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David Keith is founder and principal of Marshall Design, Inc., a lighting design and consulting company in Boulder, Colorado. Since 1992, Marshall Design has provided services including lighting research and design for projects ranging from roadway and neighborhood development through public parks, restaurants and residential interiors.
David has extensive exterior and roadway lighting design experience, as principal designer on projects including the I-70 & C-470 Interchange, roadways at the Denver International Airport, the Boulder County Courthouse Plaza, and numerous other roadway, commercial and residential development projects. Significant recent projects include:
Marshall Design, Inc. provided lighting design services for the proposed CDOT parking facility at I-70 and US 40 in Golden. This work included design of the area lighting system in accordance with the new Colorado state law on outdoor lighting as well as public presentations of the proposed design. The design includes low-glare flat glass luminaires on sufficiently tall poles to meet the IESNA criteria while minimizing spill light, with a Lighting Power Density of only 0.026 Watts per square foot.
Marshall Design, Inc. provided lighting design services for the I-70 & C-470 interchange during 2002-3. This work included review of the existing and proposed high mast lighting system, followed by a redesign of the entire interchange lighting system in accordance with the new Colorado law on outdoor lighting equipment.
David Keith of Marshall Design, Inc. presented two papers at the 2002 IESNA Annual Conference on his research into roadway lighting systems and Unit Power Density (UPD) and Unit Uplight Density (UUD). These papers will be published in the next volume of the JIES. This work discusses the energy use and equipment quantity implications of different lighting systems, comparing light sources, lamp wattage, lamp lumen ratings, luminaire distributions, maintenance characteristics and design methods. Using custom software which optimizes roadway lighting systems to meet desired criteria, this research demonstrates the importance of evaluating systems instead of lamp or luminaire characteristics. In addition, the research indicates the potential for significant reductions in UPD - and associated costs and pollution - by using appropriate lamps, luminaires, mountings and design methods . This latest paper extends the findings of previous work by David Keith published in the Journal of the IES (v29n2) discussing UPD and uplight, which concluded that the best way to reduce overall uplight is to reduce UPD. Another paper [JIES v31n2] documents the energy reduction potential from using the luminance design method of ANSI/IESNA RP-8-00 and the increase in UPD associated with equipment restrictions such as requiring full cutoff luminaire distributions.
David Keith and Jefferey Knox also presented a paper at the 2003 International Dark-Sky Assn. Conference on light pollution produced by different light sources, and one at the 2003 IESNA Conference, on evaluating color perception under different light sources.
David Keith of Marshall Design was the lighting consultant on the SH 119 from US 6 to Black Hawk upgrade project, completed in 2001. This rural mountain roadway has two lanes and serves as the principal access to the communities (and gaming establishments) in Black Hawk and Central City, and therefore is the one of the busiest roads - and most warranted lighting project - in the state. Leading issues were coordination between the Colorado Department of Transportation, the local utility and the jurisdiction of Black Hawk as well as neighborhood concerns about glare and stray light. Marshall Design, Inc. provided roadway lighting design review, revision and specification services. The resulting roadway lighting system exceeds the 1983 AASHTO standards, with only half as much light and energy use as the local utility recommended, within the stringent mounting requirements. The design uses utility approved cutoff luminaires and minimizes glare and stray light. Furthermore the anticipated expansion to three lanes can be accommodated with negligible revision to the lighting system. The local community organization commended the lighting after its installation.
Marshall Design, Inc. provided plan review services for the E-470 interchanges at US 85 and at I-76 during 2001. This technical review of the proposed high mast lighting systems included checking lamp, luminaire, layout and calculation model details. This work extended from checking the height of the tower foundations and the aiming of the luminaires to the comparison of the calculations to the specified criteria. Even the software used in the calculations was checked against independent software to ensure accuracy. The review discovered some small discrepancies between the design model and the plan documents which were easily fixed before the bidding phase, saving the owners potential problems or change orders which would cost several times the expense of the review.
David has a BS (1985) and a MS (1995) from the College of Engineering at The University of Colorado at Boulder. He is a member of the IESNA Roadway Lighting Committee, which developed the American National Standard for Roadway Lighting, ANSI/IESNA RP-8-00, the most recent standard for North America roadway lighting (and the source of the upcoming AASHTO lighting guidelines). David serves on the Standard Practice, Energy Management and Measurements & Calculations subcommittees, and as chairman of the Fundamentals & Education subcommittee. He is also the revision author for the recently revised IESNA Lighting Fundamentals section on Exterior Lighting and frequent instructor in lighting, energy and economics for classes ranging from elementary students to practicing lighting professionals. In 2002 David was honored by being named a Fellow of the IESNA.
More information about Marshall Design, Inc. is available through the world-wide web at "http://resodance.com/mdi" including images and project descriptions.
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