washington_roads

Crashes on Washington primary roads from 2016, 2017, and 2018. Data acquired
from Washington Department of Transportation through the Highway Safety
Information System (HSIS).

datasets

An implementation of multiple regression models for
count data. These include various forms of the negative binomial (NB-1,
NB-2, NB-P, generalized negative binomial, etc.), Poisson-Lognormal, other
compound Poisson distributions, the Generalized Waring model, etc.
Information on the different forms of the negative binomial are
described by Greene (2008) <doi:10.1016/j.econlet.2007.10.015>. For
treatises on count models, see Cameron and Trivedi (2013)
<doi:10.1017/CBO9781139013567> and Hilbe (2012)
<doi:10.1017/CBO9780511973420>. For the implementation of
under-reporting in count models, see Wood et al. (2016)
<doi:10.1016/j.aap.2016.06.013>. For prediction methods in random
parameter models, see Wood and Gayah (2025)
<doi:10.1016/j.aap.2025.108147>. For estimating random parameters using
maximum simulated likelihood, see Greene and Hill (2010)
<doi:10.1108/S0731-9053(2010)26>; Gourieroux and Monfort (1996)
<doi:10.1093/0198774753.001.0001>; or Hensher et al. (2015)
<doi:10.1017/CBO9781316136232>.

Jonathan Wood

flexCountReg

Estimation of a Variety of Count Regression Models

Guillermo Basulto-Elias

washington_roads function

Data frame compiled from roadway, traffic, and police-reported crash data
that has 1,501 rows and 13 columns:<dl>
 <dt>ID</dt>
<dd>Anonymized road ID. Factor.</dd> <dt>Year</dt>
<dd>Year. Integer.</dd> <dt>AADT</dt>
<dd>Annual Average Daily Traffic (AADT). Double.</dd> <dt>Length</dt>
<dd>Segment length in miles. Double.</dd> <dt>Total_crashes</dt>
<dd>Total crashes. Integer.</dd> <dt>lnaadt</dt>
<dd>Natural logarithm of AADT. Double.</dd> <dt>lnlength</dt>
<dd>Natural logarithm of length in miles. Double.</dd> <dt>speed50</dt>
<dd>Indicator of whether the speed limit is 50 mph or greater.
 Binary.</dd> <dt>ShouldWidth04</dt>
<dd>Indicator of whether the shoulder is 4 feet or wider.
 Binary.</dd> <dt>Fatal_crashes</dt>
<dd>Total number of non-intersection fatal crashes for the
 road segment</dd> <dt>Injury_crashes</dt>
<dd>Total number of non-intersection Injury crashes for
 the road segment</dd> <dt>Animal</dt>
<dd>Total number of non-intersection animal-related crashes for
 the road segment</dd> <dt>Rollover</dt>
<dd>Total number of non-intersection rollover crashes for the
 road segment</dd>
</dl>

Format

Washington Road Crashes — washington_roads

Data frame compiled from roadway, traffic, and police-reported crash data
that has 1,501 rows and 13 columns:<dl>
 <dt>ID</dt>
<dd>Anonymized road ID. Factor.</dd>

 <dt>Year</dt>
<dd>Year. Integer.</dd>

 <dt>AADT</dt>
<dd>Annual Average Daily Traffic (AADT). Double.</dd>

 <dt>Length</dt>
<dd>Segment length in miles. Double.</dd>

 <dt>Total_crashes</dt>
<dd>Total crashes. Integer.</dd>

 <dt>lnaadt</dt>
<dd>Natural logarithm of AADT. Double.</dd>

 <dt>lnlength</dt>
<dd>Natural logarithm of length in miles. Double.</dd>

 <dt>speed50</dt>
<dd>Indicator of whether the speed limit is 50 mph or greater.
 Binary.</dd>

 <dt>ShouldWidth04</dt>
<dd>Indicator of whether the shoulder is 4 feet or wider.
 Binary.</dd>

 <dt>Fatal_crashes</dt>
<dd>Total number of non-intersection fatal crashes for the
 road segment</dd>

 <dt>Injury_crashes</dt>
<dd>Total number of non-intersection Injury crashes for
 the road segment</dd>

 <dt>Animal</dt>
<dd>Total number of non-intersection animal-related crashes for
 the road segment</dd>

 <dt>Rollover</dt>
<dd>Total number of non-intersection rollover crashes for the
 road segment</dd>


</dl>

washington_roads: Washington Road Crashes

Description

Usage

Arguments

Format