Talk about your timely questions:

Q: I moved to Hillsboro from San Diego recently. For the first time ever, I hear people talking about how the first rain after a long, dry period is one of the most dangerous times to be driving road because oils rising out of road makes things extra slippery. Is this true or just an urban myth? Is there science to support?

A: Hopefully, your defensive-driving skills aren’t too rusty. After a record-setting three-month dry spell in the Portland area, the rains of autumn are predicted to start on Friday. And, scientifically speaking, the pavement will indeed be more slippery.

This topic was even covered by the Discovery Channel’s “Mythbusters.”

During long periods of dry weather, oils and other fluids from automobiles dry and build up on roads. The so-called “first wet” is indeed the most hazardous. That’s when rainwater loosens the surface oils, creating nasty, greasy driving surfaces that often catch drivers off guard.

I’ve even seen transportation and insurance studies showing that many people need a readjustment to driving in rain after the summer months.

After an especially long dry spell, the roads can feel like black ice when drivers hit the brakes. The dangers also exist for motorcyclists and bicyclists, especially with those same oils getting washed onto streetcar tracks.

When those rain drops start hitting the windshield on Friday, be cautious. Give yourself extra room to brake. And, for the love of Henry Ford, don’t tailgate.

Also, statistically speaking, ODOT is busy with more traffic-jamming highway crashes if the first hours of a rainstorm correspond with rush hour. So, with the wet set to hit in the afternoon, be ready for a longer drive home Friday.

One more thing: It might be a good time to check if you need new windshield wipers.

Update: ODOT has released its own tip sheet for commuting in the rain.

Q: Already on the far right biking up North Williams Avenue. Need I further yield to Legacy Emanuel Medical Center ambulances by stopping?

A: As a bicyclist, you probably want to be treated equally on the road. And in the eyes of Oregon law, you are indeed equal to a car, truck or TriMet bus on the road.

ORS 811.145 requires a "person" operating a "vehicle" (and a bicycle is defined as a vehicle by statute) to yield the right of way to an emergency vehicle with a visual or audible signal. That means you need to pull as near as possible to the right curb or edge of the road and stop -- and remain in that position until the emergency vehicle has passed.

The statute “also requires that pedestrians yield the right of way to emergency vehicles,” said Portland attorney Ray Thomas, who specializes in bicycling and pedestrian issues.

Even if the law gave bicyclists a pass, you should ask yourself: Are a few seconds of inconvenience for you really worth getting in the way of that ambulance and the person who needs its help?-- Joseph Rose