Originally Posted by
smasha
"Several short trips taken from a cold start can use twice as much fuel as a longer multipurpose trip covering the same distance when the engine is warm." --
https://www.fueleconomy.gov/feg/planning.shtml
"Vehicles are least fuel efficient and most polluting at the start of trips and on short trips. One reason for this is that catalytic converters (which reduce air pollution emissions) do not operate properly until they have warmed up. Trips of less than five kilometres generally do not allow the engine to reach its peak operating temperature." --
Fuel Consumption - Ten Top Tips for Fuel Efficient Driving
"Short trips mean the engine doesn’t have a chance to warm completely, and this greatly effects fuel economy. Group trips together if possible." --
30 fuel savers economy tips
I don't disagree with any of this. But none of it has anything to do with a bicycle as an alternative to driving 1.5 miles.
The OP is talking about a 1.5 mile distance to work and whether it's worth it to ride a bicycle. If all you were trying to say to begin with was that we burn zero gallons of gas peddling a bicycle and emit no CO2, then fine, I agree. I didn't get that out your post that I quoted.