Wishing everyone out there a good Mother's Day. But have you noticed that it's one of the worst days to be on the road? That's because so many people are taking their mother (and the rest of the family) to a nice restaurant, and, because the son or daughter is behind the wheel, the driving is the most careful of the year (especially around for o'clock in the afternoon - shortly before dinner time). That interferes with the natural rhythm that normally exists on the roads. As a result, fewer cars make a left turn or go through an intersection on a yellow light. When the light goes green, the cars get up to speed slowly. And lane changes are not as sprightly as they usually are.
Contrast that with other special days, like Christmas or Thanksgiving. For those days, even though it can be busy, all the drivers are either trying to get somewhere quickly (Christmas shopping) or put on lots of miles (Thanksgiving trips). Which has a focus on speed and efficiency. On Mother's Day, driving speed and efficiency is not paramount. In fact, speed and efficiency is a negative, and you end up with a different traffic dynamic - one we're not used to.