4.3 Rain, Fog, Hydroplaning & Winter Driving

Massachusetts weather ranges from summer downpours to nor'easters. The manual's rule is simple: weather that makes it harder to see, start, stop or turn requires lower speed and more space, whatever the posted limit says (Section 7.1).

Driving in Rain

• Rain and wet roads make it harder to start, stop and turn, and heavy rain, fog and mist make it harder to see.
• The law requires headlights whenever you use your wipers, and daytime running lights are not sufficient.
• Slow down as soon as the rain starts. Many roads are most slippery when rain first mixes with road dirt and oil, forming a greasy film.
• Wet leaves can be as slippery as ice.
• Leave more space, and be ready to stop within the distance you can see. A large truck may need twice as much distance to stop as a car or motorcycle, especially when roads are wet or icy.
• Keep wipers and window defoggers in good condition, and always signal.
• Avoid puddles, because wet brakes do not work right. If you drive through a deep puddle, apply the brakes lightly to dry them until they feel normal again.

Hydroplaning

Hydroplaning happens when your tires ride on a layer of water instead of the road. Road conditions, water depth and speed all play a part. The manual is blunt: if your vehicle starts to hydroplane, you're driving too fast.

How to respond:

1. Slowly take your foot off the gas pedal.
2. Never hit the brakes.
3. Never turn suddenly.
4. Let the car slow until the tires regain contact with the road.

Braking or jerking the wheel while hydroplaning can throw the car into a skid. Worn tires (below 2/32 inch, Section 3.1) and underinflated tires make hydroplaning more likely.

Driving in Fog

• Use low beams to reduce glare. High beams reflect off the fog back into your eyes.
• If you cannot see the pavement or sign posts, slow down and use the road edge markings to guide you.
• Always use turn signals so others can see your intentions.

The MassDOT Highway Division's 511 service gives 24/7 traffic, weather and construction information.

Winter Driving

Vehicles handle very differently on ice and snow, and the manual recommends practicing winter driving with your supervisor.

Clear the Whole Vehicle

Remove all ice and snow from your vehicle before driving. Clear every window, the wipers, headlights and brake lights. Clear the roof, hood and trunk too, so snow and ice do not blow onto vehicles behind you. If you do not, you can be charged with negligent operation.

Winter Readiness

• Keep the gas tank at least half full to prevent fuel-line freezing.
• Fill the washer reservoir with fluid that will not freeze.
• Carry a blanket, flashlight and small shovel, along with the winter kit from Section 3.1 (winter tires, ice scraper, jumper cables, warm clothing).
• Keep wipers and the defroster working.

Anyone who plows for pay must have commercial plates.

Weather Scenarios

1. First rain after a dry week: the road is at its slickest, so slow down immediately and add following distance.
2. The steering suddenly feels light on a flooded highway: you may be hydroplaning. Ease off the gas, keep the wheel straight, and do not brake.
3. Dry road, then a bridge on a 30 °F morning: expect ice on the bridge deck even though the road before it is clear.
4. Car covered in snow, late for school: clearing only a peephole is illegal and dangerous. Clear the roof, hood, trunk, lights and all windows.

Why New Drivers Should Practice in Bad Weather

The manual encourages practicing winter driving, and the permit period is the time to do it with an experienced supervisor beside you. Choose an empty, legal parking area for a first feel of how the car brakes and steers on snow, then work up to quiet roads. Learning how your car behaves in rain, fog and snow before you drive alone is one of the best uses of your 40 supervised hours.

Connecting to the Speed Law

The Massachusetts fundamental speed law requires a speed that is reasonable for traffic, road and weather conditions. The manual's example: driving 40 mph in a heavy rainstorm on a highway with a 50 mph limit can still get you a ticket for driving too fast (Section 7.1).