CozumelJen: Your driver to Newark from LaGuardia overcharged you. The fare on the meter as far as the Lincoln Tunnel would have been $30, tops, on top of which he's entitled to add $10, plus tolls, which would run about $10, plus tip. So, even with a VERY generous $10 tip, this trip should be $60. In addition, the driver is required to accept this fare, and on these terms.

However, if you're happy that he got you there in the time available, that's no reason to suddenly be unhappy over $8 & change.