Total target crashes [crashes during nonpeak periods that are materially affected by camera enforcement] were reduced by an estimated 44 to 54 percent, injury crashes by 28 to 48 percent, and property damage only crashes by 46 to 56 percent during the nine month program period.
(The program was temporarily suspended, then reactivated; future evaluations may elaborate on the results.) Since analyses found low speeding detection rates during peak travel times, the target crashes (speeding-related crashes) were considered to be those that occurred during non-peak flow periods (weekends, holidays, and non-peak weekdays hours).
Effectiveness of speed cameras is typically measured in outcomes related to speed or collisions.
Speed outcomes include reductions in average speed, distribution or variance of speed, or percentage of vehicles speeding.
Automated enforcement is used in some jurisdictions to reduce red-light running and speeding. Since then, at least 92 jurisdictions (state and local) have adopted automatic enforcement, although speed cameras are not as widely used as red-light cameras.
NHTSA and FHWA have released speed camera enforcement program and operational guides with information on problem identification and program planning, communications strategies, obtaining community and other stakeholder support, processing of violations, and program evaluation ([NHTSA, 2008i]; [FHWA and NHTSA, 2008]). 3-12) The first automated speed limit–enforcement program was implemented in Paradise Valley, Arizona, in 1987 (Retting, 2010).
Monthly operating costs were about $5,000 [per camera system] ([Maccubbin, Staples, and Salwin, 2001]). A few States prohibit or restrict some forms of automated enforcement ([GHSA, 2014c]; [IIHS, 2014b] [see Table B.1]).
See NCUTLO (2004) for a model automated enforcement law. 3-14) Public surveys typically show strong support for red-light cameras and somewhat weaker support for speed cameras ([IIHS, 2014a]; NHTSA, 2004). PIRG) (Madsen and Baxandall, 2011), a federation of state Public Interest Research Groups (PIRGs), noted that such practices have become less common, but contracts may still link revenue to citations through a predetermined proportion of revenue; a variable proportion of revenues based on timeliness of fine collection, quotas, and volume-based payments; and surcharges from alternatives, such as traffic school.
The percentage of speeders was also substantially reduced when police-operated photo radar enforcement vans were present in a work zone on a non-interstate highway in Portland, Oregon, but there was no carry-over when the enforcement was not present (Joerger, 2010).
Given that there was no evidence of any accompanying publicity, there was, however, no reason to expect carry-over outside of the enforced periods.
In addition to the crash reductions, average speed was decreased by about 9 mph and speed variance [a measure related to the range of speeds and the amount of variability around the average speed] was also decreased around the enforced zones. 3-13) [In addition, an] economic analysis suggested that the total estimated safety benefits [including medical, quality of life, and other costs (emergency responders, insurance, wage loss, household work loss, legal fees, and property damage)] were from .5 [million] to .1 million per year, although other economic impacts were not considered.