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Workshop on Synthesis of Improved Sets of Safety Measures © ARROWS Consortium Project Co-ordinator Prof. George Kanellaidis (NTUA). email: g-kanel@central.ntua.gr The present Deliverable 3 reports on the work carried out within ARROWS Workpackage 3 (Workshop on Synthesis of Improved Sets of Safety Measures). The report includes a detailed record of the two-day Workshop, held in Athens (GR) on the 24th and 25th November 1997 (ARROWS Milestone III) and attended by ARROWS consortium members, the responsible officer of the European Commission, and representatives from national administrations, contractors, Universities and research institutes from all across Europe. Deliverable 3 also includes a summary of the proposed improvements to the existing state of practice that arose from the Workshop. The Workshop consisted of the following sessions, presented in chronological order: Opening Session: Strategy and policy aspects of road work zone safety Session A: The designer's viewpoint: Road work zone safety measures, standards and practices Session B: The user's viewpoint: Behavioural and safety aspects of road work zones Session C: Effectiveness of road work zone safety measures Supplement to Session B: Presentation of initial results of the scenario construction process Session D: Implementation issues Closing Session: Towards the ARROWS Framework Each session included presentations by both ARROWS Consortium members and guest participants, followed by a round of discussion. The report is based on the audio recording of the Workshop, the presentation texts / outlines supplied by participants, and the notes taken by the sessions' rapporteurs and NTUA team members. Strategy and policy aspects of road work zone safety At the beginning of the Workshop, Prof. George Kanellaidis (NTUA - Project Coordinator) welcomed Workshop participants in Greece and made a brief introduction to the project concept and context and the achievements so far. It was emphasised that the Workshop - as an interactive process - was structured in such a manner as to incorporate the views of the eventual users and help reach maximum usability of the ARROWS Practical Handbook The first presentation, made by Mr Ioannis Dimitropoulos (NTUA), was a review of the progress of the project so far (including project targets, approach, and findings) and the remaining steps to be made in order to reach its objectives. A very brief presentation was made on the main targets of the ARROWS Project and on the project background, including the review of safety measures, standards and practices (first ARROWS Work Package). A reference was made to the tools used in ARROWS in order to ensure a fruitful output, including: definition of a common typology; the expertise of the project consortium; the Workshop - with the main objective to integrate all findings and to result in a synthesis of proposed improvements in practice and methodology; and compatibility of the final product with existing national frameworks and international agreements. The results and findings so far - integrated in the first and second ARROWS Deliverables - included: (a) established conclusions and strong evidence; (b) weak indications / missing knowledge; (c) state of the art in research methods and suggested improvements; and (d) recording and comparison of existing practices across Europe. The presentation was concluded with the structure of the Workshop, emphasizing the contribution of the Workshop to the next phases of the project - by maintaining contacts with Workshop participants and by summarizing conclusions and proposed improvements, being the basis for the principles, recommendations and the handbook. Mr Rene Bastiaans (European Commission - DG VII/E3) made a presentation on EU Road Safety Policy and RTD Activities on Road Work Zone Safety. Although there is no explicit European policy on safety at road work zones, it is warranted to carry out research to improve safety at roadworks. The Commission Road Safety Action Programmes target both the determinants of accidents as well as measures to reduce the consequences of accidents when they occur. The strategy comprises three activity lines: (1) gathering information, information dissemination and best practice; (2) accident avoidance measures; (3) tools to reduce the consequences of accidents. The ARROWS research project can be looked at from these different activity lines. Harmonisation of road work zone safety measures should in the first place improve safety for road users and workers. It is worthwhile to investigate if "self-explaining road workzones", aiming at appropriate driver/rider behaviour, can be designed and implemented across Europe. Bringing together best practice in a handbook can be a very effective way of harmonisation. Early end-user involvement in the handbook development process, and actively getting feedback from them, is not only instrumental but essential in arriving at ARROWS' central objective: a handbook for practical guidance to road network managers. Ms Maria Sakki (CEN/TC 226 and COST 331 representative for Greece) made a presentation on CEN/TC 226 and COST 331. The first part of the presentation dealt with the standardization work of the CEN Technical Committee TC 226 for the work zone safety devices. This work is being done on the basis of six essential requirements: (1) mechanical resistance and stability; (2) safety in case of fire; (3) hygiene, health and environment; (4) safety in use; (5) protection against noise; (6) energy economy and heat retention. Ten of the standards already prepared for road equipment are related to the road work zone safety devices and mainly refer to the: horizontal signalisation; cones and cylinders; temporary signal systems; warning and safety light devices (danger lamps); variable messages etc. The second part of the presentation was related to the research Programme Cost 331: "Requirements for road markings", whose basic purpose is to provide a scientific basis on which to harmonise the quality and design of road markings and thus to promote a uniformly high level of safety throughout the European road network. The application field of the Action is limited to interurban roads and would cover road markings (white and yellow) such as: long lines (continuous and broken); retroreflective studs; directional arrows; and chevrons. The designer's viewpoint: Road work zone safety measures, standards and practices An overview of the safety measures which have been inventorised in ARROWS Task 1.2 was presented by Mr Nicolas Poriotis (3M / Poriotis Consultants). The presentation included items used in road work zones to improve traffic safety and traffic flow characteristics. It is worthwhile to mention that within Task 1.2 the existing state-of-the-art in items used in road workzones have been presented without a mention of the specific way in which they should be used in each case (which was the object of subsequent tasks), i.e. Task 1.2 presented what exists but not how it should be used. Dr Wolfgang Schulte made a presentation on the review of standards and practices, which was the objective of ARROWS Task 1.3. A pan-European review revealed that, in the standards, directives, recommendations or similar sets of regulations applicable, attention is paid primarily to the designing of work zones on motorways, highways, and non-urban roads and - additionally - to work zones which are set up in a permanent manner or ones which are operated in an interrupted manner. Only a limited range of different measures for the securing of work zones are to be found mentioned in the different layouts; it seems that numerous recent products have not yet found their way into the guidelines. The example of motorway contraflow layout was presented as a candidate standardisation case: depending on the traffic volume, two alternative concepts for guidance can be used for the diverted flow, in both of which only few different signs are used, but on various positions and in different quantities. The review of implementation of work zone standards revealed that, in the more recent regulations, increasing attention is being paid to the safety of those working in the work zones; in addition, both safety and traffic-flow considerations are important in guidelines. Depending on the particular legal requirements, work zone plans (featuring signs, markings and safeguard systems) have to be prepared, checked, corrected - if necessary - and then applied by the responsible official authority. Mr John Boender (CROW) made a presentation on Harmonisation and Standardisation issues. He presented some items that could be proposed by ARROWS for European uniformity such as: colour of the traffic markings and traffic signs; devices and design elements for each work zone section; minimum sizes and quality indicators for the size; visibility and reflectance of the material of the traffic signs; minimum requirements for the use of protective barriers which will also serve traffic guidance. Ms Sophie Jehaes (CRR) made a presentation on the interoperability and harmonisation principles and explained how these principles - as important "thought tools" - can be used in the outputs of the project and particularly in the Practical Handbook. The interoperability principle can be linked to: layouts (allowing to reduce the number of different layouts in the handbook); and material (possibility of using a same type of material for as many different types of workzones as possible). Harmonisation is the first step of standardisation; in the ARROWS project this principle has been applied in the creation of a typology, giving a common basis and a work tool for realisation of the subsequent stages. Dr Manuel Romana (UPM) presented how work zone safety is dealt with in Spain. The good experience of ten years of relevant legislation shows the importance of bringing in all actors involved, as well as of the use of separate documents with procedures. These issues should be considered when dealing with the ARROWS Handbook. The importance of dissemination and the value of a flexible and simple Handbook were also emphasized. The issues raised during discussion concerned mainly the harmonisation proposal of ARROWS, in particular the role and context of the Practical Handbook. Concerning the safety measures to be included in the Practical Handbook, a further screening should be made of what has been written in Task 1.2, focusing on safety measures that are more important to road work zones. Innovative and new equipment has been inventorised: this is common in use but not found in national regulations. However, an ARROWS proposal, including new things and ideas, will have to face the fact that lengthy procedures are needed for changing standards. It was stressed that it is important to produce a Handbook flexible and not too rigid, to be applied by the different Member States but not to be limited to current technology. TERN motorway standards might be a good basis for harmonisation proposal of ARROWS. For example, one harmonisation issue is the colour of the background of the traffic signs. A major issue that was raised from the discussion is, given that many of the regulations have been based on "religion" more than on scientific results, how much "religion" should be injected to ARROWS proposal, since it is not acceptable to change regulations without research. Furthermore, CEN standards introduce a legislative aspect in addition to the previous question. On the other hand, ARROWS has to rely on "best common practice" and research. It was also agreed that, concerning the Handbook, ARROWS can give a proposal for harmonised signing and layouts. It is, however, more important to include general underlying principles - concerning, for example, implementation or procedures - than concrete and too detailed proposals of specific dimensions or layouts. It was also mentioned that increasing attention is being paid recently to the safety of pedestrians, as well as that research is being carried out looking for new technologies and methods aiming at a safer working environment for road workers. Finally, it was agreed that quality and reliability in signing is of great importance. The user's viewpoint: Behavioural and safety aspects of road work zones A significant portion of Session B was dedicated to the Accident Scenario Construction exercise, which is to be reported separately in Task Report 4.1. The presentations made prior to the exercise highlight behavioural and safety aspects, based on the reviews carried out within ARROWS Workpackage 2. Ms Lena Nilsson (VTI) presented the methodology and findings of Task 2.1 (behavioural studies). The information was obtained from reviewing available literature and analysing it by means of a classification "model". Certain limitations, such as inconsistent terminology, poorly described factors and conditions and relative lack of statistical testing, made it difficult to draw clear and generalizable conclusions. One consistent (and expected) finding was that drivers speed at roadworks (commonly 20 km/h above the limits, often by a lot more) and usually change (reduce) their speed abruptly. Speed-reducing devices are more effective when positioned prior to the transition area, although it is noted that mental overloading (through use of too many devices) may lead to accidents even when speeds are reduced. Standardization is usually assumed to contribute to safety, although concern is expressed for familiarity potentially leading to "false safety" and lack of alertness. Most behavioural studies were carried out in the United States; the direct transfer of proposed safety measures may not always be advisable. It is suggested that attitudinal surveys of road users as well as more investigations on non-motorway roads will be useful in the future. Little is specified about the type of road-to-work zone interaction in studies reviewed, with contraflow being most common. Additional evaluation problems were caused by (a) the lack of mentioning the specific safety measures used, or (b) the incremental placement / testing of safety devices. Finally, apart from speed and lateral position, few other behavioural variables were considered. Mr Chad Gundy (SWOV) made a presentation on road work zone accident studies, noting that the problems mentioned by Ms Nilsson were not unique for behavioural studies but also came up in accident-related reports: small sample sizes, ambiguous data and definitions, lack of good experimental controls, biased data collection, relative non-use of statistical methods (or use of them to test the wrong hypotheses). Some of the main findings from the analysis of reviewed studies are: (a) work zones are more dangerous than non-works sections, usually by a few tens of percent; (b) no hard conclusions can be derived on the relative risk of different work zone types or parts - apart from the finding that the run-off area is safer than the rest of the work-zone; (c) future studies could focus on testing the "augmented null hypothesis" (via measurement of the relative accident rate beforehand and of the exposure at the time of road works) and on performing innovative analyses such as pan-European studies, meta-studies or accident scenario construction. However, the findings from existing studies do not allow for a lot of hard conclusions useful for the handbook. Next, Mr Gundy proceeded with an introduction to the accident scenario construction exercise. The rationale for accident scenarios lies in the fact that not enough is known about accidents at work zones, thus expert "guessing" could be useful for constructing a shared image of these. Accident scenario construction consists of four phases: preparation; brainstorm / discussion (part of the Workshop); survey; and analysis. For the brainstorm, the Workshop participants would split into six working groups, each dealing with a separate question - and, time permitting, identifying relations between the factors identified. Brainstorm results would be summarized in the supplement to this Session. Effectiveness of road work zone safety measures The session started with an overview of research methods used and proposed for the evaluation of road work zone safety measures (ARROWS Task 2.3), presented by Mr Nicolas Poriotis (3M / Poriotis Consultants). The different possible perspectives of evaluation (e.g. effects of alternative designs; effects on different groups of people involved; contradicting goals in traffic, etc.) and the diversity and multitude of methods were noted. The main steps identified were: laboratory research; scale model testing; field testing; and road /real traffic conditions testing. Each step was described as to their purpose, domain of application and other characteristics, and a number of dependent variables commonly measured (speed, lateral / longitudinal position, acceleration / deceleration, etc.) were identified. Eventually, a basic set of experimental methods was proposed, consisting of: (a) office design, (b) simulation design for the more important work zones, (c) test track testing for innovative design or complicated work zones, (d) road testing for purposes of standardization. Mr Graham Coe (TRL) analysed two measures used in the U.K. for the purpose of reducing speed. One is the use of speed cameras, as an enforcement measure. Their use is not equally spread through the country, due to different attitudes of local police forces. Where used, there are commonly about six dummy units for each real camera. The measure has proven to be effective in reducing speeds, especially for lorries. The other method is the "convoy working technique", which is useful in areas where the width of the carriageway is not enough for provision of the required lateral buffer space. The method can be used with either one or several works vehicles, driven at a given low speed and thus physically forcing the traffic (following behind on single file) to travel at that same speed through the work zone. For the success of this measure, it is important to make it understood to drivers by careful use of signs / signals. In the last presentation for this session, Prof. Anthony Stathopoulos (NTUA) spoke about telematics applications for road work zones. Telematics is used as a tool with the main purpose of introducing observation of the traffic flow, not just the individual behaviour of each driver. In addition, time dependency can be introduced in the operation of work zones (e.g. for reassigning lanes to opposite directions in urban road work zones, depending on time of day). Information provision will be enhanced when the RDS traffic message channel project is materialized. Notions such as cooperative driving are expected to become part of future motorways, reducing the driving task requirements. Finally, telematics allows one to have a comprehensive control of the road environment and to test alternative scenarios concerning work zones. In the round of discussion that followed, the following main points were made:
SUPPLEMENT TO SESSION B: Presentation of initial results of the scenario construction process Mr Chad Gundy (SWOV) introduced the presentation of initial results of the six brainstorms that took place at the last part of session B. The group at Table 1 had to find a list of external factors that influence traffic exposure / accident rates. The group at Table 2 dealt with unsafe acts, defences and psychological precursors. The group at Table 3 dealt with latent failure types. Table 4 worked on actors, their goals, resources and strategies. Table 5 looked into risk factors, and Table 6 discussed accident types. Implementation Issues Session D dealt with implementation issues and covered the application in Central / Eastern European countries, the viewpoint of construction managers and the viewpoint of public road administrations. Regarding Central / East European Policy, the document "Proposal for Harmonisation of TEM Motorway Traffic Signing: Proposals for Temporary Signing" describes Central / East European policy and practice. In a presentation by Mr Pavel Tucka (CDV), the following were the main points:
On the contractors' role, a presentation was made by Mr Rene de Groene (Traffic Service van Strien BV). Mr de Groene gave an account of the history of safety measures and standards in the Netherlands. Referring to the current practice he mentioned that Dutch work zone policy aims at "zero accidents". The development of the national policy was based on the following principles: collective (by both authorities and contractors) development and implementation of lines of action; placing more responsibility on contractor for safety; increasing the level of control by the authority; introducing new systems for road works. Regarding the contractors' role, he noted that in the Netherlands the planning of safety measures is entirely assigned to special contractors, whose role is: to formulate the specifications (for each application) in consultation with the principles and the other parties involved; to decide on the safety measures required for the particular application (preparation of drawings/plans, description of work); to realise the safety measures (in the field) and to check up during the execution; to provide employees with the necessary training; and to rent the safety equipment. Regarding the administrators' viewpoint, presentations were made by Mr Jan Boone (Rijkswaterstaat) and Mr Peter Behrman (Swedish National Road Administration). Describing the Dutch policy, Mr Boone referred to three requirements that were set: minimising the delays, maximising the safety of road users, maximising the safety of road workers. Among the measures specified in the Dutch guidelines, those suggested for improving safety of workers include: formulation and implementation of guidelines for the layout of work sites; the organisation of a road work (the application of temporary systems); the use of technical equipment; education and training for road workers; giving briefings before starting a work. Finally, examples of rules of the Dutch practice include: the (traffic arrangements and measures used for the) 3-1 system; the introduction of a 60-cm free space/zone between machines/vehicles (of the work site) and the barrier or other separating element; the provision of a buffer zone between the lane closure and the starting point of the workzone; the definition of the required lane width (especially in contraflow systems); the mandatory use of lane signalling in the case of lane closure; the use of a special type of crash attenuators in temporary situations and mobile lane closures. Referring to Swedish practice Mr Behrman noted that the target of the Swedish national traffic policy is "vision zero". Safety is considered at two levels: safety for road workers and safety for road users. The basis of the policy is training at all levels. Training is compulsory for workers and road managers. Swedish practice also includes: the use of mass media to increase public awareness and inform about particular problems related to road work zones; giving greater responsibility to the site manager; carrying out unannounced spot checks. Regarding the safety measures (for class A roads), Swedish standards specify the utilization of sturdy, energy-absorbing physical barriers, the removal of non-anchored heavy objects in support signs at road sites, the use of class 2 high-reflective material on all road signs at work sites and the mandatory use of approved high-visibility fluorescent clothing that fulfil special requirements. Regarding the procedures, a traffic arrangement plan is drawn up by the contractor before the commencement of the road works, specifying the location of road signs and additional safety devices. The plan is checked and approved by the road manager. The contractor is also responsible for maintaining the round the clock function of the signs and keeping accurate records of any changes. Actions towards the improvement of current practice include collection of relevant rules in a single document, gaining knowledge on accident causation at work zones through accident studies, raising the status of the workers, enhancement of the quality of the traffic arrangement plans, and promotion of uniformity of work site marking throughout the country. The following are some of the main issues raised in the ensuing discussion:
Towards the ARROWS Framework The ARROWS Workshop was foreseen as a crucial milestone, marking the mid-term of the project's life-cycle. To this end, the Workshop was meant to provide an initial sketching of the Handbook in broad terms by identifying the fundamental principles for its structure, content and style. The final session, titled "Towards the ARROWS Framework", was specifically dedicated to the sketching of the end-product of the project. To this end, two presentations were provided, by Mr Pavel Tucka (CDV) and Dr Wolfgang Schulte (BAST) respectively. Both presentations dealt with the issues of the content and structure of the handbook and of the necessary amendments (innovations) to the current state-of-practice. They identified certain key points concerning the layout and the signing of Road Work Zones, paying particular attention to the issues of:
The session and the Workshop ended with an exercise involving all the participants. This exercise was targeted to the sketching of the "Practical Handbook" and, within that, the participants were asked to freely fill in two lists as briefly as possible. The lists were entitled "What the handbook should be" and "What the handbook should not be". The unstructured and brief type of the participants' input was commanded by the necessity to record all the views stemming from people with different expertise and representing different bodies with varying perspectives. After having filled in the aforementioned lists, the entries of the "should be" list were classified in three entities, dealing with format, concept and content. A basic underlying principle for the aforementioned classification was the unanimous belief that the handbook will in any case be a pre-normative tool and thus had to be flexible to achieve an acceptable degree of usability among the European countries - under the principle of subsidiarity. The "should not be" list entries were also classified into four entities, namely: quantity of contained text; format of presentations of the respective safety measures; content topic; and innovative character. The concept of flexibility mentioned above was fully confirmed by the nature of the entries, where the participants proposed a handbook which would be: brief, containing many explanatory pictures and layouts, portable, user-friendly, comprehensive, accessible and modular. Moreover, it is envisaged to provide adequate details for the implementations of the proposed measures, to cover (in the sense of guidelines) the identified training gap (especially concerning the road workers), to provide a "Quality Control" check list and to allow for procedures of the "ask yourself" type. In conclusion, it was mentioned that the two-day Workshop revealed certain "white holes" in the current state-of-the-art and state-of-practice, and the need for actions - in the sense of targeted research projects to cover the gaps - was emphasized. |