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Appendix B Amplifying Questions

Questions that are numbered were sent to the Europeans.

Questions that are bulleted were of secondary importance.

  1. Future Developments
    • 1.1 What cutting-edge roadway and tunnel lighting research has recently been or is about to be done?
    • 1.2 We would appreciate a discussion on what you see as the next major roadway and tunnel lighting advancements.
  2. Practical Matters of Roadway Illumination Systems

    (We would greatly appreciate the benefit of your experience on matters of design, installation, maintenance, and repair of lighting systems.)

    • 2.1 Design
      • 2.1.1 What standards or lighting reference documents do you use to determine design requirements, including bibliographic listings? Would it be possible for us to receive a copy of these standards?
      • 2.1.2 We would appreciate a discussion about the lighting design for roundabouts and other specific geometric features.
      • 2.1.3 Were optimization studies done to determine your practices regarding mounting height and number/wattage of fixtures for conventional (< 20-m mounting height) and high-mast (>20-m mounting height) lighting? Are copies of such studies available?
      • 2.1.4 Do you use temporary work zone lighting at roadway construction areas?
        • In these areas, what standards or requirements do you use to determine the appropriate roadway lighting for the motorist?
        • What are the requirements for the lighting in the work area for the construction workers? May we have copies of these standards?
      • 2.1.5 We would appreciate a discussion on any light pollution concerns you may have and actions taken to abate light pollution.
      • 2.1.6 Please discuss mitigation of specific headlamp characteristics (i.e., sharp cut-off) in lighting designs, especially as applied to a visibility-based design and to the visibility of nonilluminated, retroreflective signs.
    • Is an estimate made of the amount of design work required for a particular project? How is this done?
    • What resources are committed to lighting?
    • Do the people doing the lighting design work have other duties, or do they only work on lighting? What are the qualifications for a lighting designer?
    • Does safe stopping distance play a role in the design of speed limitless autobahn lighting designs?
    • How do you deal with the differences in elevations of crossroads and ramps?
    • What types of low elevation lighting, i.e., curb or rail level, are being used for lighting on structures?
    • In the United States, as a safety requirement, we require the poles adjacent to the roadway to "break away" when impacted by an automobile. Do you have similar mandated requirements, or policies, concerning the use of breakaway poles? Are there any mandated requirements, or policies, concerning foundations for breakaway poles?
    • How does the wiring system break away? When testing breakaway devices for poles, is the wiring system in place to determine its effect on the breakaway process?
    • How is the decision to install lighting on a particular roadway made?
    • Do you use warrants for lighting?
    • Discuss your warranting conditions for continuous freeway lighting. For complete interchange lighting? For partial interchange lighting?
    • Do you use lighting programs that are compatible with CADD? Do you use Intergraph? What other CADD programs are used? Do they handle designs for both luminance and illuminance? CADD application software appears to be limited, especially for luminance design. Are your programs generated in-house or provided by vendors? Who are the vendors?
    • Discuss your wiring methods for high-mast and conventional lighting, i.e., circuit parameters (amps, volts, and volt-drop), types of insulation used, locations of fuses.
    • 2.2 Verification
      • 2.2.1 Do you have construction acceptance testing and inspection programs?
      • 2.2.2 How are the design criteria of an installation verified before the customer (state, city, township, etc.) accepts it and pays the contractor/consultant?
        • What measurement techniques are used to verify the design?
        • Do you verify calculation methods and determine if field results match calculations (check the amount of error)?
        • Do you investigate field modifications and how such modifications affect the design?
        • What inspection effort is required? We would appreciate a discussion on your preferences.
    • What do you see as the major variables affecting field measurement:
      • For the Illuminance Design Method?
      • For the Luminance Design Method?
    • How do you account for different pavement types (concrete, asphalt, aggregate, artificial brighteners), weather conditions (i.e., dampness or dryness of pavement), and wear of pavement, in the luminance readings?
    • Bidding
    • If you use competitive bidding, how do you account for the differences in photometrics between manufacturers?
    • Do you place restrictions on the luminaires as far as efficiency and utilization?
    • What are your purchasing processes and procedures?
    • Do you buy only the low-bid items?
    • Do you set up any long-term contracts with a single vendor for standardization purposes? If so, what is the duration of contract/s?
    • Operational Issues
    • Do you use noncycling HPS lamps? Why?
    • What techniques are used to identify and prevent or repair rust and corrosion of lighting pole bases and connections?
    • Do you contract out your maintenance? Could we have details? Does it include a monitoring activity?
    • Do you have a computerized inventory control?
    • How do you keep track of the infrastructure that is out on the street? Manually? Computer?
    • What are your emergency response times for weather-related accidents and also for accidents caused by humans?
    • Discuss your lighting maintenance policy/procedures for high-speed freeways.
    • 2.3 Litigation
      • 2.3.1 How do you protect against litigation if the lighting does not meet standards?
  3. Visibility Design Techniques

    (The ANSI/IESNA publication Recommended Practice for Roadway Lighting has just been revised to include the use of a visibility metric and STV, small target visibility.

    Naturally, we are very interested in any experiences you have had using visibility design techniques in your country.)

    • 3.1 Have you conducted studies comparing the results of a visibility-based design to illuminance or luminance-based designs?
    • 3.2 What is the current status of installing roadway lighting systems using a nonuniform luminance pattern based on STV (small target visibility), or close to STV, design principles in your country?
    • 3.3 What percentage of designs used visibility as a basis?
    • 3.4 What standards or lighting reference documents do you use to determine your visibility design requirements, including bibliographic listings?
    • 3.5 Are accident statistics available and do the statistics show an improvement in accident rate or an increase in driver comfort?
    • 3.6 Are any cost figures available comparing these visibility-based designs to more conventional (luminance-based) designs?
    • 3.7 Do you have feedback from drivers, bicyclists, pedestrians, on the visual acceptability (or nonacceptability) of such systems?
    • 3.8 Because it is necessary for computers to be used in calculating visibility levels (VL), discuss the program parameters, such as the equation, size and shape, and reflectance of the target, the contrast of the target, location of calculation points, the effect of vehicle headlights, etc.
    • 3.9 Do you find differences in the resulting lighting systems when different types of targets are used? For example: Would a three-dimensional shape (such as a soccer ball shaped target) yield a different lighting system than one designed around a two-dimensional flat target of similar size and reflectance qualities?
    • 3.10 We would appreciate a discussion on the visibility measurement techniques used to verify design.
    • 3.11 We would appreciate a discussion on the adequacy of lower luminance levels to be used with STV design methods.
      • 3.11.1 Do you consider headlight contribution in a visibility-based design and how is this affected by different headlamp designs?
    • 3.12 We would appreciate a discussion on the adequacy of STV designed lighting systems in varying (particularly wet or snow) weather conditions.
    • 3.13 We would appreciate a discussion on the various authorities' specifications, inspection, and testing requirements for luminaires used with visibility-based design methods.
      • 3.13.1 How repeatable do you find the luminaires from a photometric viewpoint? For example, do luminaires installed in different years give the same measurements on the street?
    • 3.14 Is there a difference in driver eye heights used in European STV designs?
  4. Luminance Design Techniques
    • 4.1 How do you account for glare?
    • Do you find that luminance designs fit into interchange areas that have varying widths and curved roadways and slower speed crossroads?
    • Do you apply luminance to bridge lighting or partial interchange lighting where you may only have a few lights?
    • We notice that a design based on luminance tends to push the luminaire out over the roadway, while maintenance desires the luminaire over the roadway's shoulder. Is this an issue and how has this issue been addressed?
    • What type of luminaires do you find most useful and why?
    • What standard do you use to determine the proper light level and what Candela/ m2 values do you use? What values for Glare ratio?
  5. Illumination of Tunnels, High-Mast, Signs, Rest Areas, etc.
    • 5.1 Tunnels
      • 5.1.1 We would appreciate a discussion on the various methods of lighting tunnels used in your jurisdiction (pro-beam, counter-beam, symmetrical, light guides, etc.)
      • 5.1.2 What is your experience with the use of sunscreens before the tunnel portal?
      • 5.1.3 What standards or lighting reference documents do you use to determine your design requirements?
        • What design methods are used to determine tunnel lighting levels? (e.g., fixed values, L20, Lseq., snow, atmospheric luminance, exterior contribution in the threshold area)?
      • 5.1.4 Do you account for glare in tunnel lighting designs?
      • 5.1.5 How do you determine what is a tunnel and what is an underpass?
        • How do you light underpasses?
        • When are underpasses or tunnels not lighted?
      • 5.1.6 Please discuss your lighting design techniques for very long tunnels, including fixture mechanical characteristics, wiring methods, controls, hypnotic effects, and backup power requirements.
      • 5.1.7 What has been your experience in the use of induction fluorescent for tunnels, walkways, and bikeways? In particular, what has been the maintenance personnel's experience?
    • Are the road design speeds maintained throughout the tunnel or are they reduced?
    • What design programs do you have to address tunnel lighting?
    • How are your tunnels maintained (i.e., washing, relamping, etc.)?
    • Are fire/smoke issues considered in the tunnel equipment? Are materials such as PVC allowed?
    • What materials are used in tunnel construction? Are walls and ceilings tile, concrete, shotcrete, other?
    • Do you consider fluorescent lighting?
    • Are most tunnels luminaires overhead or wall mounted?
    • Are tunnel exits provided with increased lighting levels?
    • 5.2 High-Mast (Mounting Heights > 20 m) Lighting
      • 5.2.1 What is the experience of using high-mast lighting of roadways and interchanges compared with usual pole heights of 10- to15-m range?
      • 5.2.2 We would appreciate a discussion on your experiences with mounting heights, number and wattage of fixtures, photometric patterns, and types of lamps for high-mast lighting.
        • We would appreciate a discussion about the design techniques you use for high-mast lighting (e.g., visibility-based design? uniformity level on high ramps in interchanges? how effectively are grade changes considered?).
    • 5.3 Signs
      • 5.3.1 We would appreciate a discussion on the various sign lighting methods used in your jurisdiction (e.g., what light levels (illuminance or illuminance) and uniformities, types of luminaires, light sources, and locations are used?)
      • 5.3.2 Due to cost and energy concerns, many signs now depend on retroreflective materials and illumination from vehicle headlamps. Given the sharp cutoff of the typical European low-beam pattern, do you experience any problems with proper and timely sign detection, recognition, and legibility?
        • What are your plans relative to making sure all signs will be detected and read and understood in sufficient time for drivers to take proper action?
    • Do you accept lower levels for sign lighting in areas where solar power is used?
    • 5.4 Decorative Lighting
      • 5.4.1 What types of newer residential and urban street lighting treatments are being used?
      • 5.4.2 What are your decorative illumination design criteria, (e.g., glare, illuminance, luminance, semi-cylindrical?)
  6. Pavement Reflection Factors
    • 6.1 We would appreciate a discussion about the various reflectance factors used in luminance and visibility-based designs.
    • 6.2 What is your experience with the effects of R-factors changing due to pavement age, aggregates, rutting, seal coat types, super-elevation, and texturing?
    • 6.3 Is the reflectance of future roadway treatments considered or controlled (e.g., are any special pavement toppings or cover coats or other techniques being used to control or improve pavement reflectivity?)
      • 6.3.1 What effect do these have on sky glow?
    • 6.4 We would appreciate a discussion about variations in off-roadway reflectances under varying weather conditions and how that would impact luminance level requirements.
    • Do you consider worst-case condition for dry pavement?
    • Do the R-tables adequately describe the roadway's reflectance characteristics?
  7. Experience with Counter-Beam vs. Pro-Beam Technology
    • 7.1 We would appreciate a discussion on accident history for pro-beam, counter-beam, and asymmetric systems.
    • 7.2 Do you consider using pro-beam or counter-beam on divided highways or tunnels and are there object identification advantages of one vs. the other?
    • 7.3 We would appreciate a discussion on transition adaptation from pro-beam to counter-beam systems and from HPS/LPS to metal halide systems.
    • 7.4 We would like to discuss with you the relative position and speed detection of drivers in negative contrast situations (counter-beam).
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Page last modified on November 7, 2014
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