Volvo XC90: Wheels and tires / Tread wear indicator
The tread wear indicator shows the status of the tire's tread.

The tread wear indicator is a narrow elevated strip running across the tire's
longitudinal tread grooves. The letters TWI (Tread Wear Indicator) are visible on
the side of the tire. When approximately 1.6 mm (1/16 inch) is left on the tread,
the tread will be at the same height as the tread wear indicator. Replace the tire
as soon as possible. Tires with low tread offer very poor traction in rain or snow.
Tires with tread designed to roll in only one direction are marked with an
arrow on the sidewall.
The arrow shows the tire's direction of rotation.
The tire should maintain the same direction of rotation throughout its service
life...
The following is a glossary of tire-related terms.
The tire suppliers may have additional markings, notes or warnings such as standard
load, radial tubeless, etc...
Other information:
The following information will help you report any perceived safety-related
defects in your vehicle.
Reporting safety defects in the U.S.
If you believe that your vehicle has a defect which could cause a crash or could
cause injury or death, you should immediately inform the National Highway Traffic
Safety Administration (NHTSA) in addition to notifying Volvo Car USA, LLC...
The low beam bulbs in the halogen headlights can be changed without the help
of a workshop.
Before the bulbs can be replaced, the plastic covering over the headlight must
be removed.
CAUTION
Never touch the bulb glass with your bare fingers. Grease and oils from
your fingers vaporize in the heat and will leave a deposit on the reflector, which
may damage it...