August 11, 2009

The Dangers of the First Day of Rain

The first day of significant rain after a long dry period can be very dangerous on the roads. Why?
During the dry period oil, dust and other debris collect on roadways and the addition of water produces a slippery emulsion. After a few days of rain, it washes off. The other issue is that people are used to dry-road driving and driving habits (like taking that corner slower) are slow to change. There is in fact a literature on this first-day-after-a-long dry spell issue--check out: as one example.

So be really careful driving today...I have already received a number of reports of significant local accidents.


  1. It always amazes me that Seattle drivers don't know how to drive in the rain.

    Well, given the fact that they don't know how to drive in the sun, I shouldn't be surprised.

  2. Point of clarification: the Seattle drivers don't know how to drive in the sun. It's the California drivers who don't know how to drive in the rain. Unfortunately Seattle has both types. ;)

  3. I grew up back East and this was one of the first driving lessons from my dad, about the slick slurry on a road from long-delayed rain. It's a valuable thing for young drivers to know.

  4. Seattle drivers just suck peroid. Only weather They can drive in is Overcast and Cloudy.

  5. I've parked my motorcycle for the next couple of days. You can't pay me to ride on Seattle pavement today. Nothing but wet oil slicks. I'd just be asking to lay my bike down after months of dry, hot weather. Why don't people in cars know this?

  6. I have driven extensively all over the U.S. and even quite a bit in Europe, and can assure you their are a lot of real bad drivers all over this country. My guess is anytime someone calls a whole group out on something like this, it stems either from proximity to the familiar, or the natural prejudice derived from personal certitude. I know I feel that I am a better driver than 99% of the others out there, and realistically I'm better than the other 1% as well. I'll bet any one of you feels pretty much the same.

    I accept I could be wrong, though. If you have some sort of statistical evidence that proves Seattle drivers are the worst in the world, or the U.S., or wherever I would be interested in looking at it. Please post a link.

  7. What the--
    Where did anyone claim Seattle drivers were the worst?
    They just suck in their own special annoying way.

  8. Yes, there are lots of bad drivers everywhere. 99% (or more) of drivers anywhere you go don't know how to follow laws.

    I don't know how really difficult it is to follow posted speed limits, use turn signals, stop at stop signs, etc. It's not very difficult, honestly.

  9. Hey Cliff - would have loved to know your favored spots, based on weather patterns, to watch the Perseids.

    Don't get me started on drivers - - I spend a fair amount of time in the car and phew, feel lucky to make it home after a sunny day OR the first rain!

  10. I'll admit it, I'm not the best driver out there. So I live close to work, walk lots of places, and take the bus if I'm going somewhere that's going to end up having challenging parking -- I HATE parallel parking. Or I make my husband drive.

    Everyone's got some superpower, and mine has nothing to do with cars.

    Anyone here have a Segway? I've been told that it's the ideal vehicle for my 3 miles but slightly uphill the whole way to the office commute (yes, that means it slightly downhill the whole way home, but who wants to get to the office all sweaty?) If it were the other way around, downhill to the office and uphill home, I'd be very inclined (groan) to ride my bike.

    I'm curious about how many days a year people who have Segways really use them. I think I'm hardcore enough to get some Gore-tex and use it most rainy days, but I don't know if I'd wuss out when it's also very cold. I know I'd be either driving or walking when it's snowy.

  11. 3 mile commute is quite doable on a bike of course. I believe the Professor does

  12. Hey Cliff,

    Why does so much of the heavy weather seem to skip past my North Tacoma home. I sit and watch other areas get lightning. My folks call from West Seattle and talk about the downpour. I watch the WU radar map. It all seems to slip by!


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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