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Road Design for Future Maintenance: Life-cycle Cost Analyses for Road Barriers
KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The cost of a road construction over its service life is a function of design, quality of construction as well as maintenance strategies and operations. An optimal life-cycle cost for a road requires evaluations of the above mentioned components. Unfortunately, road designers often neglect a very important aspect, namely, the possibility to perform future maintenance activities. Focus is mainly directed towards other aspects such as investment costs, traffic safety, aesthetic appearance, regional development and environmental effects.

This doctoral thesis presents the results of a research project aimed to increase consideration of road maintenance aspects in the planning and design process. The following subgoals were established:

  • Identify the obstacles that prevent adequate consideration of future maintenance during the road planning and design process; and
  • Examine optimisation of life-cycle costs as an approach towards increased efficiency during the road planning and design process.

The research project started with a literature review aimed at evaluating the extent to which maintenance aspects are considered during road planning and design as an improvement potential for maintenance efficiency. Efforts made by road authorities to increase efficiency, especially maintenance efficiency, were evaluated. The results indicated that all the evaluated efforts had one thing in common, namely ignorance of the interrelationship between geometrical road design and maintenance as an effective tool to increase maintenance efficiency. Focus has mainly been on improving operating practises and maintenance procedures. This fact might also explain why some efforts to increase maintenance efficiency have been less successful.

An investigation was conducted to identify the problems and difficulties, which obstruct due consideration of maintainability during the road planning and design process. A method called “Change Analysis” was used to analyse data collected during interviews with experts in road design and maintenance. The study indicated a complex combination of problems which result in inadequate consideration of maintenance aspects when planning and designing roads. The identified problems were classified into six categories: insufficient consulting, insufficient knowledge, regulations and specifications without consideration of maintenance aspects, insufficient planning and design activities, inadequate organisation and demands from other authorities. Several urgent needs for changes to eliminate these problems were identified.

One of the problems identified in the above mentioned study as an obstacle for due consideration of maintenance aspects during road design was the absence of a model for calculating life-cycle costs for roads. Because of this lack of knowledge, the research project focused on implementing a new approach for calculating and analysing life-cycle costs for roads with emphasis on the relationship between road design and road maintainability. Road barriers were chosen as an example. The ambition is to develop this approach to cover other road components at a later stage.

A study was conducted to quantify repair rates for barriers and associated repair costs as one of the major maintenance costs for road barriers. A method called “Case Study Research Method” was used to analyse the effect of several factors on barrier repairs costs, such as barrier type, road type, posted speed and seasonal effect. The analyses were based on documented data associated with 1625 repairs conducted in four different geographical regions in Sweden during 2006. A model for calculation of average repair costs per vehicle kilometres was created. Significant differences in the barrier repair costs were found between the studied barrier types.

In another study, the injuries associated with road barrier collisions and the corresponding influencing factors were analysed. The analyses in this study were based on documented data from actual barrier collisions between 2005 and 2008 in Sweden. The result was used to calculate the cost for injuries associated with barrier collisions as a part of the socio-economic cost for road barriers. The results showed significant differences in the number of injuries associated with collisions with different barrier types.

To calculate and analyse life-cycle costs for road barriers a new approach was developed based on a method called “Activity-based Life-cycle Costing”. By modelling uncertainties, the presented approach gives a possibility to identify and analyse factors crucial for optimising life-cycle costs. The study showed a great potential to increase road maintenance efficiency through road design. It also showed that road components with low investment costs might not be the best choice when including maintenance and socio-economic aspects.

The difficulties and problems faced during the collection of data for calculating life-cycle costs for road barriers indicated a great need for improving current data collecting and archiving procedures.

The research focused on Swedish road planning and design. However, the conclusions can be applied to other Nordic countries, where weather conditions and road design practices are similar. The general methodological approaches used in this research project may be applied also to other studies.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Intstitute of Technology , 2011. , xiv, 79 p.
Series
, TRITA-VBT, ISSN 1650-867X ; 2011:04
Keyword [en]
road maintenance, road management, road planning, road design, life-cycle cost, road barrier, guardrails, cable barrier, road traffic injuries, barrier collisions and barrier repair costs.
National Category
Civil Engineering
Identifiers
URN: urn:nbn:se:kth:diva-31984ISBN: 978-91-7415-902-8OAI: oai:DiVA.org:kth-31984DiVA: diva2:407903
Public defence
2011-04-27, K2, Teknikringen 28, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20110407

Available from: 2011-04-07 Created: 2011-04-01 Last updated: 2014-06-16Bibliographically approved
List of papers
1. EVALUATION OF ATTEMPTS FOR EFFICIENT ROAD MAINTENANCE - KNOWLEDGE COMPILATION
Open this publication in new window or tab >>EVALUATION OF ATTEMPTS FOR EFFICIENT ROAD MAINTENANCE - KNOWLEDGE COMPILATION
2010 (English)In: BALT J ROAD BRIDGE ENG, ISSN 1822-427X, Vol. 5, no 4, 229-239 p.Article in journal (Refereed) Published
Abstract [en]

The objective of this study was to compile experiences regarding efforts by road authorities to satisfy the needs for efficient maintenance and the results of such efforts. The extent to which maintenance aspects are considered during road planning and design, as a potential for improvement of maintenance efficiency is studied. The study shows that such efforts have in many cases resulted in reduced maintenance costs. However, there are also indications that maintenance standards in some cases have declined, as the focus has been on reduction of the rate of recurring maintenance activities and prioritisation of some maintenance measures, e.g. winter maintenance, over other maintenance measures, e.g. pavement maintenance. The study also shows that efforts towards increased maintenance efficiency have one thing in common - namely that the main focus has been on improving operating practices and maintenance procedures. Road authorities have mostly ignored the improvement potentials that exist during the planning and design process through consideration of the interrelationship between geometrical road design and maintenance.

Keyword
efficient highway maintenance, road design for lower maintenance, life-cycle cost analysis for roads
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-29723 (URN)10.3846/bjrbe.2010.31 (DOI)000285818800006 ()2-s2.0-78651396016 (ScopusID)
Note
QC 20110214Available from: 2011-02-14 Created: 2011-02-14 Last updated: 2011-04-07Bibliographically approved
2. Road Design for Future Maintenance Problems and Possibilities
Open this publication in new window or tab >>Road Design for Future Maintenance Problems and Possibilities
2008 (English)In: Journal of transportation engineering, ISSN 0733-947X, Vol. 134, no 12, 523-531 p.Article in journal (Refereed) Published
Abstract [en]

This paper presents an investigation conducted to identify obstacles that prevent sufficient consideration of future road maintenance needs during the road planning and design phase. The investigation focuses on the road planning and design process within the Swedish Road Administration. For this reason the results are applicable for Nordic conditions concerning road design, maintenance, and climate. However, the results focus on general aspects of the planning and design process and ought to also be valid for other conditions outside the Nordic countries. The investigation was carried out using a method called "change analysis," which consists of complementary steps for the analysis of problems, processes, and goals in order to identify necessary changes. The investigation identified several problems within the road planning and design process related to consulting, knowledge, planning and design activities, regulations, organization structure, and demands from other authorities. The identified problems, activities within the planning and design process, and goals for the process were analyzed. Based on these analyses the investigation identifies the most urgent needs for change in order to eliminate the problems that result in insufficient consideration of maintainability during the planning and design process.

National Category
Civil Engineering Mechanical Engineering
Identifiers
urn:nbn:se:kth:diva-33418 (URN)10.1061/(ASCE)0733-947X(2008)134:12(523) (DOI)000260940500004 ()2-s2.0-56449087064 (ScopusID)
Note
QC 20110505Available from: 2011-05-05 Created: 2011-05-05 Last updated: 2014-06-16Bibliographically approved
3. Road Barrier Repair Costs and Influencing Factors
Open this publication in new window or tab >>Road Barrier Repair Costs and Influencing Factors
2011 (English)In: Journal of transportation engineering, ISSN 0733-947X, Vol. 137, no 5, 349-359 p.Article in journal (Refereed) Published
Abstract [en]

This paper presents a study that examines repair costs for different road barrier types and factors that influence these costs. The analyses focused on w-beam and cable barriers used as median barriers. To some extent, pipe barriers, Kohlswa-beam barriers and concrete barriers were also studied. The influencing factors included in this study were: road type, speed limit, barrier type and seasonal effects. A case study was conducted in four regions of the Swedish Road Administration. Data were collected from 1625 barrier repairs carried out during 2005 and 2006. The results show that the number of barrier repairs and the average repair cost per vehicle kilometre are higher along collision-free roads than along motorways and 4-lane roads. The results also show that the number of barrier repairs and the average repair cost per vehicle kilometre are higher for cable barrier than for other barrier types. No conclusion can be drawn regarding influence of speed limits on barrier repairs and associated costs as the result from the regions are divergent and not statistically significant.

Keyword
Road barrier, highway maintenance, highway management, highway design, road design and highway engineering
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-31975 (URN)10.1061/(ASCE)TE.1943-5436.0000227 (DOI)000290481500008 ()2-s2.0-79955820772 (ScopusID)
Note
Uppdaterad från Accepted till Pubished(20110615) QC 20110407Available from: 2011-04-01 Created: 2011-04-01 Last updated: 2011-06-15Bibliographically approved
4. Assessment of Injury Rates Associated with Road Barrier Collisions
Open this publication in new window or tab >>Assessment of Injury Rates Associated with Road Barrier Collisions
2011 (English)In: Accident Analysis and Prevention, ISSN 0001-4575, E-ISSN 1879-2057Article in journal (Other academic) Submitted
Abstract [en]

This paper presents a study aimed at quantifying and comparing the risk of personal injuries associated with road barrier collisions. Documented data from actual barrier collisions, including post-impact collisions, in Sweden between 2005 and 2008 were analyzed. The analyses were based on the injury classification made by healthcare services. The injury rates, measured in number of injuries per vehicle kilometer travelled, were calculated for the different injury classes as a basis for evaluating barrier performance. The results show that the rate of injuries was higher due to collisions with flexible barrier systems, such as cable barrier, than with other semi-rigid and rigid barrier system, such as w-beam and concrete barriers. This result might be explained by a high rate of post-impact events, such as post-impact collisions, roll-overs and over-rides, associated with the placement and mechanical properties of the cable barriers. The study also showed a considerable difference in injury classifications made by the police and the healthcare services, as well as a considerable under-reporting of barrier collisions by the police.

Keyword
road barrier performance, injury rate associated with road barrier collision, guardrails, cable barriers
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-31979 (URN)
Note
QS 20120316Available from: 2011-04-01 Created: 2011-04-01 Last updated: 2012-03-16Bibliographically approved
5. Life-cycle Cots Analyses for Road Barriers
Open this publication in new window or tab >>Life-cycle Cots Analyses for Road Barriers
2011 (Swedish)In: Journal of transportation engineering, ISSN 0733-947XArticle in journal (Refereed) Published
Abstract [en]

This study aimed at applying and evaluating a new approach for analyzing life-cycle costs for road components during the road planning and design process. Road median barriers were chosen as an example. The approach is based on a method called "Activity-Based Life-Cycle Costing using the Monte Carlo Simulation" for managing future costs and the associated risks. The results show a potential for increasing efficiency throughout the road planning and design process by minimizing the life-cycle costs of road components. The results also show that implementation of life-cycle cost analyses in the road planning and design process is possible, but difficult, mainly due to lack of relevant data.

Keyword
life-cycle cost analyses for road barriers, road maintenance and road planning and design
National Category
Civil Engineering
Identifiers
urn:nbn:se:kth:diva-31983 (URN)
Note
QC 20110407Available from: 2011-04-01 Created: 2011-04-01 Last updated: 2011-04-07Bibliographically approved

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