Warrants

Continuous
freeway
 lighting may be warranted by
at least one
 of the conditions described in the following table.
Warranting Conditions for Continuous Freeway Lighting
Case
Warranting Conditions
CL‑1
Sections
in and near cities
 where the current average daily traffic (ADT) is 30,000 or greater.
CL‑2
Sections where three or more successive interchanges are located with an average spacing of 1.5 miles or less and adjacent areas outside the right-of-way are substantially urban in character.
CL‑3
Sections of 2 miles or more passing through a substantially developed suburban or urban area in which
one
 or more of the following conditions exist:
  • Local traffic operates on a complete street grid having some form of street lighting, parts of which are visible from the freeway
  • The freeway passes through a series of developments such as residential, commercial, industrial and civic areas, colleges, parks, terminals, etc. that include lighted roads, streets, parking areas, yards, etc.
  • Separate cross streets, both with and without connecting ramps, occur with an average spacing of 0.5 miles or less, some of which are lighted as part of the local street system
  • The freeway cross section elements, such as median and borders, are substantially reduced in width below desirable sections used in relatively open country.
CL‑4
Sections where the ratio of night to day crash rates is at least 2 times the statewide average for all unlighted similar sections, and a study indicates that lighting may be expected to result in a significant reduction in the night crash rate.
Because the ratio of night to day crash rates for a given section of roadway cannot always be statistically verified, this measure must be considered as an aid to design rather than an absolute rule. Engineering judgment should be exercised when using this warrant.
For streets and highways other than freeways, AASHTO has not established continuous lighting warrants for the installation of roadway lighting that satisfy all conditions. In general, lighting may be considered for those locations where the relevant governmental agencies agree that lighting would contribute substantially to the safety, efficiency, and comfort of vehicular and pedestrian traffic.
Continuous lighting may be provided for all major arterials in urbanized areas and for locations or sections of streets and highways where a study indicates that lighting would significantly reduce the nighttime crash rate.