Association between increase in fixed penalties and road safety outcomes: A meta-analysis
Introduction
Many motorised countries have a system of fixed penalties for common traffic offences. A fixed penalty is a fixed amount of money to be paid when a road user pleads guilty to committing a certain offence. Fixed penalties are commonly applied for speeding offences, non-use of seat belts, and other common traffic offences. Fixed penalties tend not to be continuously adjusted in line with consumer prices, but are increased steeply every few years. As an example, the Australian state of Queensland increased fixed penalties for speeding on April 17, 2003 (Watson et al., 2015). For minor violations (less than 15 km/h above the speed limit), there was a modest increase from 90 to 100 Australian dollars. For the most serious violations (speeding by more than 40 km/h), the fixed penalty increased from 255 to 700 Australian dollars.
Are increases in fixed penalties associated with a reduction in the number of traffic offences and accidents? A number of studies have been made to answer this question (Fridstrøm, 1999, Wagenaar et al., 2007, Cedersund, 2008, Maffei de Andrade et al., 2008, Tavares et al., 2008, Montag, 2014, Moolenaar, 2014, Sebego et al., 2014, Bhalla et al., 2015, Elvik, 2015, Watson et al., 2015, Killias et al., 2016). The findings are, however, not entirely consistent, and no formal synthesis of the evidence provided by these studies has been found. The objective of this paper is to summarise current knowledge regarding the association between changes (mostly increases) in fixed penalties (the term traffic fines is used synonymously) and changes in road user compliance with road traffic laws and changes in the number of accidents. Before reviewing relevant studies, theoretical perspectives on the relationship between traffic fines and road user compliance with the law will be discussed.
Section snippets
Theoretical perspectives and research questions
Economic theory offers two perspectives on the effects of increasing traffic fines on road user compliance with road traffic laws. According to the standard economic model of crime, proposed by Becker (1968) in a seminal paper, offenders weigh the costs and benefits of violations. An increase in fixed penalties increases the expected cost of committing a violation and is therefore expected to deter violations.
A game-theoretic model of crime and enforcement, on the other hand (Tsebelis, 1989,
Study retrieval and coding
Studies were identified by searching Sciencedirect and the Ovid Transport Database. The following search terms were used: “traffic tickets”, “fixed penalties” and “fines”. In addition, studies quoted in the Handbook of Road Safety Measures (Høye et al., 2015) were examined. Table 1 list the studies that were found. There are two groups of studies: (1) Studies that use some indicator of road user compliance with road traffic law as the dependent variable, and (2) Studies that use changes in the
Changes in compliance
The studies stated estimates of changes in compliance in different metrics and did not always include estimates of the standard errors. To permit a meta-analysis, all estimates must be stated in the same metric and all standard errors must be known. In general, the statistical weight assigned to an estimate in meta-analysis is:SEi is the standard error of the i-th estimate.
The oldest study, Andersson (1989), stated the percentage of cars speeding in four
Changes in violations
Before performing a meta-analysis, one should do an exploratory analysis to determine if it makes sense to proceed to a full analysis. A useful tool for performing exploratory analysis is the funnel plot. Fig. 1 shows a funnel plot of the 43 estimates of changes in violation rate. The scales were defined as recommended by Sterne and Egger (2001).
Ideally speaking, the distribution of data points in a funnel plot should be symmetric and have the shape of a funnel turned upside down. Data points
Changes in compliance
The main analysis was performed in two stages. First, a subgroup analysis was performed in order to assess the presence of a dose-response relationship between changes in fixed penalties and changes in the rate of violations. The results are reported in Table 3.
The results are inconsistent. While both a simple mean and the random-effects summary estimate indicate a weak (statistically non-significant) tendency for violations to go down, the fixed-effects summary estimate indicates an increase
Discussion
There are almost always two ways to interpret the findings of research: methodological and substantive. A methodological interpretation will often argue for rejecting findings as only showing poor data or poorly designed studies that are prone to error and bias. A substantive explanation, on the other hand, will often propose a causal interpretation of study findings.
With respect to the research presented in this paper, methodological problems can arise at two levels: the level of primary
Conclusions
The main conclusions of the research presented in this paper can be summarised as follows:
- 1.
Changes in fixed penalties for traffic law violations are, on the average, associated with small changes in the rate of violations.
- 2.
There is a dose-response relationship between the size of the increase in fixed penalties and the size of the reduction in violations. This relationship has a turning point for very large increases in fixed penalties.
- 3.
Study findings were found to vary over time and between
Source of funding
The research presented in this paper was funded by the Norwegian Ministry of Transport.
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