Warning Light on 2007 Nissan Altima

I have a warning light that came on I have no owners manual the light is a black circle with a clock at the 12:00 position and what appear to be sound waves to the right is 0.5h. Can you tell me what this means and can I safely drive the car

1 answer
I am not sure if this link has any up dated information to what you already have
http://www.courtesyparts.com/pdf/2007-Nissan-Altima.pdf
it is a pdf link to the owners manual but may have updated information. Could it be a low tire indicator? Tire Pressure Monitoring light. Stop at any garage and ask them if they know what the light is, anyone should help out of common courtesy.