Lighting Research Center Lighting Research Center

Research: Snowplow Operation

Rear Lighting and Signaling

Rear lighting and signaling on snowplows is important during inclement weather, especially at night. Drivers of other vehicles around the snowplow need to be aware of the snowplow's presence, and to make accurate judgments about the speed and distance of the snowplow relative to their own vehicles.

Despite the high conspicuity of many flashing and strobing light systems used on snowplow trucks, most accidents involving snowplows are rear-end collisions by other vehicles. This suggests that other drivers do not have the visual information required to estimate the speed and relative distance of the snowplow during poor weather. In fact, published vision research has demonstrated that these kinds of judgments are difficult to make when flashing or strobing lights are present.

The Lighting Research Center is currently evaluating a steady-burning light bar mounted on the rear sides of the snowplow truck, in comparison to the flashing-light configuration currently used by the New York State Department of Transportation (NYSDOT) and by many other agencies in North America. The light bar is shown in the photographs above, and the thumbnail images to the left show each configuration. (Clicking on the images to the left will animate them.) The light bars use light-emitting diodes (LEDs) which are of sufficient intensity to be used successfully as signal lights and which also result in significantly lower energy use than conventional incandescent lamps. Preliminary analysis indicates that the steady-burning light bars improve the ability of drivers to detect the relative position and speed of the snowplow.

See for yourself:

What's the best rear lighting scheme for snowplows? Please click on one of the images below to view the video clip. Which snowplow would you rather drive behind?

Click on am image to view the video clip.

   A. Flashing incandescent

   B. Linear LED array

NOTE: Each clip is large (>1 megabyte) and it may take a while to load the animations on slow connections.

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