RAA Highway Assessment. Eyre Highway

Transcription

1 June 2014

2 Prepared By Ian Bishop Date 06 June 2014 Traffic Engineer T: E: Approved By Charles Mountain Date 10 September 2014 Senior Manager Road Safety T: E: Revision History Rev Date Author Approver Comment 0 06/06/14 IAB CM Draft. A 10/09/14 IAB CM For Issue.

3 Contents Executive Summary 1 1 Traffic Volumes 4 2 Crash Statistics 5 3 Highway Geometry Lane Widths Sealed Shoulders Audio Tactile Line Markings 9 4 Pavement Performance Ride Quality Rutting Texture 14 5 Roadside Hazards Roadside Objects & General Hazards Embankments Edge Drop 17 6 Safety Barriers 18 7 Signs & Line Marking 18 8 Rest Areas 19 9 AusRAP Summary & Recommendations References 23 Appendix A Pavement Performance Factors 24 Appendix B AusRAP Safer Roads Investment Plan 28

4 Executive Summary The runs between Port Augusta and the Western Australian border, spanning 949km within South Australia. It passes through the major towns of Kimba, Wudinna, Minnipa, Ceduna, and Penong before reaching Border Village and is an arterial route that connects Western Australia to South Australia and the east coast. The highway was analysed in RAA s Backwater to Benchmark in 2005 and was re-assessed for Towards 2020 in At the time of Towards 2020, the highway carried between 380 and 775 vehicles per day, 40% of which were commercial vehicles. Of this commercial traffic, 60% of the traffic consisted of B-double, double and triple road trains. As of June 2014, traffic studies have shown the traffic volumes range between 480 and 2,700 vehicles per day equating to a 61% increase in traffic over five years. Over the past 5 years, there has been an average of 59 crashes per year with the majority of incidents involving run-off road crashes that have resulted in hitting fixed objects or vehicle rollovers. The highest numbers of crashes occur on the section between Port Augusta and Iron Knob. According to crash costs estimates derived from BITRE and AusRAP, it is estimated that the cost of crashes on the for the past five years has been $71,387,448. RAA performed an assessment of the in March The assessment identified the need for wider traffic lanes to the west of Penong, a recommendation that has been iterated since Backwater to Benchmark. Sealed shoulders widths were generally found to be 500mm but it would be preferable to increase these to at least 1m. The assessment noted the absence of Audio Tactile Line Marking (ATLM) from the entire highway which was disappointing particularly since lanes are narrow to the west on Penong and ATLM have demonstrable benefits in reducing run-off road crashes. An assessment of the pavement condition was also performed and the pavement was found to offer good ride quality offering a smooth run for motorists. The extent of rutting was however a concern with several areas identified as having below average rut levels which could increase the potential to aquaplane in wet weather, particularly between Yalata and Border Village. The pavement texture was found to be either well textured or coarse, with a few exceptions occurring between Poochera and Ceduna that had a smooth finish, offering less skid resistance. Roadside hazards were identified as an issue. Trees line the highway between Port Augusta and Ceduna however other hazards such as Stobie poles and pipe lines located between 5 8m of a seal were identified as particular issues and could benefit from barrier protection. Steep embankments on straight sections and on the outside of bends were also identified as a major hazard and should also be protected. Asphalt edge drop was identified as a hazard as the difference in level between the sealed pavement and unsealed shoulder could present potential issues for motorists drifting between the seal. This issue is substantially mitigated through the provision of wider sealed shoulders. Road signage along the route was good however some bends did not have warning signs or advisory speed plates when it was felt that it could be of benefit and more advanced warning for turn offs to rest areas and tourist attractions is required in some areas to reflect the high speed environment.

5 Rest areas were found to be regularly spaced but lacked amenities that would encourage motorists to stop, particularly in remote areas and further work is required to upgrade some of the key rest areas. RAA s findings were combined with AusRAP data collected in early 2012 to formulate recommendations for infrastructure investments to improve safety and the driving experience. These recommendations include: Apply pavement re-surfacing (Minimum 53 Km); o From Port Augusta, westwards for a distance of up to 10Km; o Between the eastern boundary of Lake Gilles Conservation Park and Yaninee, with particular attention to the section that runs through Lakes Gilles Conservation Park and the section between Wudinna and Yaninee; and o From Yalata, eastwards for a distance of up to 24 Km. Apply ATLM (Minimum 63 Km); o From Port Augusta, westwards for a distance of up to 8 Km; o From the intersection with Lincoln Highway, westwards for a distance of up to 9 Km; o Between the eastern boundary of Lake Gilles Conservation Park and Cungena; o From Penong, westwards for a distance of up to 18 Km; o 10Km east of Yalata, eastwards for a distance of up to 8 Km. Installation of roadside barriers (Minimum 12 Km); o Between Port Augusta to a point 10 Km west of the intersection with Lincoln Highway, to protect road users from Stobie Poles. Increase lane and shoulder widths to 3.5m and minimum 500mm respectively between Penong and Border Village; Provide rut filling / resurfacing at the poorest performing locations; Implement a shoulder remediation program to address edge drop; Provide community safety group funding to maintain signs; Complete a sign review on sections with multiple bends; Install further tourist direction / information signage further from the turns or consider installing deceleration lanes; and Upgrade key rest areas to at least provide sheltered seating, bins and LED lighting. 2

6 Table 1 shows the results of the 2012 AusRAP star rating for the and compares this to the star rating that could be achieved if all of the above recommendations are followed. Star Rating 2012 Length (%) Post Investment Plan Change Table 1 - AusRAP Star Rating Pre & Post Investment Plan It should be noted that the contents of this report are solely based on the 2012 AusRAP assessment and RAA s 2013 assessment. The report does not therefore reflect any maintenance or upgrade programs that the Department for Planning, Transport and Infrastructure (DPTI) may have undertaken between 2013 and

7 1 Traffic Volumes The runs between Port Augusta and the Western Australian border, spanning 949km within South Australia. It passes through the major towns of Kimba, Wudinna, Minnipa, Ceduna, and Penong before reaching Border Village and is an arterial route that connects Western Australia to South Australia and the east coast. The highway was analysed in RAA s Backwater to Benchmark in 2005 and was re-assessed for Towards 2020 in Being the only direct link between South Australia and Western Australia, the Highway carries high volumes of tourist traffic as well as commercial vehicles. Despite this, the total daily volumes of traffic remain low in comparison to other rural highways in the state. At the time of Towards 2020, the highway carried between 380 and 775 vehicles per day, 40% of which were commercial vehicles. Of this commercial traffic, 60% of the traffic consisted of B-double, double and triple road trains. As of June 2014, traffic studies have shown the traffic volumes range between 480 and 2,700 vehicles per day equating to a 61% increase in traffic over five years. Heavy goods vehicles account for approximately 25% of the total traffic flow. The shift in the balance of light and heavy vehicles could be attributed to expansion of towns along the route as well as indicating a strong increase in tourist traffic travelling between South and Western Australia. During the 2013 highway assessment, RAA observed high volumes of vehicles towing caravans, which reaffirms that the is growing in popularity among tourists. Although the ratio of HGVs to light vehicles has decreased in the last 5 years, the highway assessment also identified that many double and triple road trains use the route. It is anticipated that the volume of such vehicles will increase along with the future mining expansion in the region. The high proportion of HGVs using the is an issue since the lane widths in some areas are narrow and there are presently no overtaking lanes along the highway. As traffic volumes increase, measures such as these will certainly be required. 4

8 2 Crash Statistics The crash statistics over the last 5 years have remained consistent, with an average of 59.4 crashes per year. In 2009, the lowest numbers of crashes were recorded on the with only 53 crashes, however in 2010, 66 crashes were recorded. Run off road incidents that resulted in roll overs or hitting fixed objects are the most frequent types of collision but hit animal collisions are also quite common. Roll over crashes result in the most fatalities and have accounted for 5 of the 7 fatal crashes in the past 5 years. Hit fixed object accounts for the remaining 2 fatal crashes in the past 5 years Figure 1 - Crashes on, The majority of crashes along the tend to involve property damage only. During the five year monitoring period there have been 181 property damage only crashes, 59 minor injury crashes, 50 serious injury crashes and 7 fatal crashes. 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Property Damage Only Minor Injury Serious Injury Fatal Figure 2 Crashes by Severity,

9 Number of Crash Severity Cost per Total Cost Crash 1 crashes (2013 Values) Property Damage Only $12, $2,225,735 Minor Injury $17, $1,081,713 Serious Injury $340, $17,680,000 Fatal $7,200,000 7 $50,400,000 Table 2 - Cost of Crashes on (2013 Values), The estimated cost of crashes along the between 2009 and 2013 is $71,387,448. This figure includes losses to workplace and households as well as a number of medical, insurance, accident investigation, legal and repair costs. The above table breaks down the cost of crashes by severity for the past five years and highlights that each fatality costs over $7M, which in turn is just over 21 times higher than the cost of a serious injury. Therefore any change in the number of fatalities would have a significant impact on the overall cost for a particular road or area. Figure 3 illustrates the number of crashes by location along the by section for the five year period, 2009 to Crash totals tend to vary along different sections of the, with crashes occurring more often per kilometre between Port Augusta and Iron Knob. 1 Property damage only and minor injury costs derived from Cost of Crashes in Australia 2006, BITRE Research Report 118; Figures amended to reflect 2013 values. Serious jury and fatal costs derived from AusRAP 2013 Star Rating Australia s National Roads. Note that the costs displayed are for each crash type and not for each casualty. 6

10 Figure 3 Crashes Along,

11 3 Highway Geometry The passes through a diverse environment that influences the geometry from region to region. Typically, between Port Augusta and Ceduna, the highway is characterised with some long sections but straights are typically shorter with a series of bends connecting these sections. Significant trees and dense vegetation are found on both sides of the highway through this region. Past Ceduna, the opens up on the Nullarbor with long straight sections for several kilometres as it passes over the plains with low lying scrub and grasses. 3.1 Lane Widths In Towards 2020, RAA recommended that the seal width between Ceduna and the SA/WA border be increased. This was following on from previous recommendations made in 2005 and again 2006 which called for minimum lane widths of 3.5m to the west of Ceduna. Lane widths were further highlighted as a concern in the Adelaide-Perth corridor strategy released in 2007, which recognised the corridor s importance in supporting the freight industry. RAA s 2013 assessment found that lane widths varied between 3.0 and 3.6m. For most of the highway, the lane widths averaged at approximately 3.5m but west of Penong, this dropped to approximately 3.0m. Just prior to the Nullarbor, the lane widths increased slightly and averaged 3.2m per lane which continued through to the border. Upon crossing the border, there was a noticeable increase in lane and shoulder widths on the section maintained by Western Australia. Research has shown that to comfortably accommodate a B-double or B-triple road trains along a straight section of road, a lane width of 3.5m is required. This allows for lateral movement in the trailer tracks and provides an element of safety in the event of sudden wind gusts which may displace the trailer. When taking bends into account, 3.6m and above would be preferable. The section of the west of Penong should therefore be considered for future lane extension work with priority assigned to the section across the Nullarbor since the environment can foster strong crosswinds. 3.2 Sealed Shoulders The provision of shoulder seals is necessary to allow the driver to correct their course should they drift from the traffic lane. At a minimum, a 500mm shoulder seal should be provided however it is preferable to include 1m to 1.2m seals where there is a high risk of vehicles departing the road such as on bends or on straight sections within high fatigue zones. The assessment found that where lane widths of 3.5m were recorded, shoulder seals of 500mm were generally provided although on some sections of road, the seal was found to be 600mm. The shoulder seal was found to reduce to between 300mm and 400mm to the west of Penong. Between Nundroo and Nullarbor, the shoulder seals varied between sections. At a few locations, an extra wide seal of between 900mm and 1200mm was provided however there were also a number of locations at which a 200mm seal was provided, which would offer limited protection if a vehicle was to drift from the traffic lane.

12 Narrower seals can be provided if other countermeasures such as Audio Tactile Line Marking (ATLM) are present however in addition to lane widening, shoulder sealing should be considered a priority on the, particularly on the western section after Nundroo. 3.3 Audio Tactile Line Markings Audio-Tactile Line Marking (ATLM) is a series of raised bars positioned on the edge lines of the highway, 50mm wide, 150mm long and at 200mm spacing along the edge line. Currently, the Department of Planning, Transport, and Infrastructure (DPTI) use Thermoplastic Rib Profile ATLM on South Australian highways. ATLM reduce crashes due to driver fatigue by alerting the driver when they begin to move out of the driving lane. When a wheel passes over the ATLM, the ribs cause a noise and vibration which is felt by the driver and alerting them to take corrective action. ATLM also helps to highlight delineation in wet or low visibility situations, such as heavy rain or fog. The 2013 assessment of the noted an absence of ATLM for the entirety of the highway. It is the Department of Planning, Transport and Infrastructure s (DPTI) policy to install ATLM on arterial routes that demonstrate a high number of instances of fatigue crash types (Clark, 2009). It is often difficult however to quantify if a run-off road crash was fatigue related unless it occurred early in the morning or late at night. It is highly recommended that ATLM is included in the s investment plan since the many of the run-off road crashes are likely to be fatigue related but ATLM also serves to protect drivers from run-off crashes due to inattention. Priority should be given to introducing ATLM on sections that include a series of bends, sections with notably narrow lane and sealed shoulder widths and sections that have a crash history which include fatigue or inattention. 4 Pavement Performance 4.1 Ride Quality RAA s 2013 assessment determined that the highway had a smooth ride quality throughout with very few bumps and undulations which provided a comfortable drive. As part of the assessment, RAA engaged a pavement survey to be undertaken, the results of which are shown in Figure 4 below. The pavement testing utilises a laser measurement device and the results are recorded in terms of the International Roughness Index (IRI). The lower the IRI, the smoother and more comfortable the ride experience is for the motorist. The map shows that throughout the highway, the ride quality is good (IRI less than 1.94), offering a smooth ride with few undulations. Between Port Augusta and Poochera, there are many sections that the IRI was recorded between 1.94 and 2.68 but this is still considered average and will offer a comfortable journey to the road user. There were very few sections that offered an acceptable or below average ride quality which is very encouraging to note for such a rural highway. 9

13 It is expected that any minor issues associated in ride quality, most of which occur between Kimba and Poochera can be addressed as part of ongoing maintenance however this is not a high priority as other safety infrastructure is required along the route. 10

14 Figure 4 Ride Quality Map for

15 4.2 Rutting The 2013 highway assessment identified rutting in a number of locations, particularly between Yalata and Border Village. The ruts were more noticeable during the wet spells throughout the week, as water often ponded in the ruts. Rutting is particularly dangerous for this reason as aquaplaning may occur if the water is of sufficient depth. The pavement assessment found that rutting is a wide spread problem throughout the (Figure 5). The main issues occur prior to Kimba, around Wudinna, Yalata and Border Village. At these sections the rutting is below average (10 15mm deep) or poor (above 15mm deep). After Yalata and also prior to Border Village, the majority of the ruts were greater than 15mm. This is disappointing as any ruts greater than 10mm has the potential to trap sufficient water to cause aquaplaning. In addition to aquaplaning, ruts can also affect the tracking of trailers behind vehicles by acting as guide rails for the wheels. There were limited sections which demonstrated good or acceptable levels of rutting (less than 5mm), most notably between Port Augusta and Iron Knob. In addition to rutting, it is worth noting that where the lane or shoulder seal has been extended, the asphalt has followed the level of the road base which has created a V channel at the join. This has created an artificial rut and in many locations, water was noted flowing down the joint or ponding in the depressions. It is recommended that rut filling and re-surfacing is undertaken at the priority areas to improve driving conditions in wet weather. Future care should also be taken when extending seals to ensure that the extension drains well. 12

16 Figure 5 Rutting Map for Dukes Highway

17 4.3 Texture In the 2013 highway assessment, there were few issues that RAA observed in the pavement texture. Between Poochera and Ceduna, some sections of road suffered from bitumen bleeding whereby the surface aggregate is pushed into the bitumen binder by the weight of vehicles, causing the bitumen to rise to the surface. This creates a smooth and polished looking surface which can reduce the skid resistance. The pavement assessment included an examination of the texture using a laser measurement device; the results of which are shown in Figure 6. The results show that the pavement is well textured between Port Augusta and Poochera, offering sufficient skid resistance. With a few exceptions, the pavement has a course texture between Ceduna and Border Village which offers good skid resistance. Areas of concern are between Poochera and Ceduna and a section approximately half way between Yalata and Border Village. There the texture was found to be smooth, offering poor skid resistance. At one location, the texture was less than 0.7mm which is considered flush and should be addressed as a matter of priority. The poor texture that was identified by AusRAP confirmed the instances of bitumen bleeding observed by RAA. The volumes of HGVs along this section of the highway is the same or lower than other sections, suggesting that it is not heavy traffic along that is leading to deterioration. The bitumen bleeding can be caused by a number of factors but is often attributed to excess binder when laying the surfacing or laying the surface in hot weather. If these sections of the highway are seasonally subjected to hotter temperatures than others then gradually over time, traffic will press the aggregate into the binder when soft, leading to the bleeding effect. The loss of texture may be rectified using a mechanical method to create a new texture in the existing surface or alternatively a further spray seal with chip coating will improve the skid resistance. 14

18 Figure 6 Texture Map for Dukes Highway

19 5 Roadside Hazards 5.1 Roadside Objects & General Hazards The passes through a diverse landscape that can be broadly classified in two categories. Prior to Ceduna, the highway is generally lined with trees and dense vegetation and poses a risk of hitting fixed objects for vehicles that run off the road. After Ceduna, as the highway passes over the Nullarbor, the landscape opens into mostly low lying vegetation which does not pose a threat for vehicles that depart the highway however there is increased risk on this section of over correction, leading to a vehicle roll-over. The highway assessment noted that in many areas prior to Ceduna, significant vegetation grows within 5 8m of the seal. A clear zone of 10m from the edge of the seal is preferred although studies have shown that vehicles departing the highway can travel much further than this. Clearly it would not be possible to provide this level of clear zone for the entirety of the highway, both from a program funding and an environmental point of view but extension of the clear zone or barrier protection should be considered in high risk areas that have an accident history. There were a number of occasions that Stobie poles were noted within 5 8m of the carriageway and on one occasion, approximately 2m from the seal. It is preferable to protect poles located less than 10m from the seal with W-beam barrier but when poles are located 2m or less from the seal; they should be protected with a barrier and at the bare minimum have a black and white reflective hazard board erected on the side of the pole. On occasions, RAA noted culvert headwalls at the edge of the highway that were unprotected. Protection should be offered to such infrastructure as headwalls can act as snagging points for vehicles that depart the seal and may cause vehicles to rollover when passing over the edge of the headwall. RAA were surprised to find that a major supply pipeline runs beside the unprotected at a number of locations. The 800mm diameter pipe appears to pump water from the Tod Reservoir on the Eyre Peninsula to towns along the route. RAA found that the pipe encroached on the highway, 5 to 8m from the seal at a number of locations. It is strongly recommended that the pipeline is protected at these locations. If a vehicle were to depart the highway, collision of the pipe line would result in a high severity crash and potentially lead to an extended interruption of the supply. The cost of a barrier treatment should be weighed against the economic costs of repair of the pipeline and loss of service would likely be substantial. 5.2 Embankments Embankments present a major roadside hazard since particularly steep embankments often cause run-off road vehicles to roll, escalating the severity of the crash. The highway assessment identified numerous embankments falling away from the highway, many of which were steep and unprotected. Of the 17 locations identified as a 16

20 concern, three of the locations had embankment heights of around 5 8m, were located on bends and were protected with roadside barrier. There were another two sites that had approximate falls of 5 8m that were unprotected and the remainder of the sites varied up to 5m in height and were left unprotected. Approximately one third of the unprotected sites were on bends. RAA are disappointed with these findings since embankments greater than a couple of metres high can hide a run-off road vehicle from sight so it may take longer for a passing vehicle to find them, which may significantly change the outcome of a crash. It is recommended that further assessment is undertaken to identify locations for barrier installation that will protect significant drops on both bends and straight sections of the highway. 5.3 Edge Drop An emerging issue identified during the assessment was the level difference between the sealed pavement and the unsealed shoulder which created an edge drop from the traffic lane. This was particularly noticeable between Nundroo and Nullarbor where drops of between 50 and 80mm were recorded. Figure 7 shows the extent of the edge drop at one of the locations that were examined. 60mm Figure 7 - Edge Drop Edge drop is a potentially serious issue since deep drops may prevent a driver recovering onto the seal if they drift onto the shoulder. The drop may suddenly pull vehicles off the seal if drivers become too close to the edge and the sudden response from the motorists may result in over correction leading to loss of control and roll over. Additionally if the drop is deep ad a driver attempts to pull a vehicle back onto the seal, the edge of the asphalt contacts the side of the tyre and the rough surface could potentially lead to a blowout, again with serious consequences. Truck drivers 17

21 commented that when driving their trucks, and particularly in the case of road trains, the drop makes it extremely difficult to pull the trailers back onto the seal. The most desirable solution to the issue is to level and seal the shoulders to a minimum of 1.0 to 1.5m as this will also address issues with asphalt breaking away at the edge of the seal. In recognition of the high costs of this treatment and the time required to apply shoulder sealing across the highway, it is recommended that a more frequent shoulder maintenance program is followed to maintain high quality unsealed shoulders. Increasing the level of the shoulder to meet the edge of the asphalt and suitable compaction should reduce shoulder rutting and the instances of edge drop. 6 Safety Barriers RAA noted the presence of safety barriers at discrete locations. Some barrier protection has been provided on bends that have a significant drop to the side of the road however barrier protection has primarily been provided on approach to bridges or culverts. According to AusRAP, a total of 12.8 km of the has been provided with safety barriers. RAA are concerned about a number of embankments along the route, particularly on bends. There are also a number of fixed road side objects such as Stobie Poles that require protection and protection should be offered from significant vegetation at least on the outside of bends. Further funding is desperately needed for the Eyre Highway to enable a barrier installation program that will target locations that have a high risk of run-off road crashes. 7 Signs & Line Marking The assessment determined that the condition of the line marking throughout the Eyre Highway was generally good or at least adequate. The exception was the intersection with the Lincoln Highway where the line marking was found to be fading and could benefit from refreshing. It is likely that this has already been done since the assessment was originally undertaken. There was a good standard of signage along the highway. RAA noted a number of community safety group signs throughout the journey, some of which had become faded or vandalised. The signs promote good driving practice such as turning headlights on during daytime when travelling along the straights to make vehicles more conspicuous. Road safety groups in the region should be encouraged to apply for modest funding to allow these signs to be maintained. Approximately 5km prior to Iron Knob, the assessment team reported a near collision with an Emu. The conditions were wet and overcast and it was difficult to distinguish the birds from the surrounding scrub. Emu warning signs are provided in Iron Knob itself but consideration should be given to providing signs on this section of the if Emus regularly reside within the area since they are likely to be unexpected by non-local traffic. The assessment noted a number of locations, most notably prior to Iron Knob, after Kimba and between Poochera and Wirrulla that had a sharp bend or series of bends that could benefit from advance warning signs and where appropriate, advisory speed plates. 18

22 Across the Nullarbor, some signs appeared to have been vandalised and on one occasion a sign was missing for an emergency phone. It is recommended that a sign review is undertaken as part of ongoing maintenance to address these deficiencies. As the approaches the coast, there are a number of rest stops, viewpoints and tourist attractions such as the Head of Bight. The assessment found that the advanced directional and information signs for many of these stops was perhaps not located far enough from the turn considering the 110km/h speed limit. Many of the turns did not have protected turn lanes and given the composition of Caravan and HGV traffic on the route, it is felt that further notice should be given to allow motorists to safely slow to make the turn. This could be achieved through the use of repeater signs. 8 Rest Areas Good quality rest areas are important in preventing driver fatigue since they encourage drivers to stop and take a break more frequently. Towards 2020 called for upgrades of key rest areas, to provide a high standard of amenities such as toilet facilities, solar lighting and sheltered tables and chairs. The 2013 assessment recorded approximately 34 rest areas throughout the journey. This excludes any rest areas provided in and around townships and equates to a rest area approximately every 27km. While it is encouraging to find that frequent rest areas have been provided the quality of rest areas significantly vary. Most rest areas are basic, with an unsealed layby with litter bins provided. Some have tables and seating while few offer shelters. None of the rest areas appeared to have lighting or toilet facilities provided except those at tourist attractions such as Head of Bight. Funding is required to upgrade strategic rest areas. Shelter should be provided and in remote locations solar LED lighting would be beneficial to make motorists feel safe stopping at night. Many of the rest areas should also be sealed to enable all weather access for trucks (at truck stops) or vehicles towing trailers and caravans. 9 AusRAP Although AusRAP rated 32% of the highway as having adequate skid resistance, there were issues identified with 60% rated as medium and 8% as poor. Additionally, AusRAP confirmed the absence of ATLM noting that the lines had not been used on any section of the highway. There has only been approximately 12.1km (2%) of W-beam barrier p and 700m of wire rope barrier provided to protect roadside hazards and most of the highway remains unprotected. 19

23 Table 3 summarises the unprotected road side hazards that were identified: Hazard Km % Upwards Slope (Rollover Risk) Downwards Slope Tree (Trunk >= 10cm Diameter) Sign, Post or Pole (>= 10cm Diameter) Drainage Ditch Large Boulders >=20cm Table 3 Key Hazards Identified by AusRAP The star ratings calculated from the AusRAP analysis are shown in Table 4 below. It should be noted that the rating fell in 2013 as a result of a revised version of the Star Rating system, that applied more stringent assessment criteria in the rating calculations. Length (%) Star Rating Table 4 - AusRAP Star Rating The AusRAP program calculates a series of countermeasures, based on the star ratings. The key recommendations are: Resurfacing to improve skid resistance (53.4 Km) Provision of Audio Tactile Line Marking (62.5 Km) Installation of road side barrier (12.3 Km) A detailed schedule of countermeasures is included in Appendix B. Table 5 below shows a comparison of the current star rating to the potential star rating awarded to Eyre Highway if all the proposed countermeasures are implemented. Star Rating 2012 Length (%) Post Investment Plan Change Table 5 - AusRAP Star Rating Pre & Post Investment Plan 20

24 10 Summary & Recommendations The was reviewed in Backwater to Benchmark in 2005 and Towards 2020 in Since then, there has been some improvements made to the highway but not to the extent that RAA desired, which has left many of the original recommendations still valid. Central to these recommendations is the 61% increase in traffic in the last 5 years. This is likely to increase over the next 5 years with further expansion of the mining sector within the region and provides financial justification for improving the quality of the highway. RAA assessed the highway in 2013 and combined the findings of the assessment with the output from the AusRAP program to provide a series of recommendations to improve safety and driving experience. The recommendations, which have been assigned no order of priority, are: Apply pavement re-surfacing (53 Km); o From Port Augusta, westwards for a distance of up to 10Km; o Between the eastern boundary of Lake Gilles Conservation Park and Yaninee, with particular attention to the section that runs through Lakes Gilles Conservation Park and the section between Wudinna and Yaninee; and o From Yalata, eastwards for a distance of up to 24 Km. Apply ATLM (Minimum 63 Km); o From Port Augusta, westwards for a distance of up to 8 Km; o From the intersection with Lincoln Highway, westwards for a distance of up to 9 Km; o Between the eastern boundary of Lake Gilles Conservation Park and Cungena; o From Penong, westwards for a distance of up to 18 Km; o 10Km east of Yalata, eastwards for a distance of up to 8 Km. Installation of roadside barriers (Minimum 12 Km); o Between Port Augusta to a point 10 Km west of the intersection with Lincoln Highway, to protect road users from Stobie Poles. Increase lane and shoulder widths to 3.5m and minimum 500mm respectively between Penong and Border Village; Provide rut filling / resurfacing at the poorest performing locations; Implement a shoulder remediation program to address edge drop; Provide community safety group funding to maintain signs; Complete a sign review on sections with multiple bends; 21

25 Install further tourist direction / information signage further from the turns or consider installing deceleration lanes; and Upgrade key rest areas to at least provide sheltered seating, bins and LED lighting. These recommendations would result in a notable improvement in sections from 1-star to 2-stars as well as creating further 4-star sections. 22

26 11 References Clark, S 2009, Audio-Tactile Line Marking, Department of Planning, Transport and Infrastructure (DPTI), Government of South Australia, Adelaide. Principal Road Designer 2002, Guide to the Selection of Safety Barriers GD100, Department of Planning, Transport and Infrastructure (DPTI), Government of South Australia, Adelaide. 23

27 Appendix A Pavement Performance Factors 24

28 Overview of Pavement Properties Roughness The pavement roughness refers to the irregularities in the road s surface in the direction of travel. These irregularities vary from 0.5m to 50m long and are measured in relation to the intended road surface and recorded in terms of the International Roughness Index (IRI). As the IRI increases, it indicates a rougher pavement surface which will produce an uncomfortable ride for the vehicle s occupants through bumps and undulations. Figure 1 shows the longitudinal profile of a road with an exaggerated surface. The red line indicated the intended surface level and the difference between the lines is the measured roughness. The roughness is not only important for the ride quality experienced by the motorist but prolonged vehicle exposure to a rough road may also increase wear, maintenance and fuel consumption. Figure 1 Longitudinal Road Section 25

29 Rutting A rut is a defect in the form of a longitudinal depression in the pavement surface. It usually occurs in the wheel path of vehicles (Figure 2) and is caused by high volumes of heavy vehicles over time. Ruts can also form as a result of environmental influences such as extensive rainfall combined with a poorly sealed surface. This can permit moisture to enter the pavement foundations which can weaken the structure or cause movement in the soil beneath, both of which can lead to rutting. X X Pavement Section X - X Figure 2 Pavement Rutting While rutting can lead to further pavement deterioration, several other problems may also arise as a result. Deep ruts can cause a guide channel for wheels and drivers may experience reduced steering performance or having difficulty with trailers tracking the vehicle. Ruts are also prone to filling with water which can increase the potential for aquaplaning, depending on the vehicle speed and depth of the rut. Drivers should always exercise caution when driving in wet weather but particularly on roads that are prone to bad rutting. 26

30 Texture The pavement texture is important to ensure safety for motorists as it provides friction between the contact area of the tyre and the pavement surface. If there is insufficient friction between the tyre and surface the braking distance will be significantly reduced and if the vehicle speed is too high, there may be a loss of control on curves and bends resulting in collisions with roadside objects. There are two forms of texture within the road surface, the microtexture and macrotexture. The microtexture is created by the rough surface of the aggregate in the surface the road and contributes to the friction that ensures the vehicle maintains contact with the road and provides good braking performance. The macrotexture is formed from the grooves created in the road surface by the different heights and shape of the aggregate and is important to ensure that rainwater drains away from the tyre, reducing the potential for aquaplaning. 0mm 0.5mm 0.5mm 50mm Microtexture Macrotexture Bitumen Aggregate Figure 3 Pavement Texture 27

31 Appendix B AusRAP Safer Roads Investment Plan 28

32 Dukes Highway Safer Roads Investment Plan Total FSIs Saved Program BCR Countermeasure Length / Sites FSIs saved Program BCR Sight distance (obstruction removal) 0.30 km Protected turn lane (unsignalised 4 leg) 4 sites Clear roadside hazards - driver side 4.20 km Clear roadside hazards - passenger km Shoulder sealing driver side (>1m) 3.00 km Roadside barriers - driver side km Skid Resistance (paved road) 2.40 km Protected turn lane (unsignalised 3 leg) 15 sites Roadside barriers - passenger side km Shoulder rumble strips km Shoulder sealing passenger side (>1m) 2.50 km Total