Using sonar, infra-red or vision systems, suppliers are developing ways to detect the size of the passenger in the front seat and to measure how far back they are sitting.

ECONOMIST: A safety bet

Asked if the supplemental index is getting bigger, he responds that "new pages are constantly being added, " but that the "algorithmic nature" of Google's spider makes it hard to measure the index's size or how fast it's growing.

FORBES: Magazine Article

Utilization rates are a measure of how many rigs are working on contracts in comparison to total fleet size.

FORBES: Quick Take