Performance-Specified Maintenance Contracts Adding Value Through Improved Safety Performance Mike Manion and Susan L. Tighe To date, the contracts have been let for periods of 10 years. The rationale for this has been that it is a period approaching the typical life of a bituminous surface and the economic life of major plant items, and it is long enough for a sufficient transfer of risk to the contractor. It is also the upper bound of the period to which politicians are prepared to commit. The New South Wales Roads and Traffic Authority initiated the model in 1994. At the time the agency was aware that its maintenance budget was starting to exceed its construction budget; however, unlike construction, the agency had little control over costs or output. At that time, most maintenance was carried out by day labor, with some specialist services, such as spray sealing and asphalt, contracted out to supplement internal resources. Such contracting, although producing immediate savings, did not deliver longer-term benefits. Contract specifications could be met during the contract period and through the defects liability period, but the treatments were not ensured of achieving their design life. Further, the nature of public spending at that time meant that often large amounts of work were carried out in the southern hemisphere’s cooler months of May and June to meet a June financial year close. Typically road managers would hold back on projects until late in the financial year so the projects could be canceled if overexpenditure occurred in other areas. The public funding system did not lend itself to sound pavement management practice. Through the performance-specified contract (PSMC) model, these problems could be addressed. The successful contractors would be awarded a contract substantial enough to invest in and could manage their spending to meet the performance criteria for the least cost. The government agency received the benefit of reduced maintenance and administration costs, surety of budget programs, surety of levels of service, and sharing of risk. The initial Sydney, Australia, contract is still considered to be successful after 9 years of operation. Other Australian states have followed, as has New Zealand. Each agency is reviewing the process and making improvements to the base contract concept. The contract model has been developed substantially in New Zealand. This country already delivers its entire nationally funded road construction, maintenance, and operation program through contractors and consultants engaged on commercial contracts. These are let in accordance with the national competitive pricing procedures. The state highway network is administered by Transit New Zealand with the funding controlled by Land Transport New Zealand. Both are statutory authorities reporting to the Ministry of Transport. As part of its national services procurement strategy, Transit New Zealand has subdivided the state highway network into network management areas, each managed by a network management consultant. The consultant then manages the tendering process to engage a
In Australia and New Zealand, there has been a movement toward the private-sector delivery of road maintenance and management by using the performance-specified contract (PSMC) model. These are long-term contracts tendered competitively with a lump sum price. Initially the contracts concentrated on the physical attributes of the network that had to be maintained for the contract period. However, as these contracts matured, a reduction in the crash rates was observed. It was considered that the successful operation of a PSMC contributed to this reduction. By using data and calculation methods developed by Land Transport New Zealand and applying social costs for crashes normally used for justifying capital projects, it can be seen that the social cost of crashes is being reduced at a significantly greater rate on the PSMC 001 network than on the remainder of the state highway network. The value of savings ahead of the national trend has been more than NZ$31 million for a 3-year period. The contractor’s performance is measured on the social cost of crashes that occur on the network, regardless of crash causation. To keep the contractor motivated, the contract includes provisions to adjust the contract payments as based on the safety performance. This approach requires a fundamental shift in the attitude of the contractor, moving from a reactive position to a new position of prevention with particular attention on improved safety. Performance data from a 7-year contract and a 3-year contract from New Zealand are presented. Improved safety performance has become a hallmark in these contracts, and safety performance continues to improve through innovations and commitment.
During the past decade, there has been a movement in Australia and New Zealand toward engaging contractors to manage and maintain road networks for a defined period and for a lump sum amount. The lump sum is intended to include, as a minimum, the total agency cost of maintaining the network to the agreed level of service criteria. There are variations around this theme to cover such issues as the amount of weather damage or traffic growth risk that the contractor is to manage. Some contract models have the contractor also managing the development of the network and controlling access to it by other parties, such as developers and utility organizations. In such cases, the contractor fulfills almost all the roles previously carried out by the road agency.
M. Manion, Transfield Services Ltd., 15–19 Ruakura Road, Hamilton, New Zealand. S. L. Tighe, Department of Civil Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1 Canada. Corresponding author: S. L. Tighe,
[email protected]. Transportation Research Record: Journal of the Transportation Research Board, No. 1990, Transportation Research Board of the National Academies, Washington, D.C., 2007, pp. 72–79. DOI: 10.3141/1990-09
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network maintenance contractor responsible for the general maintenance and other contractors to perform specialist functions, such as pavement reconstruction and surfacing. The network management consultant then manages the network and oversees the activities of the contractors so that the network aims are delivered (1). With the advent of the PSMC contracts, all these functions were combined into one contract, with the benefit of contracted performance commitments for a fixed contract price. This makes the contractor responsible for the management of the network as well as the delivery of services. The model has a strong potential to optimize public–private partnerships. It rewards contractors who work efficiently and deliver a high-quality product. The real savings, or in contractors, terms profit, come through two areas—the reduction of duplication in management and supervisory staff and the elimination of rework. The fewer treatments required, the less money spent. Similarly, if issues such as drainage and surface waterproofing are maintained, the contractor reduces deterioration and again spends less. Provided that the appropriate performance measurement systems are in place, the PSMC mechanism can bring out the best in people by driving the right behaviors and rewarding the application of sound engineering and asset management practice. Initially the performance was specified in terms of asset condition, but as the model develops, asset performance is being considered.
ASSET PERFORMANCE MEASURES The contracts operate by using a set of performance measures. In these, the road controlling authority identifies the physical attributes of a highway network that are required for the authority to meet its level of service obligations to road users. Under the PSMC model, the network performance requirements can be summarized into the following areas: • Asset preservation – Pavement structure as measured with a falling weight deflectometer – Pavement cracking – Surface remaining life • Pavement surface – Roughness – Rutting – Surface texture – Surface skid resistance • Drainage systems – Pits – Culverts – Open drains • Traffic facilities – Traffic signs – Road marking – Barriers – Lighting • Visual amenity – Litter control – Grass cutting – Tree maintenance – Weed management The performance levels typically are defined with both a specified intervention level and a response time within which defects must be
73
corrected. Many of the specified performance measures are intended to maintain the designed standard of safety on the highway. Under the contract, the contractor is required to establish systems with which to measure and report on the condition of these assets. This has led to higher levels of inspection and surveillance. The principal retains an audit function on specific systems and outputs as well as annual audits covering all aspects of service delivery and the achievement of the desired outcomes.
CONTRACT PERFORMANCE These contracts operate through a continuing measurement and review system. Certain works are planned to occur reactive to the inspection results. Other work occurs as part of a planned program, but with the outputs measured and the program amended as required. As the contracts progress, the contract management team and the client have a good understanding of the overall condition of the network. Included in the scope of the New Zealand contracts is the requirement to manage the future development of the network. The contracts also require that the contractor conduct a preliminary accident investigation at all fatal and selected serious injury crash sites. In other procurement models, consultants who can be removed from the network maintenance operations carry out these investigations. For example, under other procurement models, the degree of reflectivity of the line marking is not the responsibility of any party. The work is performed at set times during the year. Under the PSMC model, the marking must be maintained to a specified level. The contractor must then make an assessment of this as part of the crash investigation. It should be noted that the contractor’s investigation is parallel to a police investigation, with the latter being adopted as the prime source of evidence in any trials. However, the contractor through this investigation process becomes more exposed to the realities of road trauma (2).
ROLE OF SAFETY Road accidents result in substantial property damage and economic losses. Although a number of safety measures, including stronger safety laws and public awareness safety campaigns, have been implemented to reduce road accidents, the total deaths each year are still more than 90% of the annual total transportation fatalities (3). Consequently, it is important to research more effective and efficient ways to reduce accidents and save lives on roadways. Many investigations have proved that individual road accidents are complex events involving a variety of factors, such as road geometrics, pavement-related engineering, driver behaviors or human factors, traffic operations, safety measures, speed limits, and vehicle functions. Therefore, analysis of road accidents should involve comprehensive consideration of all safety factors or parameters associated with individual road accidents. These accidents or collisions can be the result of the interaction of four elements, as shown in Figure 1. The venn diagram constructed shows the relationship among four road safety factors. Individually, the environment, road, driver, and vehicle influence road safety. In addition, interaction effects are related to these four factors, as shown by the hatched overlap areas of the factors. The venn diagram is particularly suited to characterizing the occurrence of the interplay of the environment, within which the driver, vehicle, and road exist. For example, single-vehicle accidents can occur as a result of mechanical
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•Age
•Type of vehicle (car, van, etc.)
•Gender
•Vehicle size
•Driving record
•Vehicle weight
•Distraction factors Driver Vehicle Interactions
Road
•Road geometry
•Weather conditions •Traffic flow, speed limit
Environment
•Time of day
•Maintenance standards
•Pavement markings
FIGURE 1
•Pavement factors
Road safety factors and interactions (3).
failure, driver distraction, or slippery, wet conditions. Each of the elements for each accident has a different influence on or explanation for the accident (4).
RESULTS As the PSMC 001 contract progressed, it was noted initially that the number of crashes on the network was dropping. The findings came through general observations in the normal course of network management. Following this, a review was undertaken of the national road accident database. In New Zealand, the Land Transport Safety Authority (LTSA) operates a national crash analysis system, in which all police reports of motor vehicle accidents are recorded and coded by location, movement types, and crash factors. The goal is to give road controlling authorities data that can be used to prevent future occurrences. The accidents were each assigned values on the basis of their recorded severity. Economists working for the national transport funding agency Transfund have calculated the social cost of crashes. The costs are intended to be used in the economic evaluation of road improvement projects as part of the justification through a benefit–cost ratio comparison. The values used throughout this paper are average values for all vehicle types and all speeds and are in New Zealand dollars. They have been calculated from Transfund’s 1998 project evaluation manual. Since that time the values have increased to reflect rising costs. However, it was decided for consistency to use them as a basis for analysis in this work, because the primary interest here is to examine the relative costs to various crash or accident types across the analysis years: Crash Type
Value
Fatal Serious injury Minor injury Noninjury
$2,200,000 $210,000 $13,000 $1,200
The following are definitions of crash and accident types: 1. Fatal injuries—a crash causing injuries that result in death within 30 days of the crash; 2. Serious injuries—fractures, concussion, internal injuries, severe cuts and lacerations, severe general shock necessitating medical treatment, and any other injury involving removal to and detention in hospital; 3. Minor injuries—injuries, such as sprains and bruises, not requiring hospital treatment; and 4. Noninjury crashes—statistics concerning crashes involving property damage only. This review showed that since the commencement of the contract, there had been a reduction in the number and severity of accidents on the network. To show the effects of this, a measure of social cost was developed. The social cost over time, monitored by the contractor at all times, is shown in Table 1 in terms of an annual dollar amount compared to the national average. The trend value is shown for the last 5 years. Clearly this shows that the social cost of crashes is reducing at a faster rate than that on the total state highway network. To keep the analysis simple and to reduce the possibility of introducing inaccurate date, it was decided to make no account of the increase in vehicle kilometers traveled in either the PSMC 001 or the national highway networks. To understand better the reasons for this trend, an analysis was performed to identify the types of crashes that are decreasing. The method used was based on that used by LTSA to determine the effectiveness of improvements that have been identified and implemented at specific sites with high crash rates that have been identified in crash reduction studies (5). LTSA established a national crash reduction study program in 1985 to undertake a continuous program of systematic investigation of all roads in New Zealand. A modified version of the crash reduc-
Manion and Tighe
TABLE 1
75
Comparison of Social Cost of Accidents
Year
1998
PSMC 001 National
1999
2000
2001
Trend
$27,321,800
$25,722,000
$14,651,000
$19,519,000
$12,816,400
$17,514,000
−35.90%
$772,087,000
$671,374,200
$684,016,800
$608,590,400
$691,440,600
3.96%
METHODOLOGY FOR ANALYSIS All the crash data (from 1996 to 2003) used are from the LTSA crash analysis system and are shown in Table 2 (5, 6). To carry out the analysis, 1996–1998 is defined as the before period, 1999–2000 as the treatment period, and 2001–2003 as the after period. Here, the treatment period is the first 2 years of the PSMC 001 contract. In addition, there were some modifications on the traditional crash reduction study; the details are discussed later. The review network covers the original contract network: SH 3 RP 5/4.40 to RP 218/9.55, SH 4 RP0/0.00 to RP 61.88, SH 30 RP0/0.0 to RP 47/14.14, SH 31 RP0/0.0 to RP 47/9.29, and SH 37 0/0.0 to RP 0/7.34. Equations 1 and 2 are used to calculate the costs and percent reductions (7). ControlAfter CrashesCostExpected = BeforeCrashesCost × ControlBefore
where CrashesCostExpected = expected social cost of all injury crashes on PSMC 001 highway network in after period, assuming treatment had no effect; BeforeCrashesCost = actual social cost of all injury crashes on PSMC 001 highway network in before period; ControlBefore = actual social cost of all injury crashes on all highway network in New Zealand during before period; and ControlAfter = actual social cost of all injury crashes on all highway network in New Zealand during after period; and AfterCrashesCost = actual social cost of all injury crashes on PSMC 001 highway network in after period. From Equation 1 and the data in Table 3, one can do the following calculation (dollar amounts are in U.S. currency): ⎛ 19998 ⎞ NetworkCostExpected = ⎜ ∑ NetworkSocialCost⎟ ⎝ 1996 ⎠ ×
× (1)
(CrashesCostExpected − AfterCrashes) × 100% (2) CrashesCostExpected
Social Cost of All Injury Crashes, 1996 to 2003
Year
No. of Injury Crashes
Social Cost
National Highway Network
1996 1997 1998 1999 2000 2001 2002
99 96 75 104 94 115 103
$29,875,000 $35,609,000 $27,179,000 $25,566,000 $14,501,000 $19,345,000 $12,628,000
$768,853,000 $804,033,000 $657,281,000 $763,621,000 $663,033,000 $674,826,000 $599,438,000
2003
112
$17,316,000
$682,131,000
NationalSocialCost 2001− 2003 NationalSocialCost1996−1998
= ( 29, 875, 000 + 35, 609, 000 + 27,179, 000 ) 1, 956, 395, 000 = $81, 711, 008 2, 230,167, 000
(3)
2003 ⎛ ⎞ ⎜⎝ NetworkCostExpected − ∑ SocialCost⎟⎠ 20001 %Reduction = × 100% NetworkCostExpected
= TABLE 2
2003
$665,119,400
tion study was used to allow a more detailed review of the PSMC 001 highway network. This compares the performance of the network before the commencement of the contract and for the most recent years, with the aim of determining which particular areas are seeing significant reductions in the number and severity of crashes. This analysis thus accounts for trends that may be the result of national factors, such as increased enforcement programs or community advertising programs. In addition, as the crash analysis system matures, and as the reporting officers become more proficient, the level of reporting of crashes increases. This results in a decrease in the rate of underreporting. This will have a greater effect on the lower-severity crashes, leading to an apparent increase in the number of these crashes.
%Reduction =
2002
81, 711, 008 − 49, 289, 000 × 100% 81, 711, 008
= 38.99% reduuction in dollars = $81, 711, 008 − $49, 849, 400 = $31, 861, 609
(4)
Equations 1 through 4 illustrate the whole process for calculation of the reduction of the social cost of all the injury crashes on PSMC 001. Reduction calculations were undertaken on severity, movement type, and daylight. All the calculations undertaken conform to this concept. The LTSA methodology has been modified to suit a network analysis, and a brief summary of the differences is found in Table 4.
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TABLE 3
Reductions in Crash Movement Type
Movement Type
Expected Social Cost
Actual Social Cost
Reduction Rate (%)
$28,945,441 $26,768,064 $9,006,125 $7,110,648 $3,604,353
$21,389,000 $14,791,000 $721,000 $1,531,000 $2,737,000
26.11 44.74 91.99 78.47 24.06
Cornering Head on Overtake and lane change Lost control and off road Crossing (vehicle turning)
ously. The following sections attempt to offer other possible rationales for these observations.
COMPARISON OF MOVEMENT TYPES With this methodology, a comparison was calculated between the estimated costs as based on the precommencement crash history as adjusted by national trends on the entire highway network and the actual accident costs recorded on the PSMC 001 network. This comparison was undertaken over the five key recorded movement types that make up 90% of the recorded crashes. Key findings of this study are shown in Table 3. From this it can be seen that the network is performing significantly better than the rest of the national highway network in reducing the social cost of crashes in these areas. A review was also undertaken comparing day and nighttime crashes, and the results were as follows: Expected social cost Actual social cost Reduction rate
Day
Night
$59,649,827 $30,587,000 48.72%
$21,488,307 $18,702,000 12.97%
Network Accountability Whatever can be measured can be improved on—at least that is the goal of this work. By simply identifying highway safety as a measure, its importance is elevated within the entire organization. Once it is measurable, people at all levels focus on what can be done to improve the measured outcomes. The improvement of network safety becomes a strong motivator to the network management team to ensure that they continue to carry out their duties to the best of their abilities. The fundamental difference in the approach is changing from a defensive view of crashes, which aims to attribute all responsibility for the crash on the driver, to an investigative approach, wherein they may challenge themselves to identify what more could have been done to prevent crashes, which would lead to a reduction in the performance measure.
POSSIBLE REASONS FOR IMPROVED PERFORMANCE
Responsiveness
It is acknowledged that most road crashes are caused by driver error. It is also known that there will continue to exist, on the road network, drivers who suffer some degree of impairment. It is assumed that these factors will continue to exist across the country. However, as there appeared to be a difference between the performance of the PSMC 001 network and the national trends, it is worth considering what influences may be acting on this network in comparison to the rest of the country. The statistics reinforce the fact that the contractor is acting in a more proactive manner and is taking the role seri-
Under the PSMC format, there are strict controls for the identification and rectification of defects. The contract details response times for all defect types and then requires that these be measured. These measures are collected constantly and reported monthly, giving the contract management and hence the client a high level of assurance that these are being met. This reduces the period of exposure of road users to these defects. Further, in the original contract, key performance measures were not necessarily the most appropriate, and every effort was made to reduce the response
TABLE 4
LTSA Versus PSMC 001 Method
LTSA Method
PSMC 001 Network Method
There is no treatment period defined.
Divide the time span from 1996 to 2003 into 3 periods. 1999–2000 was defined as treatment period. The treatment period covers the first 2 years (1999–2000) of our PSM C001 contract.
The treatment was regarded as a stand-alone point when a discrete safety improvement was implemented. 5 years’ crash data were normally used as the Before Crashes. Number of crashes is used for the reduction calculation. In after period, it is assumed that there is no further treatment. Thousands of crash monitoring sites are defined. The final crash data were achieved by summing up all the data from these sites.
3 years’ crash data (1996–1998) were used for calculation. Social cost is used for the reduction calculation as the reduction in severity is a key improvement as well as an improvement in the crash reporting. PSMC 001 is a 10-year contract, and treatment is ongoing in the after period (2001). The crash data are from the whole PSMC 001 highway network.
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times for the crews to reduce the time that the public would be exposed to the hazard.
measures on these areas cover both average conditions to be maintained as well as localized outliers that must be addressed within response times.
Improved Signage Conspicuity Improved Linemarking Condition On the highways studied in this paper, road signage plays a key role in attempting to modify driver behavior. Although drivers make errors of perception and judgment, it is possible to lessen this through better use of signage. There are various elements to this. The signage is maintained on a block section approach, with each sign face being cleaned and encroaching vegetation trimmed on a 6-month basis. This simple function ensures that the signs remain visible and reflective. Sign condition is also monitored by 6-month condition inspections. These are reviewed constantly to ensure that the signage matches the inventory, that is, that signs are not missing and that they comply with condition standards. Evidence of the improvement in signage condition is as follows: Year
% Nonconforming Signs
1999 2000 2001 2002 2003
7.44 1.49 0.78 0.32 0.27
Signage is upgraded as a part of routine sign maintenance. This includes the use of larger signs with intensity reflective materials.
Improved Pavement Condition Many of the contract performance measures detail the condition of pavement, as shown in Table 5. As noted, all key performance measures—roughness, rutting (%), surface texture (mm), and SCRIM—have shown improvements. [Roughness is network average roughness measured in National Association of Australian State Road Authorities counts; rutting is the percentage of network with rutting greater than 20-mm wheelpath; surface texture is the network average mean profile depth (mm); and SCRIM is the percentage of sites below investigation level for Site Categories 1 through 4.] The contract operates a substantial pavement treatment program consisting predominantly of rehabilitation treatments and resealing works. During the contract term there has been a significant improvement of the network condition. However, it should be noted that Transit New Zealand has been working to improve the condition of the entire state highway network and that other networks with access to better quality local sealing aggregates have achieved greater improvements in the surface friction measurements. Thirty detailed
TABLE 5 Summary of Contract Performance in Improved Pavement Condition Key Performance Measure Roughness Rutting (%) Surface texture (mm) SCRIM (%)
1999
2000
2001
2002
2003
79.46 2.89 1.95
77.96 3.8 1.94
77.5 3.53 1.94
74.93 0.79 2.12
74.5 0.76 2.15
48.3
54.6
53.9
16.59
16.4
Before commencement of the contract, the network was marked in nonreflective alkyd-based paints. The contract specified a linemarking reflectivity of 100 milli candela lux/m2. The network is now marked with a waterborn paint system with average reflectivity of 190 mcd lux/m2 with the intervention level set at 150. It was expected that this would provide a greater improvement reduction in nighttime crashes; however, at this stage night crashes have been reduced by only 13%.
Ongoing Network Surveillance The contract team includes additional engineering support whose duty is to monitor network safety performance and to recommend improvements. The team constantly monitors the network, identifying problems and potential problems and proposing solutions. Further, the network inspectors monitor the network identifying deficiencies and opportunities for improvements. These are fed back to the engineering staff for a determination of the solution. This results in a higher degree of surveillance of the network. When an area causes concern, it can be investigated and solutions can be implemented more quickly, as the inspection, engineering, and field operations are controlled through one organization rather than several. This expedites the rectification of safety deficiencies. The contract team is then in a position to apply this to the subject sites and then to others that have a similar problem.
Intersection Improvements It is noted that one of the larger areas of improvement has been in the reduction of intersection crashes. At contract commencement, 45% of the side roads joining the highway network had no controls. This was identified and rectified. The side roads were then routinely inspected, and work was carried out to improve sight lines.
NETWORK SAFETY PERFORMANCE INDICATOR The results observed on the PSMC 001 contract showed that the success in delivering a network management and maintenance strategy could have an effect on the safety of the highway network. As the performance-specified maintenance contract model has developed, there has been increasing interest in the safety performance of the networks managed under this system. The safety performance is now being tracked in at least three contracts. In PSMC 001, it is being monitored as an internal measure to determine how the contract is performing, and although it is an item of interest for the contract team, it has no contractual status. On the PBC 001 BayRoads contract, a performance measure was included in the tender version of the contract that, among others, measured the number of crashes for which road factors was a cause. There were concerns at the time that only a small percentage of crashes are recorded with this as a crash factor and thus it would be difficult
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to manage. This would be exacerbated by the possibility for subjectivity in the assignment of key crash causes. The success or ongoing use of this measure is not known. On PSMC 005, the contractor that had been managing the PSMC 001 contract and observing a reduction in the crash index decided to offer it as a contract performance measure in the most recent contract. The measure is of interest in that it is the only one in the contract for which there is an adjustment of payments for performance. For the measure to be contractually robust, it must both reflect the actual situation on the network and be supported by objective input data. The numbers and types of crashes come from the Land Transport New Zealand crash analysis system. When the number of crashes is extended by the social cost for each crash, the sum of the products is the social cost of crashes for the network. This has been refined for use in a contract by adopting a 3-year rolling average to reduce the effect of the random fluctuations that appear in data of this type. Further, the social cost has been divided by the total vehicle kilometers traveled on the network to produce a network safety indicator. This adjustment was included to cover the situation of traffic volume increases, masking a gradual safety rate improvement. The traffic information is readily available from the pavement management system. The specific formula from the contract is as follows: network safety index =
ACn − 2 + ACn −1 + ACn 3 × VKM n
(55)
where ACn−2 = social cost of crashes in year n − 2; ACn−1 = social cost of crashes in year n − 1; ACn = social cost of crashes in year n; j
VKMn = 365 ×
∑ [ AADT × l ]; i
i
i =1
n = year for which network safety index is being determined; li = length of section of network where traffic volumes are consistent and represented by data from count site; AADTi = annual average daily traffic from count site within or relevant to length li; and j = total number of lengths, li, that summed together equal the total length of the network. The contract that uses this formula began in April 2003. The tender offer was to reduce the safety performance indicator by 5% per year for each year of the contract. Indications after 3 years are that the index is working. Its presence alone heightens the importance of highway safety to the management team and the field staff. The entire contract delivery team of managers, engineers, and field crews is strongly focused on reducing crashes. They are aware that all their actions, from trimming vegetation and cleaning signs through the selection of surfacing treatments and the installation of new assets, may reduce the incidence or outcome of a highway crash. Details of the actual performance are as follows: • Total 3-year social cost of crashes – 2001–2003, $68,638,200 – 2002–2004, $64,966,400 – 2003–2005, $66,452,000
• Vehicle kilometer (vkm) data Year
vkm
Difference
%Difference
2002 2003 2004 2005
638,102,529 669,338,799 711,870,891 754,402,983
31,236,270 42,532,092
0.047 0.060
• Network safety index Year
vkm
2003 2004 2005
0.0342 0.0304 0.0294
Vehicle kilometers for 2005 were estimated on the basis of a 6% increase from previous years. The 2005 traffic counts are not available; therefore a true value for 2005 vehicle kilometers cannot be determined.
LIMITATIONS The results reported in this paper reflect the observations and experience gained in the operation and management of highways with the following features. Traffic volumes typically are in the range of 2,000 to 15,000 vehicles per day for the total carriageway, with only a small section having more than this. Both networks consist typically of two-way, two-lane rural highways passing through undulating terrain with numerous curves, many of which have design speeds that are lower than the prevailing speed environments. The PSMC 005 contract has approximately 18 km of motorway. The experience to date does not cover a high-volume, welldeveloped network. High levels of network development, such as divided carriageways, grade-separated interchanges, long-radius curves with appropriate design speeds, and carriageway lighting, are most likely to reduce the reliance of network safety outcomes on the level of maintenance effort. Although some benefit will be derived from maintaining the infrastructure to its designed level of service, the effect of this is as yet unknown. It should be noted that New Zealand operates under a different personal injury liability law than do other jurisdictions. In New Zealand, the rights of individuals to sue are limited. Instead, individuals are reimbursed actual costs through the Accident Compensation Commission. The accident compensation scheme provides accident coverage for all New Zealand citizens, residents, and temporary visitors. In return, people do not have the right to sue for personal injury, other than for exemplary damages. This scheme 1. Provides cover for injuries, no matter who is at fault; 2. Eliminates the slow, costly, and wasteful process of using the courts for each injury; 3. Reduces personal, physical, and emotional suffering by providing timely care and rehabilitation that gets people back to work or independence as soon as possible; 4. Minimizes personal financial loss by paying weekly earnings compensation to injured people who are unable to work; and 5. Focuses on reducing the causes of these problems—the circumstances that lead to accidents at work, at home, on the road, and elsewhere.
Manion and Tighe
The Injury Prevention, Rehabilitation, and Compensation Act is the principal act under which the Accident Compensation Corporation operates. With the protection of this act, people responsible for managing roads can focus on detailed investigation of crashes to find what may have been preventable rather than collecting proof that the accident was not preventable. Outsourcing in other areas may not enjoy this degree of protection.
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Following this result, a trial is under way on PSMC 005 that includes the provision of a network safety indicator as a contract performance indicator that directly links safety performance on the highway network to the contract payments. This indicator drives the behavior of the contract team to look for ways to reduce the number and severity of crashes recorded on the contract network.
REFERENCES CONCLUSION The degree of safety of a rural highway is dependent to some degree on the quality of the maintenance planning and service delivery. The PSMC contract model, through a performance specification and measurement system, places the responsibility for these activities with one organization, the maintenance contractor. Thus, this organization can influence the safety performance of the contract network. After 7 years of work on the PSMC 001 contract and 3 years on PSMC 005, there has been an appreciable improvement in the network condition. This has been measured through the contract performance measurement system. Simultaneously, there has been a reduction in the social cost of crashes on the network as measured through the national crash analysis system. This reduction has been compared to national trends on the remainder of the national state highway network, and the improvement is significantly better than the national figures.
1. Manion, M. E. Role of New Data Collection Technology in Performance Specified Maintenance Contracts. Presented at 82nd Annual Meeting of the Transportation Research Board, Washington, D.C., 2003. 2. Tighe, S., M. Manion, J. Yeaman, I. Rickards, and R. Haas. Using Performance Specified Maintenance Contracts: Buyer/Seller Bewared. Journal of Infrastructure, (forthcoming). 3. Tighe, S., N. Li, L. C. Falls, and R. Haas. Incorporating Road Safety into Pavement Management. In Transportation Research Record: Journal of the Transportation Research Board, No. 1699, TRB, National Research Council, Washington, D.C., 2000, pp. 1–10. 4. Tighe, S., L. Cowe Falls, and J. Morrall. Integrating Safety with Asset Management Systems. Presented at Fifth International Conference on Managing Pavements, Seattle, Wash., 2001. 5. Crash Analysis System. Land Transport Safety Authority, Wellington, New Zealand. www.ltsa.govt.nz/roads/crash/overall-results-2003-02.html. 6. Crash Reduction Studies. Land Transport Safety Authority, Wellington, New Zealand. www.ltsa.govt.nz. 7. New Zealand Accident Compensation Commission. www.acc.govt.nz. The Pavement Management Systems Committee sponsored publication of this paper.
