Asset Management

Acceptable footpath gradient and driveway crossfall

  • 1.  Acceptable footpath gradient and driveway crossfall

    Posted 01 July 2019 21:57
    Hi all,

    Most of the established urban areas in the City of Glenorchy are situated at steep terrain and have footpath and driveways constructed in the past, which are not meeting the current standard/guidelines (e.g. max 2% in the Australian Standard, and max 4% in the IPWEA standard drawing for footpaths).

    Lots of design efforts were put in aiming to bring these assets to the current standard as close as possible when they were due for renewal. Council from time to time had to accept 6-11% crossfall for footpaths after explored all the possible options. The options generally ended up with lifting road, changing road to one-way crossfall, constructing retaining walls, chasing the gradient into property boundary, and reconstruct private driveways.

    These extra works significantly increased the cost of assets renewal. Looking the issue from an asset management perspecitive, we came to the conclusion that the Council cannot afford such high level of service (do the best we can). The actual renewal cost ($/m) could be three to four times higher than the rates used for asset valuation, developing LTFP, and setting Council rates. We realised that such 'upgrade' works are financially unsustainable and need to change the current practice.

    Wondering has anyone had experience in terms of setting standards, guideline or process on making these engineering judgement calls that when and where the non-standard footpath and driveway can be accepted? We are developing the footpath hierocracy (not necessarily in line with the road hierocracy) and keen to have different Level of Service assigned to them from both maintenance and renewal perspective.

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    Frank Chen
    Manager Infrastructure, Engineering and Design
    Glenorchy City Council
    fchen@gcc.tas.gov.au 03 6216 6342
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  • 2.  RE: Acceptable footpath gradient and driveway crossfall

    Posted 02 July 2019 22:21
    Hi there

    Please refer to the NZTA pedestrian Network Guide or Austroads.

    2-4 % crossfall is essential as people on mobility scotters can tip over and get injured.

    ​https://www.nzta.govt.nz/resources/pedestrian-planning-guide/design-pedestrian-network/
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  • 3.  RE: Acceptable footpath gradient and driveway crossfall

    Posted 03 July 2019 20:30
    I agree that that is ideal, but in reality, no Council can afford to rebuild every path to match these criteria. I've had similar discussions around all accessible toilets, where a consultant wanted us to move a pan 50mm in a 60 y.o. facility to meet the current standard. That's just not going to happen.

    You need to think about what the community needs. Identify what paths are critical and have high mobility scooter use, and put those on a replacement program. In the short term prepare a map that has paths colour coded - green safe, yellow, take care, red not recommended. Give them to the local hospital, doctors, Senior Citizens groups, etc. You could also paint the colour at the start of each path or change of grade to help identify problem areas.

    Education is also a big thing, but that's hard work. A lot of scooter drivers seem to have a "she'll be right" attitude, and assume everyone else will look out for them.

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    Ricky Luke
    Asset Management Coordinator
    Glenelg Shire Council
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  • 4.  RE: Acceptable footpath gradient and driveway crossfall

    Posted 04 July 2019 22:55
    ​Whilst we all strive to meet the max 2.5% crossfall for footpaths the reality is that in certain areas it is never going to be achievable without then compromising residential access to properties. In certain instances the crossfall may be achievable however the longitudinal grade is not. This is a common problem in brownfield developments and while crossfall appears to be adhered to in greenfield developments longitudinal grade is quite often ignored as it would simply make some developments unviable. Some years back I penned a letter to the Human Rights and Equal Opportunities Commission seeking an answer to the reasoning behind the 2.5% crossfall requirement when wheelchairs could obviously traverse 4% and more and 2.5% was just not achievable in some areas. I asked if there was any flexability in the standard. There was no response and I suppose that sums up the situation in a nutshell. There will be some areas where the standard simply can not be applied no mater how much money you can put towards it and the unfortunate reality is that there will remain some areas that will simply not ever be accessible to those people who rely upon mobility aids.
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  • 5.  RE: Acceptable footpath gradient and driveway crossfall

    Posted 10 July 2019 17:37
    Hi all,

    Thank you for these who responded my initial enquiry and shard their thoughts.

    It appears the current standards and guidelines in both Australia and New Zealand are quite similar, where the gradients for footpath and driveway crossover are generally being no more than 4%.

    In my view, having such a high level of service for the communities who are living in established urban areas on steep hills, it is neither the Level of Service they are paying for now nor something they cannot afford in the future.

    The rates the community is paying for generally are calculated based on a number of financial parameters, including the annual depreciation and the annual capital renewal demand. I would not be surprised to see a gap between the total asset replacement value on the book (defining annual depreciation) and the actual total renewal cost after adding cut/fill, building new retaining walls, rebuilding private driveways.

    Now the question is quite simple, either increasing the rate or dropping the LoS (removing existing aged footpaths which are not in the CBD area and do not comply - social equality?).

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    Frank Chen
    Manager Infrastructure, Engineering and Design
    Glenorchy City Council, TAS
    fchen@gcc.tas.gov.au 03 6216 6342
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  • 6.  RE: Acceptable footpath gradient and driveway crossfall

    Posted 11 July 2019 23:07
    If we think seriously about this issue, we are balancing the scales between fiscal responsibility and providing levels of service that are practically used by those who are not as flexible or dexterous as those who enjoy a younger age.  With an aging population and legislation being introduced to provide consideration for those who may have some form of physical or other disability, the issues Frank raises are realistic.
    With the topographical territory in many SE Tasmanian councils, the question is do we adhere to standards (and consider those less fortunate) or do we "look outside the square" as we need to do as engineers and develop innovative ideas.  With the steep slopes on verges/footpaths, and the type of grass cover why is not just steepening the slope of the balance of the verge/footpath a rational idea?  Achieving gradients on driveways for motorized vehicles and space inside a property is more easily achievable than regrading roads, installing retaining walls, constructing split carriageways etc..  However, when that is the only achievable practical outcome (and sometimes it possibly is), do we just do what we need to do or do we educate the community to accept a lower level of service?
    From a pragmatic perspective, how much does increasing the slope of the pathway/cycleway/pedestrain way really achieve?  Increasing crossfalls on a 1.5m path achieves ~112mm lift which may not be of much use when retrofitting or redesigning, so why even talk of impacting this zone of the verge.  Let's look for innovative ideas that don't cost the earth.​

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    Alan H Walker
    Senior Stormwater & Waterways Engineer
    Kingborough Council
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  • 7.  RE: Acceptable footpath gradient and driveway crossfall

    Posted 03 July 2019 01:07
    ​Hi Ruofan & Fellow IPQEA Colleagues,

    I have noticed with some concern in recent years that our profession has become more and more codified and there is almost nowhere we can apply our INGENUITY as professionals. We are damned if we apply the standards blindly and damned if we don't. But if we follow standards and codes blindly, we run the risk of reducing ourselves to the status of technicians. Nowhere is this more obvious than in the design standards we currently apply to pedestrian bridges and walkways/cycleways in terms of structural durability and public safety with different components often having greatly varying design lives and standards of service.

    Probably the most important thing I have learned over my long career has been that an engineering solution has to be cost effective and affordable, otherwise it is not a solution. I cannot count the number of designs that have undergone multiple iterations as potential solutions were refined and re-costed. Should I add, it also has to be culturally appropriate and live up to community expectations, most likely measured by the political satisfaction index. If the elected representatives don't like what we suggest, we might be looking for another job. The short answer is, find out what they want, work out what the risks are, uphold the standards where they are appropriate and don't be afraid to go for an alternate more cost effective or innovative approach if they are not.

    When I spent two years in Samoa in the late 90's, we had to re-derive all the road design standards for hilly & mountainous terrain because they had been dropped out of AusRoads and they disappeared from the CAD design templates. That's progress for you. What was appropriate for modern Australia was not appropriate for that location and socio-economic environment. What we ended up with was, I believe, culturally appropriate for the local community. Sure, the design travel speeds did not meet current Australian standards and specifications, but the community could afford them. And just like here, when they can afford a better standard, they can amend them and do it all to a higher standard when the assets come up for renewal.

    Unfortunately we seem to have forgotten that a Desired Standard of Service should be developed in consultation with the community. If they are prepared to accept steeper cross-falls on pavements and paths, write that standard into your asset management plan and that is what you deliver. Take care though, because a steep cross fall on a wet footpath may become a liability -- trips and falls are still the biggest source of claims against LG. Now that I am getting a few more grey hairs (and hopefully becoming a little wiser), I definitely notice that walking on uneven and irregularly profiled pavements is getting harder on my knees and ankles. I have also had to push a wheelchair around on occasions, and even the slightest change in grade, small steps, lips etc, (unnoticeable to younger people), can present a significant mobility challenge for less agile citizens of all ages.

    Finally, may I suggest you take care with this. Organise a disability awareness afternoon for your engineering staff. Hire some mobility aids and set the  team a challenge and try some of these ideas for yourself. Our gold plated standards didn't evolve by accident. It would probably be more appropriate to develop different standards you can apply to different neighbourhood precincts with higher standards around shopping centres, schools and where older residents make up a higher percentage of users. But whatever you do, document everything and every assumption, put it into your formal asset management plan and get Council to endorse the decision.

    Best wishes,
    Allan

    Note: These comments are based on my personal and professional experience providing engineering design and construction services to government and local government for over 45 years. They do not necessarily represent the views of, nor are they endorsed by my current employer.


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    Allan Herring
    CPEng, RPEQ
    Senior Engineer | Design Manager
    CPO Flood Management Team
    Brisbane City Council
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  • 8.  RE: Acceptable footpath gradient and driveway crossfall

    Posted 04 July 2019 17:49
    ​Hello Roufan

    We often have longitudinal grades well over those in AS1428, keeping the path on the grades of the road, so stick to the max 2.5% cross fall for paths, as the prams and wheelchairs have enough to contend with going forward that I don't think they need high crossfalls at the same time.

    On steeper drivewayscrossings, generally we can get them across driveways near the kerb as the grades there to keep water out or stop scraping meets the 2.5%.

    On flatter driveway crossings, the path grade can be met where needed.

    In some areas, the cutting or fill needed to get driveway crossing from the road make getting a path along that side of the road impractical, so scraping is only concern there.

    If the roads are running along the contour, so the longitudinal grade is low, it may be possible to get acceptance of crossfall over the 2.5%

    Good luck


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    Jim Turner | Team Leader, Design & Projects | Ku-ring-gai Council
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  • 9.  RE: Acceptable footpath gradient and driveway crossfall

    Posted 07 July 2019 17:57
    Hi Ruofan,

    I would like to add to the other posts about the issue of the mobility scooter as a new and emerging risk factor for footpaths. I foresee scooters as something that will challenge us all moving forward. Larger crossfalls on footpaths add risk especially to mobile scooter users.

    The use of the mobility scooter is increasing. Of note these scooters are used predominantly by elderly people who have reduced eyesight, co-ordination and proprioception. They do not have the dexterity to respond well to bumps, high grades, suddenly superelevating after driving over a pram ramp wing that is too steep (ie 600mm wide).

    I've had to make changes to a footpath due to an elderly person nearly going over an embankment on one, he was only saved after a tradie stopped his car, got out and pulled the scooter to safety.

    I've personally witnessed an elderly male on a mobility scooter lose control in a camera shop and panic, activating the accelerator and jamming himself into a display apparatus with the accelerator continually on. He was saved by the shop attendant.

    You really cannot have too high crossfalls with these things as the users do not have the ability to cope with any sudden changes or problems, especially if already on a relatively high grade.


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    Matthew Holt
    Construction & Maintenance Engineer
    Northern Beaches Council (NSW)
    t 02 9942 2843 m 0466 926 193

    northernbeaches.nsw.gov.au
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  • 10.  RE: Acceptable footpath gradient and driveway crossfall

    Posted 11 July 2019 23:08
    Hi

    We have drafted a guideline for the design and construction of crossovers - check it out here https://walga.asn.au/getattachment/Policy-Advice-and-Advocacy/Infrastructure/Roads/WALGA-Crossover-Guidelines-rev1-1.pdf.aspx?lang=en-AU

    Mark Bondietti
    Manager Transport and Roads
    WALGA​
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