What does the slippery when wet sign mean?

This sign is posted on a stretch of road and it has just started to rain. What does it mean for the way you drive?

Grip is lower here, so slow earlier and steer and brake gently

Some surfaces lose more grip than others when wet, and the first minutes of rain are the worst because oil lifts off the road. On low grip the mistake is rarely speed alone: it is sudden inputs, so brake earlier and turn the wheel less.

This sign is posted and rain has just started after a long dry spell. How should you drive?

Brake earlier and more gently, steer smoothly, and leave more space ahead

The first rain lifts oil and dust off the surface, and grip drops sharply before the road washes clean again. Everything you ask of the tires has to be gentler, and the space you leave in front is what gives you the time to be gentle.

You see this sign as light rain starts to fall. What changes about the way you drive?

Slow down and make your steering, braking and acceleration gradual

Grip on that stretch is lower than the road looks, and the first rain after a dry spell lifts oil to the surface, which makes it worse rather than better. Sudden inputs are what break traction, so smooth and early beats late and firm. Shaded corners and bridge decks stay slick the longest.

This sign is posted on a stretch of road and it has just started to rain after a long dry spell. What should you change?

Add distance to the vehicle ahead and make your steering and braking gentler

The first rain after a dry spell lifts oil and rubber off the surface, and this sign marks a stretch where grip is already lower than a driver would expect. More space in front buys you the extra distance you now need in order to stop. Smooth inputs matter because a skid starts with a sudden movement, not with speed on its own.

You pass this sign on a cold, damp day just before an overpass. Why does the surface on the overpass deserve extra care?

A bridge deck loses heat from below as well as above, so it can be icy while the road is not

A bridge has cold air under it as well as over it, so it chills faster than road built on the ground. That is why the first ice of the day often shows up on an overpass while the approach still looks merely wet.

Rain has started and you meet this sign on a busy two lane road. The car ahead of you holds its speed and stays in the middle of the lane.

Slow more than the car does and move out of the middle of the lane

A motorcycle puts two small patches of rubber on the road where a car puts four large ones, so the same wet surface costs you far more of your margin. The middle of a traffic lane is also where oil and rubber build up, and rain lifts that film to the surface. Slowing further and riding in a wheel track gives you cleaner pavement and more room to be wrong.