Description

An experiment was performed in Sweden in 1961–2 to assess the effect of a speed limit on the motorway accident rate. The experiment was conducted on 92 days in each year, matched so that day j in 1962 was comparable to day j in 1961. On some days the speed limit was in effect and enforced, while on other days there was no speed limit and cars tended to be driven faster. The speed limit days tended to be in contiguous blocks.

Usage

Format

This data frame contains the following columns:

year

1961 or 1962.

day

of year.

limit

was there a speed limit?

y

traffic accident count for that day.

Source

Svensson, A. (1981) On the goodness-of-fit test for the multiplicative Poisson model. Annals of Statistics, 9, 697–704.

References

Venables, W. N. and Ripley, B. D. (1999) Modern Applied Statistics with S-PLUS. Third Edition. Springer.