Underinflated tires are unsafe, waste fuel and lead to premature tire replacement. Simple, routine pressure checks would save consumers more than having the service performed. The California Air Resources Board has adopted a measure to require shops to check and correct tire inflation of customer vehicles at every visit by July 2010. CARB is urging US EPA to mandate the same nationally.
Background
CA regulators estimate tires severely or moderately underinflated on 50%+ of nearly 30M passenger vehicles in state
Poorly inflated tires can lead to blowouts