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Publication Number: FHWA-HRT-05-048
Date: April 2005

Safety Evaluation of Red-Light Cameras

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Appendix A. Sources of Data by Jurisdiction

Table 19. Data sources.

Data Item Baltimore, MD Charlotte, NC El Cajon, CA Howard County, MD
Crash data Maryland CODES data from National Study Center for Trauma and MSUniversity of Maryland-Baltimore Charlotte Department of Transportation (DOT) California Highway Patrol Crash Database (SWITRS) Maryland CODES data from National Study Center for Trauma and MSUniversity of Maryland-Baltimore
Intersection traffic counts From Baltimore Traffic Management Centers (TMCs), Maryland State Highway Administration counts, MPO (BMC) counts, and vendor loop data Database of total intersection entering volumes, hardcopied TMCs, midblock counts, and approach volumes on signal plans El Cajon turning movement counts and permanent station countsLink volumes from the area MPO (SANDAG) Howard County TMCs and midblock ADTsMaryland State Highway Administration (MDSHA) TMCs and midblock ADTs
Number of approach lanes, medians, turn lanes Aerial photos from Baltimore GIS data Signalized: Most are from detailed signal plans, a few from aerial photographsUnsignalized: Estimated from aerial photos Signalized: Signal plansUnsignalized: Aerial photos, signal warranting study reports, and drawings of adjacent intersections Signalized: Howard County and MDSHA signal plans, aerial photos
Intersection "change" data Baltimore historical timing sheets No signal timing change data available. El Cajon historical signal timing sheets From historical signal plans and log maintained by Howard County staff
Traffic signal phasing data Baltimore printouts of current signal timing Charlotte signal timing system El Cajon printouts of current signal timing Howard County and MDSHA signal plans
LEDs and backplates No data available From signal drawings Used by El Cajon, but no formal installation dates were available From log maintained by Howard County staff
RLC installation date City of Baltimore Traffic Engineering Division Charlotte DOT El Cajon Traffic Engineering Division and Police Howard County staff
RLC signing City of Baltimore policy Charlotte DOT policy El Cajon Traffic Engineering Division policy Howard County policy
RLC ticket protocol City of Baltimore Traffic Engineering Division Charlotte DOT El Cajon Traffic Engineering Division Howard County staff

Table 19. Data sources. Continued.

Data item Montgomery County, MD San Diego, CA San Francisco, CA
Crash data Maryland CODES data from National Study Center for Trauma and MSUniversity of Maryland-Baltimore California Highway Patrol Crash Database (SWITRS) California Highway Patrol Crash Database (SWITRS)
Intersection traffic counts Montgomery County ADTs and TMCs San Diego machine counts and turning movement counts San Francisco ADT files, hardcopied turning movement counts and approach countsState-maintained ADTs
Number of approach lanes, median presence, presence of turn lanes Signalized: Signal plans supplemented with aerial photosUnsignalized: Intersection drawings on TMCs Signalized: Signal plans (outdated), aerial photographs, non-scale drawings from reportUnsignalized: Work-order requests, sketches on turning movement counts, and coders assumptions based on volume Signal plans, pavement marking drawings, and aerial photographs
Intersection "change" data Montgomery County historical signal timing files San Diego historical timing files San Francisco historical timing cards
Traffic signal phasing data Montgomery County signal timing files San Diego signal timing files San Francisco signal timing files
LEDs and backplates These data are not maintained Requested but never received from City of San Diego maintenance staff Although the city uses LEDs, it was not able to provide installation dates
RLC installation date Montgomery County Department of Public Works (DPW) City of San Diego Traffic Engineering Division San Francisco Department of Parking and Traffic (DPT)
RLC signing Montgomery County DPW provided general information City of San Diego Traffic Engineering Division policy San Francisco signing database
RLC ticket protocol Montgomery County DPW City of San Diego Traffic Engineering Division San Francisco DPT

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