I agree with Bob, 10 minute trips are hard on a car in cold weather! And brutal on fuel efficiency. Particularly if you don't use a block heater. Your engine probably
never warms up! The whole drivetrain certainly doesn't warm up.
a) you warm your car?? and if so how for how long? or
Normally: 850w block heater about an hour in the really cold temps, with an AC space heater on 750w for 30 minutes.
b) drive fairly quickly after starting?
Drive gently until things start to limber up.
c) have you noticed a major drop in MPG in winter?
Yup.
9 reasons why your winter fuel economy bites! - MetroMPG.com
Although haven't been hit as hard this winter (Nova Scotia south shore is balmy compared to eastern Ontario).
d) does shifting to neutral @ red lights really work ???
It saves a small amount of fuel, yes.
Welcome to the forum!