Control of vehicle speed is a central tenet of the safe systems approach to road safety. Most research shows that raising speed limits results in more injuries. Advocates of higher speed limits argue that this conclusion is based on older research, that traffic fatalities are decreasing despite higher speed limits, and that modern vehicles are able to safely travel at higher speeds. These arguments were used to justify raising speed limits on rural highways in British Columbia, Canada (July 2014). We used an interrupted time series approach to evaluate the impact of these speed limit increases on fatal crashes, auto-insurance claims, and ambulance dispatches for road trauma. Events were mapped to affected road segments (with increased speed limits) and to nearby road segments (within 5 km of an affected segment). Separate linear regression models were fitted for each outcome and road segment group. Models included gasoline sales to account for changes in vehicle travel. Our main findings were significant increases in (i) total insurance claims (43.0%; 95% Confidence Interval [CI] = 16.0–76.4%), (ii) injury claims (30.0%; 95% CI = 9.5–54.2%), and (iii) fatal crashes (118.0; 95% CI = 10.9–225.1%) on affected road segments. Nearby segments had a 25.7% increase in insurance claims (95% CI = 16.1–36.1%).
An experiment on rider stability while mounting: Comparing middle-aged and elderly cyclists on pedelecs and conventional...Published: 01 August 2017 by Elsevier BV in Accident Analysis & Prevention
Pedelecs, popular among elderly cyclists, are associated with a higher injury risk than conventional bicycles. About 17% of these injuries are due to falls while (dis)mounting. Using instrumented bicycles, this study aimed to identify factors contributing to the stability of self-chosen mounting methods in four user groups: 30-45 versus 65+ years of age and males versus females. Mounting stability on pedelecs was compared with that on conventional bicycles, in controlled experimental setting (task in a fenced off parking lot) but also in real traffic conditions (traffic light turns green). Two mounting phases were differentiated: phase 1 as the transition from 'earth bound' to 'balance' and phase 2 as the acceleration to achieve harmonized cycling. Stability was operationalised in terms of the duration of these phases: the shorter their duration, the higher the stability. Pedelecs were shown to be less stable in phase 1 than conventional bicycles, irrespective of user group. For all user groups, only in phase 2 the advantages of electrical support kicked in. Results obtained in traffic conditions confirmed the patterns obtained in the controlled setting, with as only difference a lower speed in traffic conditions, which held for both mounting phases and bicycle types. Also measures of physical limitations due to low muscle strength were shown only to be compensated for by pedal support in phase 2 and not in phase 1. Further, mounting characteristics affected pedelec stability in phase 1 and not in phase 2. Higher stability was associated with a) starting while seated and b) using the pedal to push off. Although, these mounting characteristics were confounded with age, gender, and muscle strength, the pattern of results still suggest certain mounting techniques to be more beneficial for pedelecs. The results further illustrate the importance of a deeper understanding of the interactions of bicycle types and user groups on critical manoeuvres and their potential contribution to the optimisation of pedelec design and the training of safe mounting techniques.
Road crashes have become a leading cause of injury and death and a major source of greenhouse gas emissions. Modes of active transportation (AT) such as walking and cycling are often overlooked in the community planning process. The Fused Grid (FG) is an innovative subdivision layout, developed by the Canadian Mortgage and Housing Corporation with the objective of balancing the needs of safety and health for residents, with those of the automobile and AT, all in pursuit of enhanced community sustainability. This study assesses the effectiveness of the FG model via an application of two recently developed assessment tools: the Canadian Healthy Development Index (HDI), and the Dutch Sustainable Transport Safety (STS) principles (collectively known as i-THRIVE in a new on-line tool). It was found that the FG is a successful model for building sustainably safe and healthy communities as it easily met the criteria of both the HDI and STS Principles. However, while the FG model can be applied relatively easily to a new community, retrofitting existing neighbourhoods can be challenging and is the subject of further research.
An empirical tool to evaluate the safety of cyclists: Community based, macro-level collision prediction models using neg...Published: 01 December 2013 by Elsevier BV in Accident Analysis & Prevention
Today, North American governments are more willing to consider compact neighborhoods with increased use of sustainable transportation modes. Bicycling, one of the most effective modes for short trips with distances less than 5km is being encouraged. However, as vulnerable road users (VRUs), cyclists are more likely to be injured when involved in collisions. In order to create a safe road environment for them, evaluating cyclists' road safety at a macro level in a proactive way is necessary. In this paper, different generalized linear regression methods for collision prediction model (CPM) development are reviewed and previous studies on micro-level and macro-level bicycle-related CPMs are summarized. On the basis of insights gained in the exploration stage, this paper also reports on efforts to develop negative binomial models for bicycle-auto collisions at a community-based, macro-level. Data came from the Central Okanagan Regional District (CORD), of British Columbia, Canada. The model results revealed two types of statistical associations between collisions and each explanatory variable: (1) An increase in bicycle-auto collisions is associated with an increase in total lane kilometers (TLKM), bicycle lane kilometers (BLKM), bus stops (BS), traffic signals (SIG), intersection density (INTD), and arterial-local intersection percentage (IALP). (2) A decrease in bicycle collisions was found to be associated with an increase in the number of drive commuters (DRIVE), and in the percentage of drive commuters (DRP). These results support our hypothesis that in North America, with its current low levels of bicycle use (<4%), we can initially expect to see an increase in bicycle collisions as cycle mode share increases. However, as bicycle mode share increases beyond some unknown 'critical' level, our hypothesis also predicts a net safety improvement. To test this hypothesis and to further explore the statistical relationships between bicycle mode split and overall road safety, future research needs to pursue further development and application of community-based, macro-level CPMs.
Comparing the road safety of neighbourhood development patterns: traditional versus sustainable communitiesPublished: 01 January 2013 by Canadian Science Publishing in Canadian Journal of Civil Engineering
The Canada Mortgage and Housing Corporation (CMHC) has been researching a sustainable community development pattern — the Fused Grid road network. This paper reports on research to compare the road safety level of the Fused Grid with four other networks, including: traditional (1) grid and (2) culs-de-sac patterns, and, recently developed (3) 3-way offset and (4) Dutch sustainable road safety (SRS) patterns. Community-based, macro-level collision prediction models were developed and applied with data from Vancouver, Ottawa, and Victoria. The research used standard experimental design methods, including: control–trigger variables, sensitivity analysis, and cross-sectional analysis. Statistically significant results were obtained, and suggested that neighbourhoods built following CMHC's Fused Grid road network pattern would realize a 30 to 60% higher level of road safety than the commonly-used grid and culs-de-sac patterns, and a level of safety comparable to the 3-way offset pattern. Further research topics were recommended. The Canada Mortgage and Housing Corporation (CMHC) has been researching a sustainable community development pattern — the Fused Grid road network. This paper reports on research to compare the road safety level of the Fused Grid with four other networks, including: traditional (1) grid and (2) culs-de-sac patterns, and, recently developed (3) 3-way offset and (4) Dutch sustainable road safety (SRS) patterns. Community-based, macro-level collision prediction models were developed and applied with data from Vancouver, Ottawa, and Victoria. The research used standard experimental design methods, including: control–trigger variables, sensitivity analysis, and cross-sectional analysis. Statistically significant results were obtained, and suggested that neighbourhoods built following CMHC's Fused Grid road network pattern would realize a 30 to 60% higher level of road safety than the commonly-used grid and culs-de-sac patterns, and a level of safety comparable to the 3-way offset pattern. Further research topics were recommended.
The growing automobile transport results in severe traffic congestion, pollution and road safety problems. Bicycling, as one of sustainable transportation mode, is encouraged in most developed countries for its attributes of convenience, low cost, non-fuel use, and zero-emissions. It is generally accepted that increasing bicycle use could improve road safety. Based on a comprehensive literature review, this paper discusses potential factors influencing bicycle use and bicycle collisions. Understanding these bicycle-related factors is useful to develop new bicycle-related Collision Prediction Models (CPMs) with generalized linear regression. These CPMs can support economic justification of much-needed major bicycle infrastructure investments, and also help policy makers to promote bicycling in an effective and economic manner. Also, a brief methodology of developing such macro-level CPMs is suggested. Based on a case study of City of Kelowna, BC, Canada, several new macro-level CPMs are proposed. Results reveal that the increase of bicycle use can lead to a decrease in total collisions despite an increase in bicycle collisions, which is consistent with the actual case. Also, the bicyclerelated exposure variable, bicycle lane length, has a significantly positive relationship with dependent variables: total collision frequency. In this case, it is concluded that increasing bike lanes (on-street and off-street) can be a good measure to improve road safety. Still, aimed on the research gap, this paper identifies potential works of high interests in future.
The building industry accounts for up to 40% of the earth’s energy usage from material extraction through building operation; housing constitutes roughly 30% of energy use in North America. Owners and consumers are looking for more efficient building systems that would decrease this use of energy. The material chosen to construct the structure of a building has the potential to reduce the building’s initial environmental impact and its life cycle energy use. However, this is rarely considered during conceptual design. Sustainable construction materials that have low embodied energy include earthen construction and straw bale construction. However, these materials are not widely accepted alternatives in North America because they are included only in select building codes in North America and around the world. In this paper, an extensive review of the current construction practice of sustainable construction materials is summarized. Durability concerns and limitations of the methods of construction are discussed, and areas of future research are identified.
Transferability of Community-Based Collision Prediction Models for Use in Road Safety Planning ApplicationsPublished: 01 October 2010 by American Society of Civil Engineers (ASCE) in Journal of Transportation Engineering
Collision prediction models (CPMs) are statistically developed mathematical models that relate the occurrence of traffic collisions to various traits or explanatory variables of locations and zones. This paper describes the use of several recently developed community-based, macro-level CPMs and model-use guidelines in a CPM transferability case study for spatial and temporal transferability. The objective was to test the model-use guidelines in an application that involved transferring CPMs developed using 1996 data for the Greater Vancouver Regional District (GVRD) for use in the Central Okanagan Regional District (CORD) using 2003 data. The GVRD and CORD are regions located 400 km apart in the Province of British Columbia, Canada. The case study was carried out in two parts. First, CPMs were developed using 2003 data for the City of Kelowna following recommended community-based, macrolevel collision prediction model development guidelines. Second, existing CPMs were transferred from the GVRD to the CORD, using the recommended transferability guidelines. An analysis of the results revealed that macrolevel CPM transferability was possible and no more complicated than microlevel CPM transferability. To facilitate the development of reliable community-based macrolevel collision prediction models, it is recommended that CPMs be transferred rather than developed whenever and wherever communities lack sufficient data of adequate quality.
This paper describes the application of previously developed community-based, macrolevel collision prediction models (CPMs) to evaluate the road safety of a regional transportation plan. The research objective was to present and test model-use guidelines in a regional road safety planning application. The data was extracted from over 400 Greater Vancouver neighborhoods in British Columbia, Canada, including output from the regional transportation model. The CPMs predicted a lower mean collision frequency region-wide due to a proposed three-year transportation plan, versus a do-nothing scenario. Recommendations have been made for future use of the CPMs in regional road safety planning applications. The application of macrolevel CPMs to this regional case study proved a solid step in the development of new and improved empirical tools for planners and engineers to include road safety in the planning process. It is hoped that these models and model-use guidelines will facilitate improved decisions by community planners and engineers, and ultimately, facilitate improved neighborhood traffic safety for residents and other road users.