Wednesday, July 27, 2005

Roadkill myths I: It just keeps getting worse

Everyone in Israel seems to have an opinion about road accidents and how to reduce them. Unfortunately, most people's opinions seem to be disconnected from the facts. With a new legislative proposal on the subject before the Knesset, I thought I'd finally launch my long-planned series.

Before I get into my opinions, I'd like to start by dispelling some of the widespread misconceptions about the facts.

Myth I: It just keeps getting worse

You hear this every time there's a major traffic accident. "It just keeps getting worse, doesn't it? Every year more people are killed!"

Fortunately, this myth is easily dispelled. Annual traffic fatalities are not on an upward trend; far from it.

Anyone care to guess in which year the most Israelis were killed in traffic accidents? (Data is available from 1949-2004.)

Would you believe 1974? And it's not even close.

Here's the raw data (available from Israel's Central Bureau of Statistics):

As you can see, it's not getting worse from year to year. But, you may insist, neither is it getting any better. Annual fatalities have been stuck at 450-550 for over fifteen years now. With all the money and effort invested in road safety, why don't we see any improvement?

Actually, there's been plenty of improvement. The above graph ignores a crucial factor: The increase in population. Israel has the fastest population growth of any developed country, due to high birth rates and immigration. If the number of fatalities stays constant while the population grows, that means the per capita fatality rate is improving!

The population graph - note especially the sharp growth since 1990, the start of the Soviet aliyah:

So in 2004, there were almost as many traffic deaths as in 1987 - but the population was about 55% higher! That means the per capita fatality rate has fallen by 38% since then.

Dividing the first graph by the second graph, let's graph the per-capita fatality rate:

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As you can see, there is a clear downtrend since the peak in the 1970s, though the improvement has been gradual since 1980.

Why is it so slow, though? We need to do better!

Ah, but even this graph omits a crucial factor: The increase in road use. Israel has a rapidly developing economy, with the standard of living improving at a fast pace. This is partly reflected in the burgeoning use of private vehicles. Twenty-five years ago, few Israelis owned cars; now, many families own two or more.

You can't assess road safety without taking into account road usage. All else being equal, the more people drive the more accidents there will be.

Road use has increased much faster than population (data available only since 1963, with annual data only since 1984):

So Israelis drove 2.6 times as far in 2004 as they did in 1987, but with about the same number of fatalities. In that time, the fatality rate per kilometer driven fell by 63%, or nearly two-thirds!

Here's the fatality rate per kilometer driven:

As this graph demonstrates, the death rate per kilometer driven improves nearly every year, sometimes significantly. This makes sense, since the roads are improved from year to year, and car safety features also improve over time.

(NOTE: I've updated these last two graphs since first posting to remove misleading interpolated data points.)

Now we can put the first graph, the raw numbers of annual fatalities, in context. Two long-term trends are at work: The year-on-year growth in vehicle use, driven by population growth and economic improvement; versus the year-on-year safety improvements to roads and vehicles, which lower the per-kilometer fatality rate. When the fatality rate drops by more than the increase in kilometers driven, the overall number of fatalities falls; when road use increases more than safety improves, the raw number of fatalities rises.

Either way, however, road safety - as measured by fatalities per capita or fatalities per distance driven - improves over time. Contrary to the myth, it just keeps getting better!

In future installments in this series, I hope to address international comparisons of Israel's road safety record.


Cosmic X said...

Nice post. Seems to me that the Israeli MSM starts bitching about road accidents when they have nothing else to report about.

Ron Coleman said...

Your graph says it all. This happens with a lot of things: "Why are we seeing so many sick children?" Because B"H we are seeing so many children. In fact we probably see fewer sick children per capita than just about ever.

Having said that: Seatbelts. Israelis smoke. Israelis probably don't wear seat belts enough.

Zman Biur said...


I don't mean to denigrate the seriousness of road accidents. When people are getting killed, the government should be paying attention and taking appropriate measures.

My point is to bring some perspective to the issue, so we can appreciate how dire it really is and what effective measures can actually be taken.


Indeed, the graphs are striking. As you say, there are ways to improve the situation. But to propose meaningful changes, you have to start by understanding the facts about the problem.

You may be right about seat belts, though, like smoking, the situation in Israel has improved greatly in recent years. I expect to talk about specific proposals in later installments. For now, just the facts.

Out of Step in Kfar Saba said...

all very interesting - but what of non-fatal accidents? monetary damage, physical damage, etc.
It is all too clear to anyone who drives that something is terribly wrong no matter what the stats say.

Zman Biur said...


I haven't had a chance to tabulate the stats for non-fatal injuries and damages, but there's every reason to assume the trends are similar. I'll make myself a note to get to it in the future.

I agree that there are problems with driving in Israel. But without the perspective offered by factual analysis, any proposed solution is just a shot in the dark.

ADDeRabbi said...

i'm curious about the demographic spread of the fatalities. is there any data available on that?

Alex said...

Very good analysis indeed.
There is a similar subject I am curious about for a long time: poverty in Israel. The mass media are pumpering it full sail, but my impression is quite the opposite since I know what povery is - I was borne in Russia. To start with, the poverty criterion is inexpedient - you are poor if your income is something like 3 times less than the average one. Just think about the absurdity - if tomorrow the income of every citizen is 10 times larger than today, it follows from the definition that the amount of poor peple will remain absolutely the same. It is high time for an honest analysis of this subject along the lines of yuor analysis of the road accidents.
Thanks again for a serious study.

ian said...

Thanks for these stats- very informative, and explained clearly.

mickeyobe said...

You may use all the graphs and statistics you want. The fact remains that 475 deaths in one year are 475 tragedies for which there is no remedy. 475 Israelis that should be with us today but, sadly, are not.

Mickey Oberman