Because of improved technology and
public-service campaigns, the number of
collisions at highway-railroad crossings per year
has declined since 2001 (see the table to the
right). Let n be the number of collisions (in
thousands) for the year that is t years since
2000. Complete parts a through e below.
Number of Collisions at Highway-Railroad
Crossings
Year
2001
2003
2005
2007
2009
2011
Number of collisions
(thousands)
3.2
3.0
3.1
2.8
1.9
2.0
