Bicycle Safety Guide and Countermeasure Selection System
Lighting illuminates the intersection. http://www.pedbikeimages.org/ - Dan Burden
Although bicyclists riding during dark conditions are generally required to have appropriate lighting on their vehicles or persons, requirements vary from state to state and sometimes bicyclists do not comply with the requirements. Good illumination improves nighttime bicyclists visibility to other road users and helps bicyclists see surface conditions and obstacles or people in the path of travel. Data from five years (2005-2009) of North Carolina bicycle-motor vehicle crashes indicate that about one quarter of reported collisions and more than half of bicyclist fatalities occurred during non-daylight conditions, likely exceeding the proportion of riding that occurs under these conditions. Similarly, analyzing six years (2005-2010) of reported crash data in Chicago found that 22 percent of bicycle crashes and 40 percent of bicyclist fatalities occurred after sunset. Bicyclists, particularly commuters, may have to ride during early dawn hours or be caught by twilight, particularly in the winter months.
Improved roadway lighting may help to reduce crashes that occur under less than optimal light conditions. Intersections and trail crossings may warrant higher lighting levels than roadway segments. Good lighting on roadways, bridges, tunnels, and shared-use paths is also important for personal security. Tunnels may even require lighting during the day, depending on the length.
Lighting improvements are typically thought of as an urban and suburban treatment, but there may be situations where lighting improvements are appropriate in rural locations. Examples of such locations might include rural roadways that serve as bicycling connectors between outlying or neighboring population areas and urban centers, and intersections or shared-use trail crossings used by significant numbers of bicyclists. More research is needed on the safety and mobility benefits of lighting improvements to bicyclists and pedestrians. The American Association of State Highway and Transportation Officials guide recommends using average maintained illumination levels of between 5 and 22 lux, with higher lighting levels used if needed for personal security reasons. The Colorado DOT Lighting Design Guide Handbook also provides guidance for streets and paths. Additional roadway lighting resources include AASHTOs 2005 Roadway Lighting Design Guide and NCHRP Report 05-19 Guidelines for Roadway Lighting Based on Safety Benefits and Costs.
Lighting is a complex treatment requiring thoughtful analysis. Not only are there safety and security issues for bicyclists, pedestrians, and motorists; but potential light pollution, long-term energy costs, and aesthetics also are factors. With good design, lighting can enhance safety of the bicycling (as well as pedestrian) environment and improve the ambience of areas of nighttime activity.
Illuminating the roadway surface and surroundings enhances the safety of all roadway users and optimizes visibility of bicyclists (and pedestrians) during low-light conditions, particularly in locations where high numbers of bicyclists may be expected such as commuter routes, routes to and from universities, intersections and intersections with shared-use paths. Personal security of bicyclists and pedestrians is also improved.
Costs can vary depending on the fixture type and service agreement with local utility, as well as if other improvements are made to the streetscape at the same time. Also, though not included below, average approximate underpass lighting costs can range from $350 to $3,400 each, and crosswalk lighting can range from approximately $10,750 to $42,000 per crosswalk.
The cost range for in-pavement lights is very broad; based on manufacturer differences, roadway widths, and project-specific factors. Usually, in-pavement lights are installed as a system, which is the reason the total cost of installing lights at a location is included here, as opposed to an individual light cost.
Authors and Acknowledgements