If this happens while driving in an interference engine ,you wont drive very far, it will quickly stop running,and possibly bend a few valves in the head, not to mention possible piston damage also,anytime one breaks on an interference engine it will hurt them.

Here's how....
When the belt breaks on interference engine the timing sequence of the entire valve train will cause massive danage and failure to the valves and pistons. The timing belt is just that. It opens and closes the valves in the correct sequence of the general movement of the cycles of a four stroke engine #.1 Intake, #2. Compression, #3. Ignition, #4. Exhaust. When the timing belt breaks The valves stop moving up and down in the correct sequence of the rotation of the camshaft. For a very few seconds the crankshaft continues to rotate the connecting rods and pistons up and down slaming into the open out of phase valves till the engine destroys itself and completely stops running.

Your's is 99 model more than likely NOT an "interference engine" though ,there wasn't man of them built after the mid,90s. So it may be ok, you might need to look in a manual though to find out if it is,the owners manual provides some of this information,in the back under maintenance it should tell about it. I hope your's is not an interference engine. Go ahead and pull out that bolts and install a new belt. Good luck