Two-wheel drive trucks and rear wheel drive cars don’t move well in the snow. An empty bed or trunk doesn’t provide enough weight on the back axle for the drive wheels to grip the ground.
Cement blocks are an excellent choice to put in the bed of your truck or in your trunk to add weight to improve traction so you can get around. Be sure to place them right on top of the rear axle. Putting them behind the axle could make handling worse because it would lift the front end and reduce front wheel traction. Make sure the blocks are secure in the bed/trunk so that they don’t go flying in the event of a short shop. You can do this by threading a rope through the holes in the blocks and then tying the ends to the truck bed. Be sure to test drive it first to make sure they’re secure. Keep adding and removing blocks until you’re happy with how the vehicle handles.
Cement blocks are also a green choice because you can recycle them in the spring into a project around the yard. You could build a raised garden bed, a retaining wall, steps or a patio.