Two days each week I have to go out to a client's office about 40 km from home. Only one route works to get me there, and that route includes the infamous Eisenhower Expressway (I-290) leading to the west from the Chicago Loop.
In the last few years, though, the Illinois Dept. of Transportation and neighboring agencies have created Travel Midwest, which has vast stores of traffic data. This has helped me stay sane. The site allows you to query the database to find out, in simple visual charts, when traffic is worst.
This chart compares my morning commute from the Circle Interchange to Wolf Road (22½ km). The red line shows travel times Monday through Thursday; blue line shows Friday times. (The data are from the last 12 months.) This shows why I hit the road around 8:30, instead of earlier, which gets me to the Eisenhower around 9 and here by 9:30:
But here's the return trip; again, Monday-Thursday is red and Friday is blue:
Then there's the chart going the opposite direction right now:
In the chart above, the thick red line shows the mean travel time, and yellow area shows 1 standard deviation on either side of the mean. The lines at 15, 23, and 56 minutes represent 88 km/h (full legal speed), 56 km/h, and 24 km/h. At the moment, the 65-minute travel time means traffic is moving at the breakneck speed of 20.6 km/h, which most bicyclists would find a relaxing speed.
I think I'll stay put for a while. Damn.
Having this information makes it relatively easy not to travel when everyone else is on the road. Yeah, I get home a little later, but the cost to me of spending 30 minutes in slow traffic is higher than the cost of shifting my commutes an hour forward.