Highway1  R Documentation 
Highway Accidents
Description
The data comes from a unpublished master's paper by Carl Hoffstedt. They relate the automobile accident rate,
in accidents per million vehicle miles to several potential terms. The data include 39 sections of large
highways in the state of Minnesota in 1973. The goal of this analysis was to understand the impact
of design variables, Acpts
, Slim
, Sig
, and Shld
that are under the control of
the highway department, on accidents.
Usage
Highway1
Format
This data frame contains the following columns:
 rate

1973 accident rate per million vehicle miles
 len

length of the
Highway1
segment in miles  adt

average daily traffic count in thousands
 trks

truck volume as a percent of the total volume
 sigs1

(number of signalized interchanges per mile times len + 1)/len, the number of signals per mile of roadway, adjusted to have no zero values.
 slim

speed limit in 1973
 shld

width in feet of outer shoulder on the roadway
 lane

total number of lanes of traffic
 acpt

number of access points per mile
 itg

number of freewaytype interchanges per mile
 lwid

lane width, in feet
 htype
An indicator of the type of roadway or the source of funding for the road, either MC, FAI, PA, or MA
Source
Carl Hoffstedt. This differs from the dataset Highway
in the
alr4
package only by addition of transformation of some of the columns.
References
Fox, J. and Weisberg, S. (2019) An R Companion to Applied Regression, Third Edition, Sage.
Weisberg, S. (2014) Applied Linear Regression, Fourth Edition, Wiley, Section 7.2.