There are different kinds of "in town" driving...... If you drive in very heavy traffic, and spend 30% of your time stopped at stop lights or inching along at 5 mph in heavy traffic, mid teens MPG is typical. If you drive at moderate speeds for, say, 1/2 mile between relatively brief stops / slow downs, you should be able to get low 20s MPG.
05 Taurus SEL Duratec - my daily driver
04 Taurus SES Duratec - wifes car
95 Taurus GL Vulcan winter car
Toy #1 - 86 Tbird 5.0 (original owner) - LOTS of mods
Toy #2 - 88 Tbird Turbo Coupe - LOTS of mods
02 Pontiac Grand Prix GT
67 Honda 450 Super Sport - completely customized