plays on and adjacent to the Peace River arch, and the Middle Devonian carbonate oil plays in the northwest. In British Columbia, the most active exploration areas were the Mesozoic and Paleozoic gas plays in the northeastern portion of the province. For the first time in 5 years, Crown drilling rights were issued within the Fraser Valley in the southwest. There was a focus on gas exploration in the province as pipeline reversal was implemented, permitting access to Canadian and California markets through the Alberta transportation network. In Manitoba, exploration and development activity continued to decline. In northern Canada, exploratory drilling success, offering of Crown lands for exploration, approval of gas exports, and indications that many of the Native lands claims may be approaching settlement, all provided exploration encouragement for the next decade. Exploration activities occurred throughout the Northwest Territories from the offshore Beaufort to the southern border. In Saskatchewan, active exploration areas were shallow Mesozoic gas plays in the western portions of the province and deep Paleozoic oil plays in the south.

Modal Split Analysis Using Logit Models

This study attempts to identify the mode and the factors that contribute to the selection of a particular mode for commodity movements provincially based on average shipment size, control, loads, hire, and type of commodity. The main objective of this study is to propose a more comprehensive and statistically credible method to analyze the vast data required in transportation planning. It involves the application of standard statistical techniques such as the log‐linear and logit models. The data are collapsed to form multidimensional contingency tables in order to develop these models. The data from both shippers and consignees are taken from a survey conducted by Alberta Transportation, Canada. From the analysis it is found that truck and rail are the only two major carriers of freight across the province. Truck mode dominates over rail in transporting all commodities. The less‐than‐full‐load market belongs exclusively to truck mode. The rail mode shares a very small percentage (<15%) of the full‐load m...

Some implications of the new speed–volume curves to highway user cost and sizing of roads

This paper investigates some implications of the speed–volume relationships for two-lane rural highways as proposed in the new edition of the U.S. Highway Capacity Manual, which is expected to be completed soon. The effect of the new speed–volume curves on road user costs is analysed by considering the case of Alberta Transportation. The analysis carried out in this paper indicates that the new speed–volume curves, when employed with the traditional values of other variables, such as vehicle running costs and value of travel time, produce cost–volume relationships that might appear unacceptable from both the highway agencies' and the road users' perspective. To overcome such a limitation it is suggested that a cost of comfort and convenience should be computed and added to the user cost.Basing their proposal on a survey of Alberta households and the actual practice of road sizing by Alberta Transportation, the authors present a generalized mathematical model to estimate the cost of comfort and convenience. The structure of the model and its independent variables include the considerations of (a) the relative importance of driving comfort as perceived by road users, (b) the unsatisfied demand (overtaking demand minus actual overtaking) curve, (c) the type of road use, (d) volume-to-capacity ratio, (e) desired highway speed, and (f) vehicle classification. The paper discusses and demonstrates how this model can be calibrated and used for economic analysis for designing and upgrading of rural highways. Key words: transportation, highway economic analysis, road user costs, cost of comfort, speed–volume curves, highway design.