A radical change in traffic law: effects on fatalities in the Czech Republic
Abstract: BACKGROUND: This study examines short- and long-run effects of a new-stricter-road traffic law on traffic accident-related fatalities in the Czech Republic. The law introduced tougher punishments through the introduction of a demerit point system and a manifold increase in fines, together with augmented authority of traffic police. METHODS: Identification is based on difference-in-differences methodology, with neighbouring countries serving as a control group. RESULTS: There was a sharp, 33.3%, decrease in accident-related fatalities during the first three post-reform months. This translates into 127 saved lives (95% confidence interval: 51, 204). The decline was, however, temporary; the estimates of the effects going beyond the first year are around zero. Unique data on traffic police activity reveal that police resources devoted to traffic law enforcement gradually declined. CONCLUSIONS: Tougher penalties have significant, but often short-lived effects. Weaker enforcement in the aftermath of such reforms may explain the absence of long-run effects. Language: en
Summary (5 min read)
- Each year, road traffic accidents (RTAs) result in as many as 50 million injuries and more than 1.2 million deaths, making it the ninth leading cause of death worldwide— effecting especially young people—and its importance is predicted to rise over the next two decades.
- This study evaluates the effects of a new road traffic law in the Czech Republic that became effective on July 1, 2006 (Parliamant of the Czech Republic 2005).
- The effects going beyond the initial six months are ambiguous, as many of these studies are based on short-term data and there are contradictions among those that do look at long-run effects.
- To the extent that the development of the variable of interest is similar across these countries, the control group allows estimating the counterfactual, i.e. the hypothetical scenario of what would have happened on Czech roads had the law not been enacted.
2 The Change in Czech Road Traffic Law
- The mechanics of the newly introduced DPS is straightforward and relatively strict.
- A driver who accumulates 12 points has his license revoked for 12 months, automatically and immediately.
- Maximum fines for offenses that can be solved on the spot, if driver accepts the ticket, were mostly raised twofold, but fines for speeding were tripled, as illustrated in Figure 1.10 Similarly, fines were increased for more serious offenses that are dealt with by the municipal office.
- Police regained the capacity to retain a driver’s license on the spot and if a driver refuses an alcohol test, the police can seize his vehicle or prevent the driver from continuing.
3.1.1 Data Collection
- The main data set analyzed in this paper consists of monthly regional-level data on RTA-related casualties that occurred between January 2004 and December 2008 in the Czech Republic, Germany, and Austria, obtained upon specific requests from the Czech Traffic Police Headquarters and statistical offices of Germany and Austria.11.
- I then merged this data with yearly regional-level data on the population and number of cars from Eurostat and yearly country-level data on transport and economic statistics from the same source.
- In addition, I received daily data on fatalities in Austria and the Czech Republic covering 2005 to 2008.
- Finally, from the Czech Traffic Police Headquarters.
- I have obtained detailed information on traffic police activity, such as man-hours, hours of use of speed guns, the number of cleared offenses, and the amount of collected fines.
3.1.2 Fatalities and Injuries
- Table 1 summarizes the data on RTA-related casualties in Austria, the Czech Republic, and Germany (split by former East and West) before and after July 1, 2006.
- Looking at the levels of fatalities, the Czech Republic had the highest rate per million inhabitants as well as per million cars in both periods.
- The picture is quite different when the authors look at injuries, however.
- Czech rates of RTA-related slight and serious injuries per million inhabitants are about 50 percent lower compared to Austria and Germany, while the number of injuries per million cars is still about 1/3 smaller, also known as The difference is substantial.
- The decline in injuries always exceeds the decline in fatalities, most notably for the seriously injured.
A: Totals by period before and after July 1, 2006
- Both factors are likely to increase the pool of accidents and injuries unnoticed by the police.
- Since there are no marginal fatalities, the effect of classification should be stronger in the case of serious injuries than slight injuries.
- To probe things further, I compared the police data with yearly data on road traffic fatalities and injuries from the Institute of Health Information and Statistics of the Czech Republic (IHIS).
3.1.3 Transport Statistics and the Economy
- Table A.3 presents a summary of the available transport statistics and GDP from Eurostat.
- At the same time, the average number of passengers per car was decreasing, in fact canceling out the increase in kilometers driven and resulting in a slight decrease in passenger-km per car in the Czech Republic over the period under study.
- The high intensity of transport traffic after the Czech Republic became a member of the European Union in 2004 is often mentioned as potentially elevating the riskiness of Czech roads.
- Finally, the second half of the 2000s was an era of rapid economic growth in the Czech Republic—real GDP per capita measured in 2005 Euros increased by 32 percent.
- The expectation of the effect of GDP growth on RTA-related fatalities per car is ambiguous; in the short run, one would expect increased traffic to dominate, implying a positive correlation between GDP and fatalities.
3.2.1 The Outcome of Interest
- This suggests that the intensity of road traffic was changing and grew faster in the Czech Republic relative to the two neighbors.
- An issue with using the number of cars to adjust for changes in traffic intensity can be that the number of kilometers per car or the average number of passengers sitting in a car may change.
- Both variables are very likely positively related to fatalities.
- 21This reasoning abstracts from the indirect effect of a higher number of car-kilometers on the probability of an accident working simply through more cars meeting on the road.
3.2.2 Empirical Model
- This paper employs a difference-in-differences (DD) estimator using neighboring countries as a control group.
- Tt consists of dummies for four post-reform quarters and a dummy for the fifth to tenth quarter after the reform.
- The parameter of interest is the vector β, which consists of five coefficients capturing the effects of the traffic law reform on fatalities over time.
- The well-known advantage of this estimator is that it helps with controlling for any unobserved shocks, as long as they affect the treated as well as the control group.
- The identifying assumptions of the DD estimator are common trends between the treated and the control group as well as the absence of any unobserved shock specific only to the control countries or to the treated country.
3.2.3 Validity of Assumptions
- There are good reasons to expect that factors generating shocks to RTA-related fatalities are shared among the Czech Republic, Austria, and Germany, so the neighboring countries offer themselves as natural control group.
- I did not receive any response from the German ministry, however researching publicly available resources did not result in finding any substantial law or policy change in Germany between 2004 and 2008.
- 14 of log monthly fatalities per million cars between the Czech Republic and either control country from January 2004 until June 2006 are above 0.7 and are statistically significant at any conceivable level.
- This data include Austria, the Czech Republic, former West Germany, Poland, and Slovakia.
- 24While data are available from 1996, there are frequent revisions, especially in statistics on number of cars, making the earlier data less reliable.
3.2.4 Meaning of Estimates
- In their case, the coefficients β from regression 1 represent time-varying treatment effects on the treated, as the policy change was designed and introduced by the Czech Republic itself, unlike in a random assignment.
- There can also be a potential endogeneity bias in the sense that the timing of the reform may not be random.
- Everyone was long aware that the change in the road traffic law was coming soon and this may have affected pre-reform outcomes, in fact generating some effects of the reform before it actually took place.
- They may also have expected the police to increase their effort around the introduction of the reform.
- 16 the longer the data for the pre-reform period.
4.1 Main Results
- The main set of ordinary least squares estimates of the effects of the new Czech road traffic law on fatalities using regression (1) are reported in Table 2.28 Specification (1) (I will refer to it as the “base result”) shows that the immediate effects of the law were substantial, but shortlived.
- To summarize, these findings provide strong evidence of substantial immediate effects of the new road traffic law on fatalities in the Czech Republic, but not much is apparent beyond that.
- Table 3 probes their base results with additional control variables.
- I first include GDP per capita, which grew faster in the Czech Republic compared to Austria and Germany, as seen in the last column of Table A.3.
- The estimates of long-run effects, that is beyond the first 12 post-reform months, are substantively and statistically insignificant.
4.2 Short-Run Development
- The availability of daily country-level data on RTA-related fatalities in Austria and the Czech Republic makes it possible to study the response tho the new law in more detail.
- There is no apparent positive or negative trend during the pre-reform period, which is reassuring.
- Importantly, the figure corroborates their main finding that the effects of the law were concentrated in the first three months, as most of the estimates for that period lie below the zero line.
- Estimates are less erratic compared to Panel A, as the restrictive model is likely to filter out some noise.
5.1 Competing Explanations and Some Theory
- The short life of the initial effects of the traffic law reform is not too surprising.
- Intuitively, as higher punishments improve drivers’ behavior, enforcement resources may be reallocated to more valuable uses.
- The police dislikes offenses as well as effort.
- There are various reasons why this simple model may capture some of the reality.
- It is also plausible that when similar large-scale changes in the law are adopted, the traffic police may already be overstretched.
5.2 The Data on Police Activity
- This subsection presents an analysis of a unique dataset parsed from internal monthly regional-level information on traffic police activity in 2006 and 2007 I have obtained 40See also Holler (1993) and Andreozzi (2002) for a further discussion of Tsebelis’ model.
- The number of policemen assigned to enforcement a exhibits general upward pattern over 2006 and 2007.
- 25 Tables 4 and 5 study traffic police activity in more detail.
- I use half-yearly country-level data on man-hours in enforcement ranging from 2005 to 2008 and estimate a coefficient for a second half-year, which I then use to deseason the monthly data on police activity.
- Nonetheless, the total amount of traffic police man-hours dedicated to enforcement was gradually declining from the third quarter of 2006 onwards.
5.3 What Does (Not) the Traffic Police Activity Explain?
- In sum, the police data reveal that enforcement levels were declining in the aftermath of the traffic law reform and suggest that traffic police may have put a higher share of resources into general law enforcement and police work and away from the direct enforcement of traffic rules.
- This development is in line with the outlined theory, however one should be careful before interpreting this result strictly causally.
- Only two years of data are available, so the authors cannot rule out preexisting trends or factors driving the changes in police data other than the change in the traffic law.
- It can hardly do so with respect to the sharp short-run decline in fatalities as the police presence on the roads was apparently lower during the third quarter of 2006, relative to first half of that year.
- Doing this would lead to results lacking proper interpretation.
- This study evaluates the effects of the introduction of a new road traffic law on RTA-related fatalities in the Czech Republic.
- Consistent with the literature, studying the effects of similar changes in traffic laws in other countries, I find a substantial initial response to the increase in punishments for traffic offenses.
- From 51 to 204—with point estimate of 119—human lives were saved with 95 percent certainty in that period.
- It is noteworthy in this context that traffic intensity, measured by number of cars, kilometers driven, or intensity of freight transport, was increasing substantially during the period under study.
- A continuous decline in traffic law enforcement cannot, however, explain the short-run pattern of the reaction to the legal reform.
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