Dodge 2009 Caravan - Manual (Page 366)

Tread Wear Indicators
Tread wear indicators are in the original-equipment tires
to help you in determining when your tires should be
replaced. These indicators are molded into the bottom of the tread
grooves. They will appear as bands when the tread depth
becomes 1/16 in (2 mm). When the tread is worn to the
tread wear indicators, the tire should be replaced.
Tire Life
The service life of a tire is dependent upon varying
factors, including, but not limited to:
• Driving style
• Tire pressure
• Distance driven
1 — Worn Tire
2 — New Tire
364 STARTING AND OPERATING