by Professor Mark Sutherland, University of Toronto.

http://thorin.adnc.com/~topquark/fun
/JAVA/collision/collision.html

Control the ratio of initial to final velocity in a collision between two equal and elastic point masses. Displacement is plotted in both the target rest and center of mass frames.

Professor Sutherland has a collection of physics applets and tutorials at fun@learning.physics.

Tutorial from Java Lab at the University of Oregon Department of Physics.

http://zebu.uoregon.edu/
nsf/mo.html

Accelerate a rail car with cannon shots; collide rail cars all in 1D.

A Multimedia Physics Studio tutorial by StudyWorks! online.

http://www.physicsclassroom.
com/mmedia/momentum
/cba.html

Includes descriptions, animations and prblems on various collisions, mostly in 1D, but with one 2D traffic bender.

Another insightful JAVA Applet by Fu-Kwun Hwang, Department of Physics, National Taiwan Normal University.

http://www.phy.ntnu.edu.tw/java/
collision1D/collision1D.html

from his collection at the NTNU Virtual Physics Laboratory.

Several excelent sites:

http://www.nhtsa.dot.gov/index.html

http://www.mchenrysoftware.com/genintro.html

http://www.tarorigin.com/art/Lmartinez/

The last includes online portions of a fully-downloadable reference text -- the Accident Investigation Manual for Patrol Officers by Officer Luis Martinez.