Yesterday cars started filling the roads outside my window around noon. As the hours passed it got worse. Initially concerned that Michelle couldn't leave her ER shift until 5pm, I started to think that might be a good thing.
The last major snow storm in Atlanta was in 2011. We were living in Augusta at the time and didn't have to worry about it. After witnessing the second fender bender in a couple hours on the street below, I decided I needed to review some safe snow-driving literature.
Our 2003 Accord has an automatic transmission. There are a handful of shift lever positions, but we've never needed anything but (D), Drive.
I tried to figure out whether I should tell her to use 2 or D3 on the way home. I came across dozens of forum posts with conflicting information. Everybody knows something on forums. I wanted something definitive.
Eventually I found the owner's manual, so here's a summary. This is applicable to 2003-2007 models, maybe some others (the new 2014 Accords have different shift positions).
Normal driving. The transmission automatically selects a suitable gear for the vehicle speed and acceleration.
Similar to D, limited to first 3 gears. Use when towing a trailer in hilly terrain or to provide engine braking when going down a steep hill. D3 can also keep the transmission from cycling between third and fourth gears in stop-and-go driving.
This position locks the transmission in second gear. It does not downshift to first gear when you come to a stop. Use second gear for more power when climbing, to increase engine braking when doing down steep hills, for starting out on a slippery surface or in deep snow, to help reduce wheel spin, and when driving downhill with a trailer.
To shift from Second to First, press the release button on the bottom of the shift lever. This position locks the transmission in first gear. By upshifting and downshifting through 1, 2, D3, and D, you can operate this transmission much like a manual transmission without a clutch pedal.
Quite a few forum posts claimed Second (2) restricted the transmission to gears 1 and 2, which is clearly incorrect (as it turns out, the meaning of the positions vary by manufacturer). Another person claimed you get more torque at higher gears. That's one of the reasons I decided to write this.
The reason Second (2) helps with slipping in snow is that it produces less torque (force) at the wheels than first. The snow and ice reduce traction (the maximum force from the adhesive capability between tire and ground), and the hope is that Second will keep you from exceeding the traction the icy road can provide. If you do exceed it, the wheels slip.
Yesterday, in Atlanta, it took Michelle almost 2 hours to make the 4 mile drive home from the hospital. A good 50 minutes of that was spent traveling a single block by West Peachtree and 10th St due to a broken down bus and people blocking the intersection trying to get to the highway. She drove in second gear the whole time.