Drivers are expected to show reasonable care when they transport bulky items. Furniture carried in the bed of a pickup truck, items strapped to a vehicle roof, and anything protruding from the trunk needs to be properly secured.

Most drivers make only infrequent trips with this kind of cargo, but they become more common in December. Families who purchase a natural Christmas tree will usually tie it to the roof of their vehicle to bring it home.

Losing an item from your vehicle is more than just an inconvenience. It will also leave an unexpected hazard in the road, posing a risk to other drivers.

In a 2004 study, the AAA Foundation for Traffic Safety concluded that an estimated 25,000 crashes in North America occur each year due to debris on the road. These accidents usually result in property damage only, though the organization estimates that they account for 80 to 90 deaths a year as well.

There are several ways road debris can cause an accident. A driver might collide with an object and damage their vehicle, or they might hit another vehicle or barrier while swerving to avoid the debris. Drivers may also collide with vehicles that unexpectedly stop for the debris or with a person who is trying to remove items from the road.

Most road debris crashes are caused by wheels, tires, or tire treads on the road. However, accidents can also be caused by furniture, construction materials, tools, and other items that fall from a vehicle.

When transporting cargo, it is important to make sure it won't slide around or become loose during the trip. Connecticut law says vehicles should not be driven on any highway unless their cargo is loaded in a way to prevent it from "dropping, sifting, leaking or otherwise escaping" from the vehicle and causing a "hazard or nuisance to other users of the highway." Drivers who violate this law can be fined.

Check the weight limit of your vehicle to see how much cargo you can safely carry. Popular Mechanics says this figure is usually included on a sticker inside the driver's side door. Don't forget that this total is for the combined weight of passengers and cargo.

The roof rack will have a weight limit as well, and exceeding it increases the chance that the cargo will become dislodged from the vehicle. You should also stay within the weight limit of any trailers and make sure your vehicle is capable of towing the load.

When securing loads in a pickup truck bed, use material that will be strong enough to withstand unexpected swerves and bumps. The magazine Family Handyman says rope, bungee cords, and twine are not enough for large loads. Heavy-duty ratchet straps will keep cargo tightly restrained.

Bundle together loose items, such as lumber, and anchor them to the available support rings in the pickup bed. Cargo nets can also be fastened over a load to keep items from bouncing out.

Bulky cargo should be secured from four ends, with the straps forming an "X" over the center of the load. This arrangement can shift over time, so you should check the straps at least once every 100 miles and adjust them as necessary.

Mattresses are a particularly tricky item, since they can be blown up by the wind and break any flimsy restraints. It is also difficult to transport a mattress on the roof of a vehicle, since straps that are run through the windows will make it impossible to open the doors. For these reasons, Popular Mechanics recommends against transporting a mattress on the roof of a passenger vehicle.

You may be able to retrieve any dropped cargo if you are on a less traveled route and able to safely venture into the road to pick up items. However, it is extremely dangerous to try to retrieve items from a multilane highway with vehicles passing at high speeds. Aaron Crowe, writing for Insure.com, says drivers who lose cargo on these roads should take the next exit and immediately report the situation to police.

If another driver collides with an item that falls from your vehicle, they can hold you responsible for the damage. The Wise Insurance Group of Dallas, Texas, says you are liable for these costs if your vehicle is identified as the source of the road debris. Drivers who suffer damages from this debris will then be able to make a claim on your car insurance.