I'll leave it to others to answer the first part, but as for the second part: is it safe to drive to Panama? -
I take it you're talking about the Pan-America Highway, which lots of people travel every year. I've just looked at the online book written in 1997 by the 73 year old war veteran with a leaky heart valve who did the trip in an RV!
Right now there's a group of British university students who are driving an electric sports car the entire length (Alaska to Tierra del Fuego), and they're presently in Peru.
Check out their blog http://www.racinggreenendurance.com/blog/
Most people who drive the highway say the biggest danger is livestock which wanders onto the road. The second danger is TOPES (speed bumps) which are plentiful and often unmarked.
Here's the website of some other people who did the trip in 2006 http://www.go-panamerican.com/index.php
"Safe" is a relative thing - for example you are about 45 times more likely to be injured riding a motorbike than driving a car. almost 6 years ago