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Current IES standards refer to pedestrian lighting in terms of minimum vertical illuminance 1.5 m above pavement level. Analysis is made to find the vertical illuminance 1.5m above pavement level facing oncoming traffic for typical street lighting configurations. Three types of calculation grids were used to simulate pedestrians on the side walk, on the street and on the median. Streets with and without median are studied with various streetlighting layouts such as staggered, and along both sides of the street. It was found that in most cases the vertical illuminance on a two way street peaks on one side of the street while, it is minimal on the other side of the street at the same lateral axis. Plan diagrams of streets showing the locations of vertical illuminance greater than 1 foot-candle and less than 0.2 foot-candle are presented.

both use vertical illuminance 1.5 m above the ground as a design criterion for the lighting of pedestrians. While vertical illuminance has the advantage of being easy to calculate and measure, visibility is based primarily on target contrast. A central question related to the visibility of pedestrians is whether drivers need to see the whole pedestrian or can they infer the presence of a pedestrian by recognizing any part of the pedestrian's shape. The objective of this work was to first explore various pedestrian contrast profiles that could exist and then to find a simplified approach to characterize pedestrian night-time visibility. The problem was addressed through theoretical analyses and computer simulations. Pedestrian contrast was found to be bipolar and dynamic. From the contrast profiles, we developed the concept of dominant contrast, which is defined as the contrast of any part of the pedestrian that provides the highest visibility. Dominant contrast was examined as a metric for street lighting design and night time visibility for (a) an unlit street with car headlights, (b) a lit street without car headlights and (c) a lit street with car headlights. Dominant contrast was found to be a viable metric for street lighting design and night time visibility studies.

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