SEE notes for Truck Issues
Trucks and buses can visually block a rider from seeing or been seen by vehicles beyind the truck.
Trucks have huge blind spots, especially to the rear and on the right side, see Truckers 'share the road' campaign
Semi-trailer trucks also cut the corner in right turns. The right of a truck is a bad place to be.
Trucks can present other hazards, including debris projection from a burst tire, and wind from the truck's slipstream. Our secton on restricted access highway riding has more on trucks.
Slipstream and wind in general will force you to correct the line of the bike and can cause positioning problems, which is a problem if there are other bikes near. This is especially a problem when riding in a group.
Is there likely to be any threat you can't see beyond the truck?
If the truck is behind you, evaluate its braking distance to avoid a rear-end. Evaluate also the ability of the truck driver to see you.
If one side is blocked by a truck, consider moving beside the truck to use the visual block as a physical block, and concentrate on being conspicuous on the visible side.
Consider altering speed or changing lane to put some distance between you and the truck.
If following a truck, you are probably more visible to the truck driver in the left sub-lane, although in city streets this can be hard to do as trucks generally take up almost the entire width of the lane.
See also the notes in the restricted access highway page.
Truck braking distances are very long. A truck behind you can't stop as quickly as you can. If a truck is behind you, you need to keep a bigger space cushion to the rear.