There are several routes to take.
first step: You have a cell phone, she knows you have a cell phone, use the damn thing as soon as you realize that you're going to be late. Set a definite time to be home and stick to it no matter what. If you gotta take a cab, take a cab. (learned the hard way on this one
)
second step: If you failed to heed step number one, Two words "I'm Sorry". For christ sakes if you're a married male, it should be one of the automatic responses.
third step: Flowers, even if your wife, signifigant other, etc.... dosen't care much about flowers, a nice bouquet placed on the mantle with nothing said should get some notice.
fourth step: Schedule some personal time with said angry woman. Dinner (Bennihana's, Sundial) and a Movie (not Ventura Cinema)/Range Trip/Hike in the woods, should help smooth things over. Be sure to pay with the special Bookhound edition 500 dollar bills.
If these don't work, well, sounds like you're really up sh!t creek with out a paddle and the soft sounds of banjos are floating through the woods.