Executive Summary. In December of 2001, the Region of Durham retained Synectics Transportation Consultants Inc. (Synectics) to prepare a report to:

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1 Guide Rail, End Treatment and Energy Attenuator Selection Guidelines Page 1 Executive Summary About one-third of all fatal crashes in North America each year involve a single vehicle. For crashes in rural areas, the proportion is even higher. In practically every single-vehicle collision resulting in a fatality, the vehicle left the roadway, and either overturned or collided with a fixed object. Road safety may only be measured in relative terms. There is no such thing as a roadway, open to traffic, that is completely safe. Mobility, by its nature, involves an element of risk. Minimizing the mobility risk by making the roadway (and the roadside) as safe as is possible, within the constraints prevailing, is a fundamental responsibility of public road authorities. In December of 2001, the Region of Durham retained Synectics Transportation Consultants Inc. (Synectics) to prepare a report to: Encourage the consideration of alternatives to guide rail, including hazard removal, crashworthy design elements, landscaping, and positive guidance solutions in the design and rehabilitation of Regional Roads; Research and report on the current state-of-the-art and emerging trends in the protection of road users from hazards via hazard shielding (with guide rail, guide rail end treatments and energy attenuators); Identify the full range of economic (quantitative) and performance (qualitative) criteria upon which alternative treatments may be judged, on a life-cycle, benefit-cost basis; Provide a comparative analysis of the options available, relative to the criteria developed above; Develop a decision-making aide for use by Regional designers and others in making optimal design/retrofit decisions regarding guide rail, guide rail terminals and energy attenuators; and Provide recommendations regarding the standardization of the Region s guide rail, guide rail terminal and energy attenuator devices, to streamline the maintenance management of these systems. The approach proposed by Synectics was to: 1. Conduct a brief literature scan on the current state-of-the-art in addressing roadside hazards (alternatives to shielding) and emerging trends in the protection of road users from hazards via hazard shielding (with guide rail, guide rail end treatments and energy attenuators); 2. Review the Region s current design guidelines for guide rail terminals and energy attenuators; 3. Briefly examine the range and diversity of devices currently in-service on Regional roads; 4. Conduct a best-practices survey of a limited number of North American jurisdictions acknowledged to be leaders in this area;

2 Guide Rail, End Treatment and Energy Attenuator Selection Guidelines Page 2 5. Confirm our understanding of the Regions planning, design, construction, operations, maintenance and rehabilitation/retrofit objectives with respect to establishing and maintaining a guide rail/end treatment/ energy attenuators policy; 6. Develop a comparison matrix that addresses typical applications for guide rail, guide rail terminals and energy attenuators; 7. Apply criteria, weighted according to Regional priorities, to establish an optimal solution in each case; 8. Develop similar criteria and a supporting process for the assessment of design alternatives in atypical applications; and 9. Provide findings, conclusions and recommendations on the future standardization of guide rail end treatments and energy attenuators on Regional roads. Findings The review found that Region of Durham is well-positioned to address issues relating to roadside safety and roadside protection. First and foremost, the Region recognizes the importance of roadside design, and the role of roadside protection devices in the provision of a safe roadway environment. The Region is actively implementing a programme of continuous improvement in the design, operation and maintenance of roadsides and roadside protection devices. This recognition, acknowledgement, and level of effort, are uncommonly foresighted amongst Ontario municipalities, and are to be commended. Second, the Region has conducted an inventory of their roadside protection devices, with the aim of addressing unmet needs for roadside protection, design deficiencies, devices no longer considered standard, and ongoing and future maintenance issues. With this information, the Region is in a position to show due diligence in providing a safe roadside environment, to set defensible priorities, and to allocate its available resources aimed at roadside safety improvement in a cost-efficient manner. Third, the level of appreciation amongst Regional staff of the importance of roadside safety issues, and their understanding of the principles under which the practice of roadside safety should be conducted, is very high. Regional staff has acknowledged the need to review its design, operations and maintenance practices to ensure that roadside safety is explicitly addressed as an integrated element of each process to the greatest degree possible. Fully integrating and harmonizing roadside safety considerations, and the specific needs of roadside protection devices, into design, operations and maintenance practices is seen as a priority by Regional staff. Future efforts, driven by their high level of motivation in this regard, will undoubtedly yield dividends in roadside safety improvement and reductions in the severity of run-off-the-road-type collisions occurring on Regional Roads. Finally, the Region has commissioned this assignment, to bring clarity to the range and diversity of roadside protection solutions currently available, and to recommend policies aimed at streamlining the selection, implementation and maintenance of roadside protection devices on Regional Roads.

3 Guide Rail, End Treatment and Energy Attenuator Selection Guidelines Page 3 The roadside safety device market offers a wide range of design solutions, suited to practically every roadside protection need. Many of the proprietary devices, proven effective in crash tests and offering desirable features, are available only at substantial cost. Others, while imminently suited to a specific purpose, are both narrowly applicable and extremely expensive. In routine applications existing, non-proprietary devices (e.g. Extruder, Eccentric Loader and Connecticut Impact Attenuator System CIAS) are cost-effective and offer an acceptable level of protection. Where site-specific circumstances require the use of a proprietary device, or mandate extraordinary performance (compactness, quick and easy post-crash restoration, self-restoring elements, environmental sensitivity, etc.), then the use of a suitable, proprietary device may be justified by a business-case built around a comprehensive cost/benefit analysis. The Regional road network is diverse, ranging from urban, low-speed arterial roadways to rural, highspeed facilities indistinguishable from the King s Highway in form, function and usage. This diversity presents a number of challenges for Regional staff responsible for roadside safety and roadside protection issues. Issues pertaining to utility and luminaire pole placement were noted in both low-speed and high-speed environments. Opportunities to set poles back as far as possible from the roadway were not always capitalized upon, and pole placement within the invert of ditches was noted as likely to channel errant vehicles into collision with them. In urban areas, with posted speed limits of 60 km/h or less (design speed of 70 km/h or less), barrier curb and gutter and a minimum 0.5 metre clear zone are often sufficient to meet roadside safety requirements. Field reviews conducted under this assignment noted a number of over-designed applications of roadside protection in low-speed areas that were more suited to high-speed facilities. While the shielding of fixed object hazards (e.g. bridge abutments) and terrain features (e.g. critical slopes) beyond the clear zone may be justified, often the treatment of these hazards and the termination of the barrier system can be achieved in a more simplistic manner, while ensuring cost-effective protection for the public. Where treatments better suited to high-speed applications have been employed in low-speed environments, cost-effective options exist to salvage the devices, and re-deploy them as part of a networkwide remediation programme. Redeployment may assist in reducing the overall resource requirement to achieve the Region s roadside protection goals. In rural areas, length-of-need to adequately shield roadside hazards, unconnected transitions between approach guide rail and bridge parapet walls, and three-cable guide rail to steel beam transitions, were noted as issues. Fill and drainage design requirements were cited as issues in the installation of Eccentric Loader end treatments. The presence of barrier curb and gutter in front of various barrier systems and end treatments is known to compromise performance, and was noted at numerous locations. Some drainage elements, shielded by guide rail, were noted to be susceptible to treatment by other means (e.g. cut inlet parallel to slope and install grate to make traversable), thus eliminating the need for guide rail. The requirement for traversable (3:1 or flatter) slopes behind cable guide rail, along with its maintenance challenges and performance in crashes involving the current generation of motor vehicles were noted as possible justification for discontinuing the use of this 1960 s era standard.

4 Guide Rail, End Treatment and Energy Attenuator Selection Guidelines Page 4 Operational, maintenance and performance concerns regarding box beam barrier are seen as justification for discontinuing its use, as well. Conclusions From this information, the following was concluded: 1. The Region should review its design processes to further enhance the integration of roadside safety needs and roadside protection device requirements. 2. The Region should continue its efforts to identify and address unprotected roadside hazards, and to upgrade existing roadside protection installations either through mitigation of the hazard by other means and guide rail removal, or through retrofitting to meet existing standards and practice requirements. 3. The Region should establish a prioritization plan for the mitigation of hazards that are either unprotected or that can be addressed by means other than guide rail, and for the retrofitting of guide rail systems, end treatments, transitions and crash cushions that are no longer meet standards. 4. The Region should, on the basis of this report, establish an approved devices policy, and a business case model for the justification of devices other than those on the approved list. 5. Three-cable guide rail should be phased out on all but low-volume roads. 6. Box beam barrier should be phased out entirely. Recommendations Recommendations regarding the selection and application of roadside barriers are as follows: 1. On the basis of life-cycle costs and performance, the Region should discontinue the use of threecable guide rail in all but low-volume road applications. Existing installations should be addressed under a retrofitting and upgrading programme. 2. On the basis of life-cycle costs and performance, the Region should discontinue the use of box beam guide rail entirely. 3. Box beam guide rail is known to be prone to corrosion of the splice plates and connecting bolts. In the interim, the Region should conduct an examination of its existing box beam guide rail installations, to ensure that all elements of those systems remain serviceable. Recommendations regarding the selection and application of end treatments are as follows: 1. The Region should standardize its routine steel beam guide rail end treatment requirements around the Eccentric Loader and Extruder for undivided roadway applications, and around the CAT for gore area and median applications.

5 Guide Rail, End Treatment and Energy Attenuator Selection Guidelines Page 5 2. The Region should standardize its routine concrete safety shape end treatment requirements around, in decreasing order of preference, the following devices: a) Transition to steel beam and use a steel beam end treatment; b) CAT (where space requirements or median applications, preclude (a)); c) QUADTREND (where space requirements preclude (a) and (b)); or d) QUADGUARD (in median and gore area applications, which preclude (c), and where space requirements preclude (a) and (b)). 3. Other devices should only be considered in exceptional circumstances, on the basis of the criteria outlined in this report, and be justified on the basis of a benefit/cost analysis. Recommendations regarding the selection and application of energy attenuators are as follows: 1. The Region should standardize its routine energy attenuator requirements around the CAT and/or the CIAS for gore area and median applications where there is limited collision experience. 2. Where space constraints, frequency of impact, and maintenance considerations may justify the use of a more sophisticated system (e.g. QUADGUARD, TREND, HI-DRO, HI-DRI, etc.), selection should be assessed on the basis of the criteria outlined in this report, and be justified on the basis of a benefit/cost analysis. Other recommendations, developed in the course of this study, are outlined below: 1. The separate conduct of guide rail and drainage design leads to conflicts between these design elements, and compromises the effectiveness of roadside safety treatments (e.g. barrier curb and gutter in front of guide rail system, insufficient fill to support and provide run-out behind Eccentric Loader end treatments). The Region should strive to better integrate roadside protection and drainage design during the design process. 2. The Region should develop an approved devices policy as a guide for designers. The policy should advocate standardization and uniformity in the selection of devices for routine applications, but should not preclude the specification of appropriate, special-circumstance devices where justified. 3. The Region should articulate and implement a roadside safety policy, and undertake a prioritized programme of roadside safety improvements. The programme should be aimed at addressing existing, unprotected hazards, and at retrofitting and upgrading existing roadside protection devices to address deficiencies.