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I.  PurposeThe purpose of this policy is to provide for the uniform application of criteria used to assist indetermining whether destination lighting should be provided at various types of intersectionsthroughout the Secondary Road System in Linn County. For destination lighting to be effective, itshould be installed in accordance with criteria uniformly established and in a cost-effective manner.This policy enhances the safe use of the Linn County Secondary Road System and provides for

continuity with State Primary Roads and adjacent secondary roads.

II.  ScopeThis policy pertains to the use of destination lighting for intersections on roads under the jurisdiction of theLinn County Secondary Road Department. The destination lighting policy for Linn County conforms tothe Traffic and Safety Manual for lighting of rural intersections as adopted by the Iowa Department of Transportation. This policy provides guidance applicable to Linn County Secondary Roads and outlinesthe basis for the engineer’s determination of when and how to provide proper destination lighting atintersections.

III.  ObjectivesThe objectives of this policy are to establish when destination lighting should be considered, and to

delineate where destination lighting shall be placed to enhance the safe use of secondary roads withinthe county secondary road system.

IV.  Definitions1) Average Daily Traffic (ADT): Average daily traffic is the traffic count on any road based on theofficial counts conducted by the Iowa Department of Transportation. These counts are based on actualfield data and traffic engineering studies.

2) VPD: Vehicles per day

3) Destination lighting: Lighting placed for the purpose of highlighting or attracting the attention of through traffic to the existence of an intersection or the possibility of conflicting turning movements at

night.

4) Channelized Intersections: An intersection with permanent delineation devices separating lanes such asislands, concrete barricades or raised curb sections.

5) T-Intersections: Intersections where one road terminates at another road so that the resultingintersection resembles the letter “T”.

8) P.C.C.: Portland Cement Concrete

Distribution:Secondary Roads, Board of Supervisors,

Intranet

 BOARD OF SUPERVISORSCounty of Linn, Iowa

Revision No.:

Reference:BOS Minutes: 10/09/2002

10/08/2002

Directive Number:

Approval Date:

10/09/2002

Effective Date:

10/09/2002

Policy Section & Number:

OP - 009

SUBJECT:Secondary Road Destination Lighting

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9) A.C.C.: Asphalt Cement Concrete

10) Seal Coat: Asphalt Cement with crushed rock surface

11) Hard Surfaced Road: Roads that are P.C.C., A.C.C. or Seal Coated, maintained by Linn Countyand shown as such on the Linn County Hard Surface Map.

12) Paved Road: Road Surfaced with A.C.C. or P.C.C.

V.  Procedure

ApplicationLinn County Secondary Roads Department may consider installation of destination lighting fixtures toexisting power poles located near secondary road intersections that meet the following requirements*:

1. Channelized Intersections

•  Speed Limit > 45 m.p.h.

•  Paved Road

•  ADT >1750 VPD

2. T-Intersections

•  Speed Limit > 45 m.p.h.

•  Hard Surfaced Road

•  ADT > 600 VPD

*The Linn County Engineer may evaluate hard surfaced roads not meeting all of the above requirementsfor application of destination lighting in special circumstances. Situations that may warrant specialconsideration include: temporary destination lightings, low visibility, horizontal and vertical curves, andspecified detour routes for construction projects. In addition to the installations enumerated above,additional intersection lighting may be evaluated for use when deemed appropriate by the county engineer.

Maintenance and Continued UseThe service life of destination lighting fixtures and luminaries depends on many factors including qualityof equipment, type of support, and weather conditions. Cost-effectiveness is the deciding factor for theselection of luminaries by the Linn County Secondary Road Department. Changes in facilities can alsonegate the continued use of such lighting. Examples of this include improved signage reflectivity orplacement, intersection geometry, and surface delineation. The Linn County Engineer will determine whenand whether replacement of luminaries is necessary.