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Lane width

  • 1.  Lane width

    Posted 02-28-2019 11:40 PM
    Edited by Tirza Austin 02-28-2019 11:40 PM
    I have two issues. 

    1. The lane width for all National Highways in India is 3.5m. The four/six lane divided highways in India have the same configuration. Almost all National Highways have lane marker (central and edge lines). In India the width of edge lines and central lane divider line are different. Do the widths of these lines form part of the bituminous carraigeway width or additional.
    2. The carriageway width in India is 3.5m but in US it is less, though the vehicle width is slightly more. Any specific reason for this?

    Thanks, 

    ------------------------------
    Partha Aich M.ASCE
    Delhi East ND
    9111 42402011
    ------------------------------


  • 2.  RE: Lane width

    Posted 03-02-2019 10:00 PM
    Edited by Tirza Austin 03-02-2019 09:59 PM
    Dear Partha,

    In Canada, lane width is 3.5 m as well. Shoulder width is extra. 
    In my shipping experience, vehicle width is 2.4m (soft conversion from the previous 8 ft. width). That would be the widest object we can normally ship. However if we had to ship wider that that, then there are extra measures such as red flags and possibly police escort in very special situations. The normal width was 2.4 m. The difference of 1.1 m Is for safety.

    In my precast concrete experience, we shipped our product to USA with the same restrictions + height restrictions for passage under bridges.

    Regards,

    ------------------------------
    Neil Kazen, M.Eng., M.Sc., P.Eng.
    FASCE, FCPCI, FEC,
    Retired Structural Engineering Manager, Transportation Division, SNC-Lavalin
    Toronto, Ontario, Canada
    ------------------------------

    Original Message


  • 3.  RE: Lane width

    Posted 03-03-2019 08:21 AM
    Edited by Tirza Austin 03-05-2019 12:50 PM
    Dear Neil,
    The lane width of 3.5m in India is on the same principle. On major National Highways we have paved shoulder of 1.5m also which has the same pavement composition as the main carriageway. The main carriageway and paved shoulder are distinguished by a continuous edge line. Thereafter we have soft shoulder. But as far as I know some countries have cmain carriageway width slightly different.
    The second part is, does the lane marking widths are within the carriageway width or extra? 

    Regards,
    Partha Aich


  • 4.  RE: Lane width

    Posted 03-04-2019 06:58 PM
    Edited by Tirza Austin 03-04-2019 06:58 PM
    Dear Partha,

    Lane lines define only lane widths. Nothing to do with vehicle widths.

    However, on another but related subject, I see at some parking lots, that the lines separating parking spaces are doubled to leave enough space between vehicles.

    ------------------------------
    Neil Kazen, M.Eng., M.Sc., P.Eng.
    FASCE, FCPCI, FEC,
    Retired Structural Engineering Manager, Transportation Division, SNC-Lavalin
    Toronto, Ontario, Canada
    ------------------------------

    Original Message


  • 5.  RE: Lane width

    Posted 03-04-2019 11:25 PM
    Edited by Tirza Austin 03-05-2019 12:50 PM
    Neil,
    Let me put my question in a simple way.
    1. Is lane width of 3.5m is standard all over the world?
    2. Whether the width of edge marking and centre line marking and kerb shyness line (in
    case of divided carriageway with median) are included in the lane width or extra as per
    the standard norms?
    3. As you raised the issue of parking bays, now a clarification is required, whether the
    widths of the bay lines are excluded from the clear width of the parking bays?

    Thanks and Regards,
    Partha



  • 6.  RE: Lane width

    Posted 03-05-2019 08:54 AM
    Edited by Tirza Austin 03-05-2019 09:30 AM
    Partha,

    1- Your question about whether 3.5 m lane width is used worldwide; I don't know.

    2- Given that I'm a Structural Engineer I'm not familiar with some of the terminology you used. Lanes are marked by lines at 3.5 m c/c. Period. 

    3- Parking: as I mentioned, that's in SOME parkings, which implies that it is optional by that specific lot parking owner. It's a good idea. No other comment.

    Regards,

    ------------------------------
    Neil Kazen, M.Eng., M.Sc., P.Eng.
    FASCE, FCPCI, FEC,
    Retired Structural Engineering Manager, Transportation Division, SNC-Lavalin
    Toronto, Ontario, Canada
    ------------------------------

    Original Message


  • 7.  RE: Lane width

    Posted 03-05-2019 11:44 AM
    Edited by Tirza Austin 03-05-2019 11:44 AM
    Partha, 

    1. Is lane width of 3.5m is standard all over the world?

    No. Different jurisdictions have different lane widths, for two reasons. First, the conversion from the original 12 foot width has been rounded in different ways, e.g. 3.7m in Canada, 3.65 in some Latin American countries, 3.6 in others, etc. Second, in Europe and other jurisdictions, the assumption is that there is no need for wide lanes at slow speeds, therefore you might have a range of values, especially for urban facilities e.g. (Canada) 3.7m in freeways, 3.5m in urban roads, 3.3 m for minor streets and 3.0 for turning lanes or minor streets.

    2. Whether the width of edge marking and centre line marking and kerb shyness line (in
    case of divided carriageway with median) are included in the lane width or extra as per
    the standard norms?

    Lane width is constant e.g. if the lane is 3.7m. then the paint stripes are applied 3.7m center to center, and the width of the stripe (narrow stripe, double stripe etc.) varies as necessary

    3. As you raised the issue of parking bays, now a clarification is required, whether the
    widths of the bay lines are excluded from the clear width of the parking bays?

    No, as with the lane widths, the with of the parking stall is constant e.g. 2.4m, and the lines are painted at 2.4m center to center

    ------------------------------
    Sergio Fernandez M.ASCE
    Calgary, Alberta,Canada

    ------------------------------

    Original Message


  • 8.  RE: Lane width

    Posted 03-06-2019 07:52 AM
    Edited by Tirza Austin 03-06-2019 07:53 AM
    Hi Sergio,
    Very well explained. In fact, we have uniform lane width of 3.5m for all National Highways, State Highways and
    Major Roads, which are generally two lane. For four lane/six lane, eight lane divided
    carriageway there is an additional width of 0.3 to 0.5m as kerb shyness. Excepting cases
    of a few expressways, the lane width is measured centre to centre. Nothing extra for
    width of lines. The same applies for parking bays, but the width of bays are different
    for cars and buses.
    In India there is a variation of width for single lane roads. These generally carry low
    volume traffic and falls in category of district roads. Here we have lane width varying
    from 3.0m to 4.0 depending on several factors, like wide shoulder, amount of motorized
    traffic, economics, sustainability, etc.

    Regards,
    Partha



  • 9.  RE: Lane width

    Posted 03-06-2019 09:53 AM
    Edited by Tirza Austin 03-06-2019 09:52 AM
    The U.S. standard recommended lane width for city arterial street is 12 ft, or 3.66 m. I believe the "Green Book" calls for 14 ft. min. for Interstate Highways.
    Gutters are for water to run in, plus drivers shy away from curbs, so curb sections should not be included with the lane width.
    (In my hometown, they did count it face to face of curbs and called for only 35 ft. for one direction of a six lane roadway, marking the asphalt with 11' - 10' - 11' lanes. These older arterial streets are uncomfortably narrow under today's traffic.)

    Parking lots come under architectural standards, which call for 8' (2.44 m.) min stall widths. This leads to unhappiness over dinged car doors and difficulty in getting out of and into cars, so the better practice is 9 ft. min. (mark "Small Cars"?) and 10 ft. where practicable.

    ------------------------------
    Hans H. Coucheron-Aamot
    [Retired]
    Albuquerque NM
    (505) 897-2554
    ------------------------------

    Original Message


  • 10.  RE: Lane width

    Posted 03-07-2019 06:44 AM
    Edited by Tirza Austin 03-07-2019 06:43 AM
    Lane width well explained. Regarding lane width in parking lots, some more clarity is required. Due to increased length and width of modern vehicles with side mirrors, and requirement of larger turning radius to enter and exit the parking bay, my feeling is that the lane width should be standardized to a slightly higher width.

    ------------------------------
    Partha Aich M.ASCE
    Delhi East ND
    9111 42402011
    ------------------------------

    Original Message


  • 11.  RE: Lane width

    Posted 03-07-2019 07:00 PM
    Edited by Tirza Austin 03-07-2019 07:00 PM
    In the U.S., lane widths can vary from 9' (2.7m) to a maximum lane width of 12' (3.6m) on freeways.  The width used depends on several factors including available space, speed, ADT, etc.  Striping is typically 4 inches (10cm) wide but 6 or 8 inch (15-20cm) striping can also be used where conditions warrant (such as areas with high fog or poor visibility).  Crash Modification Factors (CMF) have been useful in making decisions to reduce or increase lane width by studying the effect that changing the lane width has on the frequency of crashes.  Here is a link to one of the studies that was used to generate CMFs for changing lane width:

    http://cmfclearinghouse.org/study_detail.cfm?stid=464

    The one study showed that increasing lane width from 11' to 12' resulted in a 12% reduction in crashes, or a CMF of 0.88.  CMFs can be used and combined to justify whether making a change is warranted in terms of costs and benefits.

    When designing lanes and striping, I typically put the edge of the striping on center between two lanes or, if curb is present, I put the striping completely on the pavement.  Generally speaking, I would avoid placing striping on top of a joint where expansion or pavement cracking can ruin the striping prematurely.   

    Regarding widths of parking spaces, the standard width that I've seen and used is 9'.  You're right that vehicles are getting larger but a 9' wide parking space makes sense since 9' is an acceptable lane width and vehicles are traveling at low speed entering or exiting a parking space.  If you have a situation where larger vehicles (trucks, buses, or RVs) are going to be using the parking lot, you can use the lengths and turning radii of those vehicle types to increase the width of aisles and the lengths of the spaces to accommodate them.

    ------------------------------
    James Talley
    Sterling VA
    ------------------------------

    Original Message


  • 12.  RE: Lane width

    Posted 03-07-2019 07:21 PM
    Edited by Tirza Austin 03-15-2019 12:02 AM
    Parking dimensions:
    Being a Structural Engineer, my only knowledge about it was from the PCI manual on parking structures which I referred to in design of precast concrete parking structures. I'm not sure if parking space has been increased.  I suggest you refer to the PCI website, or for more info on parking marking, the Canadian Parking Association.
    The manual I used shows single lines  of separation between parking spaces. That's what I see in most parking lots, but occasionally I see double lines to ensure enough spaces are left between vehicles. I assumed that was voluntary by the owner of parking lot. Perhaps you can check the latest issues of the above mentioned references and advise.


    ------------------------------
    Neil Kazen, M.Eng., M.Sc., P.Eng.
    FASCE, FCPCI, FEC,
    Retired Structural Engineering Manager, Transportation Division, SNC-Lavalin
    Toronto, Ontario, Canada
    ------------------------------

    Original Message


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