just finished eating at hooters w/ a friend and on my way home i see this machine w/ cones in front and a sign that read emissions tester, what exactly does an emissions tester do? its sitting at the onramp to 75south right before plano parkway.

It sniffs exhaust fumes as you pass by

O_O we have those in texas

turnt he car off as you drive by it =] and coast it.